Mastering GTO Restorations: Bodywork Guide

Good bodywork is the founda­tion of a quality paint job. You can’t have one without the other. How many times have you looked at a shiny, new paint job at a distance only to inspect it up close and find a visual nightmare of poor panel align­ment, waves, and sanding scratches? This is the result of a lack of prepa­ration for the paint. The finer points of painting and body alignment are covered in Chapter 4; this chap­ter lays down that foundation with proper bodywork.

 


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Looks can be deceiving. This 1970 Judge convertible seemed to have a solid body not requiring extensive body work. However, it was hiding some sig¬nificant problems. In addition to both rear quarters needing to be replaced, it needed new floorpan panels, as well as new portions of the trunk floor. The interior was removed to reveal that the floorpans were rusted in certain areas and needed to be replaced. Inspecting the trunk also revealed a certain amount of rot that necessitated patches. While both quarter panels seemed to be solid from the outside, a lot of rust was lurking around the wheel wells and these needed to be replaced. (Photo Courtesy Scott Tiemann)

Looks can be deceiving. This 1970 Judge convertible seemed to have a solid body not requiring extensive body work. However, it was hiding some sig¬nificant problems. In addition to both rear quarters needing to be replaced, it needed new floorpan panels, as well as new portions of the trunk floor. The interior was removed to reveal that the floorpans were rusted in certain areas and needed to be replaced. Inspecting the trunk also revealed a certain amount of rot that necessitated patches. While both quarter panels seemed to be solid from the outside, a lot of rust was lurking around the wheel wells and these needed to be replaced. (Photo Courtesy Scott Tiemann)

Typical Rust Areas

From 1964 to 1972, Pontiac GTOs were built on the same GM A-Body that was shared with the Chevelle, Skylark, Cutlass, and of course, the Pontiac Tempest and LeMans. As you expect from cars sharing the same basic platform, they all suffered from the same problem areas where water and road salt collect and corrode sheet metal.

The windshield and backlight areas are prone to window gasket fail­ure, which lets water collect in those areas. As the corrosion progresses, the moisture moves downward and the corrosion follows. In the front, the windshield base is compromised, as are the cowl and firewall areas. Out back, water can collect in the trunk floor, the seams of the trunk wells, the rear quarters, and wheel wells. At the same time, road salt and water are working on the mating seams of the rear quarters and outer wheel wells, as well as the rocker panels.

Fortunately, all unrestored GTOs don’t end up as rusted-out parts cars. While it is tough to find a solid GTO in the Northeast or Midwest, the elements are far kinder to Southern and Southwestern examples. Regard­less of what corrosion damage you might find, if the overall structural integrity of the car is still sound, often the car is a good candidate for restoration.

Paint Removal

A proper foundation for paint means removing old paint. Many body shops scuff up and paint over an existing finish to save time and money. While this might be fine for repairing a fender-bender or freshen­ing the look of a used car for resale, it is necessary to remove the paint down to the metal so you have the best paint adhesion and of course the best results. Not doing so is putting way too much faith in old materials and labor you really aren’t familiar with. Taking the time to do it right will give the results that you want  no one wants to see a substandard finished product every time you open the garage.

There are several methods for paint removal and if done correctly, each does a very good job. Each has certain benefits and drawbacks. When each method is done incor­rectly, the results can be disastrous.

Sanding

It’s tedious, time-consuming, and messy, but it is the time-honored method of paint and rust removal. There is a balance here that has to be maintained the balance between saving time and being too aggressive with the paper grit. If you are using a right-angle grinder/sander, be very careful, as it can generate enough heat to warp sheet metal. It also removes more metal than necessary and leaves very deep scratches, which can add time to repair. A dual-action (DA) orbital sander is not as aggressive it is easier on the metal but takes longer to accomplish the same job.

My suggestion is to start with a less-aggressive grit and use a DA orbital sander. As you become more familiar with how they perform, you can get more aggressive with the paper grit, maybe even switch over to a right-angle grinder and work from there.

Chemical Stripping

Chemical stripping falls into two categories of applicationindustrial and brush-on. In the industrial appli­cation, the entire body is dipped in huge vats filled with an acid or alka­line solution that takes off all paint and rust, leaving only the bare metal. Brushing on a chemical stripper soft­ens paint and filler, making it easy to scrape off, revealing clean, bare metal. I have worked with both and no matter how you do it…it ends up a gooey mess.

The brush-on application is a practical way for the at-home restorer to strip the paint from the body. In addition, it is a good way to get paint and filler off large panels, such as roofs, hoods, decklids, and doors.

I have had good luck using strip­per on the main area of a hood, while leaving the edges for a sander later. That way, I took advantage of the time-saving chemical strippers offered while still preventing damage to new paint in the future.

Whatever brand of stripper you use, make sure you have plenty of ventilation as the fumes can be strong. Gloves are mandatory as well, as chemical strippers can cause severe drying of the skin and/or chemical burns.

Chemical strippers work well but are messy and disposal can sometimes be a prob¬lem. They are applied with a brush, and due to their viscosity, they stick to vertical surfaces without dripping off. The stripper doesn’t need a thick coat to be effective, but it does need some time for the paint to start bubbling and lifting. The directions say to let it sit for 30 minutes to three hours but I suggest letting it sit for at least three hours. After the paint is lifted, scraping with a putty knife is necessary. You may have to apply a second coat or wire brush off the primer coat to get it off. (Photo Courtesy Eastwood Products)

Chemical strippers work well but are messy and disposal can sometimes be a prob¬lem. They are applied with a brush, and due to their viscosity, they stick to vertical surfaces without dripping off. The stripper doesn’t need a thick coat to be effective, but it does need some time for the paint to start bubbling and lifting. The directions say to let it sit for 30 minutes to three hours but I suggest letting it sit for at least three hours. After the paint is lifted, scraping with a putty knife is necessary. You may have to apply a second coat or wire brush off the primer coat to get it off. (Photo Courtesy Eastwood Products)

If you have the option to take the body shell and panels to a com­mercial company to do the stripping for you, it is a big time-saver, albeit a fairly expensive one.

Acid Dipping: Acid dipping is also known as chemical milling. In addi­tion to removing all paint, primer, and filler, it also removes a certain amount of the metal, depending on the amount of time the part is immersed. Race car builders have used the process for decades to remove weight from a car body while still maintaining the original mate­rial and appearance. The downside to acid dipping is that it is corrosive to metal. It also tends to work-harden it. There is also the possibility that if not properly rinsed, acid can remain in seams and other areas, destroying paint and causing further corrosion.

Alkaline Dipping: Alkaline dip­ping uses liquid on the other end of the pH scale from acid. The advan­tage is that while it is very effective at getting rid of rust and bondo, it leaves the “good,” or non-corroded, metal alone. This process is costly and the alkaline must be removed from the seams to prevent potential paint damage. Given the choice of the two, the alkaline process is better for restorations. The RediStrip pro­cess is offered at franchises around the United States and is especially good for restoration work.

As with acid dipping, be careful about getting the stripper in body seams and other places where it can be trapped and cause paint damage later.

Media Blasting

For many years, sandblasting was the only available form of media blasting. While it is very effective at removing rust, paint, and old filler, it is a process that can easily destroy sheet metal, both from the abrasive action and from the frictional heat it develops. Plus, if you aren’t careful, you could blast a hole right through a fender. Sandblasting sheet metal requires an even technique and inex­perienced restorers destroyed many parts learning this lesson.

Today, new processes are just as effective without the detrimental effects of sand, most notably soda blasting. While soda blasting might sound like spraying a Coke or Pepsi firehose at the body, it actually refers to baking soda (sodium bicarbonate). If you look at it under a microscope, you see that it is not really a powder but is actually crystalline. When the media is accelerated to high speed, millions of tiny explosions occur and the paint is stripped away.

Media blasters come in many different types and sizes. Sandblasters have been around for quite a long time and effectively strip the paint and rust off the body panels of your A-Body car. For the home restorer, soda blasters, which use baking soda as the medium, are a great choice, as they are fairly inexpensive, safe to glass and trim, strip paint very quickly, and are environmentally friendly. They also leave a rust-inhibiting coating, which needs to be removed before priming and painting. The blaster works just like a sandblaster, using an air compressor, a hopper for the baking soda, and a hose and nozzle. Work the area carefully to avoid stripping any area you want to preserve, and be sure to wear proper clothing, eye protec¬tion and a respirator. (Photo Courtesy Eastwood Products)

Media blasters come in many different types and sizes. Sandblasters have been around for quite a long time and effectively strip the paint and rust off the body panels of your A-Body car. For the home restorer, soda blasters, which use baking soda as the medium, are a great choice, as they are fairly inexpensive, safe to glass and trim, strip paint very quickly, and are environmentally friendly. They also leave a rust-inhibiting coating, which needs to be removed before priming and painting. The blaster works just like a sandblaster, using an air compressor, a hopper for the baking soda, and a hose and nozzle. Work the area carefully to avoid stripping any area you want to preserve, and be sure to wear proper clothing, eye protec¬tion and a respirator. (Photo Courtesy Eastwood Products)

 

This 1964 GTO body was stripped using the soda blaster and the end result is a thing of beauty. All of the paint was removed, leaving a beau¬tiful foundation for a show-winning paint job. (Photo Courtesy Scott Tiemann)

This 1964 GTO body was stripped using the soda blaster and the end result is a thing of beauty. All of the paint was removed, leaving a beau¬tiful foundation for a show-winning paint job. (Photo Courtesy Scott Tiemann)

Baking soda is fine enough as a very gentle paint remover. In fact, it is so gentle that you can remove one paint layer at a time. Best of all, you can save time by not having to mask everything off, as the soda does not hurt chrome, rubber, or glass. Obvi­ously, this is not the most effective means of rust removal, but it takes off light to moderate surface rust on sheet metal. In addition, unlike sandblasting, you won’t risk warp­ing or blowing a hole in the sheet metal. For paint removal, it’s a very good choice. The media leaves a rust-inhibiting coat on the bare metal, which needs to be cleaned off before priming or painting.

Equipment can be rented or pur­chased, and certain companies will do the job for you. Eastwood and Harbor Freight, among others, have a wide variety of reasonably priced kits and soda media for home use. East­wood also sells a combination of bak­ing soda and aluminum oxide, which is formulated to work with its blaster and more effectively remove rust, though it does harm trim and glass.

Of course, there are other types of abrasive media such as plastic, pulverized walnut shells, even dry ice. For the home restorer, the soda blaster represents the best over­all media-blasting system avail­able, from the standpoints of cost, ease of use, safety to delicate trim, and ease of disposal. Baking soda is eco-friendly and you are not try­ing to get rid of non-biodegradable refuse, as with the acrylic medias used in plastic media blasting. The equipment is not terribly expensive, it is ridiculously simple, and for all intents and purposes, it’s idiot-proof. Where you can quickly and easily cause sandblast damage, the soda blaster is much more forgiving without having to sacrifice results. When you add that up and see how quickly it does the job, combined with the ease of disposal, the choice really is a no-brainer.

Repair Patches

Metal patches made to original body panels go a long way to sav­ing money and retaining a measure of originality. The 1964 GTO shown here was the original Car and Driver magazine test car that appeared in the now-legendary “GTO vs. GTO” article in the March 1964 issue. As such, this particular GTO has an immense amount of history behind it, and it was deemed important by both the owner, Tenney Fairchild, and the restorer, Scott Tiemann of Supercar Specialties, to integrate as much of the original sheet metal as possible into the restoration.

Fortunately, this GTO was in remarkably good condition for a rust-belt car, having spent nearly 20 years in storage. While it displayed corrosion in most of the typical spots seen in cars of this age, it had not advanced very far, so it was feasible to repair much of the damage with simple, hand-fabricated patch panels cut from sheet metal.

Once the paint and rust are removed from this 1964 GTO fender by way of a soda blaster, the repair can begin. (Photo Courtesy Scott Tiemann)

Once the paint and rust are removed from this 1964 GTO fender by way of a soda blaster, the repair can begin. (Photo Courtesy Scott Tiemann)

 

This close-up shows that the rust-through damage is fairly localized and doesn’t extend to the edges. This fender is a good candidate for a repair patch. (Photo Courtesy Scott Tiemann)

This close-up shows that the rust-through damage is fairly localized and doesn’t extend to the edges. This fender is a good candidate for a repair patch. (Photo Courtesy Scott Tiemann)

The process was fairly simple. One fender was stripped down to the bare metal inside and out. Scott carefully cut out the rusted section using a reciprocating saw, and then cut a patch out of 18-gauge sheet metal, closely matching the shape of the hole. He then tacked-welded it in place, placing the welds about 1 inch apart.

After inspecting the repair for fit, the patch was completely welded in. The welds were then ground flush with the original sheet metal and the front side of the repair was completed.

There was also some rust dam­age to the fender support brace just behind the original rust damage. That area was also treated to the same prep­aration, a patch was cut, welded in, and the welds ground flush. This pro­cess returned the fender to its original appearance and structural integrity without replacing the factory-installed panel. A small amount of filler may be needed to completely smooth the area prior to painting, but at this point, the repair is complete.

Floorpan and Trunk Floor Replacement

Floor and trunk pans are areas that are frequently rusted out from continued exposure to moisture and salt. Depending on where your car is from, the damage could be as minor as pinholes in a foot well to entire sections no longer being present. Fortunately, the solutions are as large or small as the damaged areas.

Before reproduction floorpans became available, repair methods ran the gamut from using NOS sheet metal obtained from dealers to cut­ting floors out of rust-free Western cars to welding in fabricated patch panels. Other more creative meth­ods, such as using expanded sheet metal covered with fiberglass cloth has been used, as was riveting on a piece of sheet metal or even just lay­ing a piece of sheet metal over the hole and letting the carpeting hold it in place.

For some reason, where I come from in Upstate New York, it was all the rage in the 1970s and 1980s to steal stop signs and cut them up to make floorboards. I’m not sure what the reasoning was, as the metal used was much thicker than production car floorboards and was not even steel they’re silk-screened alumi­num. I suppose it was more the thrill of obtaining the stop sign than its suitability as a replacement panel.

In any event, the aftermarket came to the rescue, saving these would-be scofflaws from months of possible jail time and commu­nity service, as well as helping law-abiding restorers regain the structural integrity they lost to the elements.

Replacement floorpans and trunk floors are engineered to fit right and restore integrity to the body. Like the originals that they replace, the repro­duction floor panels are stamped from the correct-gauge sheet metal and feature the same ribs and con­tours as the originals to make their installation as trouble-free as pos­sible. Companies that manufacture and sell these panels include Year One, Ames Performance Engineer­ing, Original Parts Group, Perfor­mance Years, National Parts Depot, and Dynacorn.

Further aiding the restorer are the sizes of replacement pans avail­able. In some cases, the rust damage is limited to one area, such as below the accelerator, brake, and clutch pedals.

MIG-welding body panels whether it’s fenders, quarter panels, or floor¬pans is an art. If you have not used a welder before, it’s wise to take a class and develop the necessary skills. If you’re a quick learner you can practice in your garage. Body panels are typically 14- or 16-gauge sheet-metal steel, and if your MIG welder is set too high or you apply too much heat to a particular area, you can easily burn through the sheet metal and ruin the component.  Therefore, set the welder at a lower voltage for welding thin metals. I rec¬ommend at least practicing the tack and stitch welding required for the floor installation on some scrap metal before attempting to install the floorpans. The patch panel and the existing sheet metal should overlap slightly and the gap should be minimal so fill welding is not required later. Apply the weld every 4 to 5 inches, quench the area with water or air, and then apply the next tack weld. If you don’t allow the welded area to properly cool before applying the next tack weld in the same area, the panel warps. If it warps, corrective measures must be taken using a hammer and dolly to straighten the body panel, which is time consuming and frustrating. Tack weld the patch into place and inspect the repair for fit. When it is deemed satisfactory, completely weld in the panel, making sure that the heat is not so hot that it warps the metal. Then grind the weld flush and prime it. (Photo Courtesy Scott Tiemann)

MIG-welding body panels whether it’s fenders, quarter panels, or floor¬pans is an art. If you have not used a welder before, it’s wise to take a class and develop the necessary skills. If you’re a quick learner you can practice in your garage. Body panels are typically 14- or 16-gauge sheet-metal steel, and if your MIG welder is set too high or you apply too much heat to a particular area, you can easily burn through the sheet metal and ruin the component.
Therefore, set the welder at a lower voltage for welding thin metals. I rec¬ommend at least practicing the tack and stitch welding required for the floor installation on some scrap metal before attempting to install the floorpans. The patch panel and the existing sheet metal should overlap slightly and the gap should be minimal so fill welding is not required later. Apply the weld every 4 to 5 inches, quench the area with water or air, and then apply the next tack weld. If you don’t allow the welded area to properly cool before applying the next tack weld in the same area, the panel warps. If it warps, corrective measures must be taken using a hammer and dolly to straighten the body panel, which is time consuming and frustrating. Tack weld the patch into place and inspect the repair for fit. When it is deemed satisfactory, completely weld in the panel, making sure that the heat is not so hot that it warps the metal. Then grind the weld flush and prime it. (Photo Courtesy Scott Tiemann)

 

If the support brace just behind the outer sheet metal is also rust dam¬aged, cut and weld in a patch as on the outer-section repair. Grind the repair smooth so the fender regains its original appearance and integrity. (Photo Courtesy Scott Tiemann)

If the support brace just behind the outer sheet metal is also rust dam¬aged, cut and weld in a patch as on the outer-section repair. Grind the repair smooth so the fender regains its original appearance and integrity. (Photo Courtesy Scott Tiemann)

 

Once the floorpans are rusted and weakened, they need to be replaced. Several tools can be used to cut out the rusted-out floors of a GTO. Most use a plasma cutter. If you use a plasma cutter, use it with care and precision. You can inadvertently cut through the frame rail, floor support, and other components much faster than you’d think. So be deliberate and careful because you don’t want to patch and repair those from inadvertently cutting them with a torch. To remove the floors, use a rotary cutoff tool, which takes some time and is hard work. Use a 3-inch disc in 1/32- or 1/16-inch thickness, and do yourself a favor by buying a high-quality disc, such as one from 3M. Use the cutoff wheel to precisely cut out the rusted and weakened factory floorpans. Use the replacement pans as templates for cutting. Take precautions to ensure the original floor bracing is not harmed in the process. Though these look bad, they are actually in great shape. Most of the rust seen on them is from pieces falling from the floor panels, not from the braces. (Photo Courtesy Scott Tiemann)

Once the floorpans are rusted and weakened, they need to be replaced. Several tools can be used to cut out the rusted-out floors of a GTO. Most use a plasma cutter. If you use a plasma cutter, use it with care and precision. You can inadvertently cut through the frame rail, floor support, and other components much faster than you’d think. So be deliberate and careful because you don’t want to patch and repair those from inadvertently cutting them with a torch. To remove the floors, use a rotary cutoff tool, which takes some time and is hard work. Use a 3-inch disc in 1/32- or 1/16-inch thickness, and do yourself a favor by buying a high-quality disc, such as one from 3M. Use the cutoff wheel to precisely cut out the rusted and weakened factory floorpans. Use the replacement pans as templates for cutting. Take precautions to ensure the original floor bracing is not harmed in the process. Though these look bad, they are actually in great shape. Most of the rust seen on them is from pieces falling from the floor panels, not from the braces. (Photo Courtesy Scott Tiemann)

 

The floorpans are a major structural component of the body, and therefore when cut¬ting out the floors, the body can move out of alignment. You don’t want to install the floorpans when the body isn’t square. Hence, you need to install these brace bars and take the proper measurements to ensure that the body is square. This is not really necessary for a floorpan replacement, but if your car is also getting quarter panels it needs the support. These floor braces have been soda blasted and primed. Once the floor braces are stripped, the pans are ready for installation. (Photo Courtesy Scott Tiemann)

The floorpans are a major structural component of the body, and therefore when cut¬ting out the floors, the body can move out of alignment. You don’t want to install the floorpans when the body isn’t square. Hence, you need to install these brace bars and take the proper measurements to ensure that the body is square. This is not really necessary for a floorpan replacement, but if your car is also getting quarter panels it needs the support. These floor braces have been soda blasted and primed. Once the floor braces are stripped, the pans are ready for installation. (Photo Courtesy Scott Tiemann)

 

While some purists may use a clean floor from a donor car, you can install a reproduction floor on your GTO. Mark the alignment for the new floor¬pans, then measure and cut for a butt weld to the existing sheet metal. To maintain accu¬rate alignment throughout this tack welding stage, drill holes around the perimeter of the replacement sheet-metal floor to hold it in place. This is done to locate them and keep them in the proper position during the welding process. Also drill holes in the areas just above the floorpan supports, so they can be easily welded to it. Then, using a MIG welder, place tack welds every 3 or 4 inches along the floor braces. Be careful when applying these welds because you don’t want to burn through the thin sheet metal or apply too much heat, causing the floors to warp. (Photo Courtesy Scott Tiemann)

While some purists may use a clean floor from a donor car, you can install a reproduction floor on your GTO. Mark the alignment for the new floor¬pans, then measure and cut for a butt weld to the existing sheet metal. To maintain accu¬rate alignment throughout this tack welding stage, drill holes around the perimeter of the replacement sheet-metal floor to hold it in place. This is done to locate them and keep them in the proper position during the welding process. Also drill holes in the areas just above the floorpan supports, so they can be easily welded to it. Then, using a MIG welder, place tack welds every 3 or 4 inches along the floor braces. Be careful when applying these welds because you don’t want to burn through the thin sheet metal or apply too much heat, causing the floors to warp. (Photo Courtesy Scott Tiemann)

 

Professionally installed floorpans look similar to this when viewed from under¬neath the car. The seams, panel stamping, and alignment with the floor braces make it appear as the original one-piece unit. Grind down the tack welds and prime and paint the floor. Once the area is properly finished, the repair is nearly invisible and restores the integrity of the body. A floor replacement, such as this, adds value to the restored car. On the other hand, if the stamping and panel alignment is off, a potential buyer or show judge will recognize this issue and the car will be worth less and points deducted. Replacing floors for the first time takes care, attention to detail, and diligence. (Photo Courtesy Scott Tiemann)

Professionally installed floorpans look similar to this when viewed from under¬neath the car. The seams, panel stamping, and alignment with the floor braces make it appear as the original one-piece unit. Grind down the tack welds and prime and paint the floor. Once the area is properly finished, the repair is nearly invisible and restores the integrity of the body. A floor replacement, such as this, adds value to the restored car. On the other hand, if the stamping and panel alignment is off, a potential buyer or show judge will recognize this issue and the car will be worth less and points deducted. Replacing floors for the first time takes care, attention to detail, and diligence. (Photo Courtesy Scott Tiemann)

 

A thorough inspection of this 1970 GTO Judge convertible revealed major rust damage in several areas. In particular, the quarter panels suffered major rust damage, and these parts required replacement in some cases and major repair in other cases. Water spray from passing cars often leads to more rust on the driver’s side of the car, and in this case, the driver’s side is far worse than the passenger’s side.  Although the driver’s side was worse than the pas¬senger’s side, the passenger-side quarter panel still needs to be replaced. Use an air-powered rotary cut off tool to cut out the rusted outer skin below the beltline. Use the replacement panel to guide the cut off tool across the rusted skin and achieve a straight cut. Drill out the factory quarter-panel spot welds, so the panel can be removed. Use a special spot weld drill bit, which drills a 1/8-inch hole in the center and then cuts away the top metal in the spot weld until it is freed from the bottom half of the weld. Note that this rocker panel is still in very good condition and the outer wheel well only has minor rust-through along the edges. (Photo Courtesy Scott Tiemann)

A thorough inspection of this 1970 GTO Judge convertible revealed major rust damage in several areas. In particular, the quarter panels suffered major rust damage, and these parts required replacement in some cases and major repair in other cases. Water spray from passing cars often leads to more rust on the driver’s side of the car, and in this case, the driver’s side is far worse than the passenger’s side.
Although the driver’s side was worse than the pas¬senger’s side, the passenger-side quarter panel still needs to be replaced. Use an air-powered rotary cut off tool to cut out the rusted outer skin below the beltline. Use the replacement panel to guide the cut off tool across the rusted skin and achieve a straight cut. Drill out the factory quarter-panel spot welds, so the panel can be removed. Use a special spot weld drill bit, which drills a 1/8-inch hole in the center and then cuts away the top metal in the spot weld until it is freed from the bottom half of the weld. Note that this rocker panel is still in very good condition and the outer wheel well only has minor rust-through along the edges. (Photo Courtesy Scott Tiemann)

The factory carpeting has a vinyl mat area that can trap moisture from wet footwear, leaving the area prone to rust-through. For jobs such as this, quarter sections are available for front and rear on both sides.

Replacement floorpans also come in left and right halves, front to rear, as well as full-floorpan stampings.

These replace the entire floor from the rockers to the firewall to the wheel wells and trunk. They can even include support braces and rocker panels, if you wish essentially the entire bottom of the body. This is an attractive alternative in cases where the rust is severe, though some restorers prefer to weld the smaller pieces together, as they are easier to handle than one large piece and save money on shipping costs.

Keep the condition of the pas­senger compartment floor and the trunk floor in mind when evaluat­ing the car. Make sure that you are poking and prodding the entire area with a rubber mallet and a screw­driver. In addition to rust holes, look for weakening of those areas with heavy surface rust.

If you find that you can get the floorpans to deflect even a little with your hands, it is a clear indicator that their strength has been com­promised by corrosion. They should be replaced, even if there aren’t any visible holes because the structural integrity of the body is compro­mised, and ultimately it’s a safety issue. You don’t want to have seats falling through the floors six months after the car is finished. Take the time to carefully evaluate what you have while the car is all apart, because it will never be easier to weld in new floorpans than it is at this stage.

The procedure for welding in new floorpans involves careful mea­suring and cutting away of the origi­nal floor. The idea is to remove only as much metal as necessary to prop­erly install the panel to solid, original metal. Be careful to avoid cutting the support braces; they may be reus­able. If you are finding that you are cutting into more and more rusted metal, keep cutting until you find solid metal, even if it means having to purchase additional panels. What good is it to weld in fresh reproduc­tion sheet metal to thin, corroded, compromised sheet metal? Again, safety and structural integrity is what you are going for.

Once the corroded metal has been removed, the area should be prepared with a grinder or recip­rocating saw to smooth the edges. As with the patch panel described earlier, the new pan should be tack welded every 1 inch or so and checked for warpage and fit. Once that is achieved and the job is sat­isfactory, finish welding in the pans and then grind down the welds for a correct appearance.

Quarter Panel Replacement

On areas where there is enough corrosion to negate the use of simple patches and warrant the replace­ment of entire exterior quarter pan­els, reproduction units should be obtained, as well as the support pieces behind them. This operation is quite involved and requires a great deal of preparation and planning.

Once you have made the deci­sion that replacement is necessary, it is time to order parts. It is advisable to wait until they arrive before cut­ting anything, as it is too easy to cut more away than is necessary, which complicates the process and slows things down. This is especially signif­icant when using lower-half quarters instead of the full units that extend into the C-pillar.

Once you have the new panels, carefully clamp them to the car so you can scribe lines to determine where to cut. If you are going for a full quarter replacement, use the fac­tory seams as a guide for cutting. If you are performing a full quarter replacement on a coupe or hardtop body style, the seam that mates to the roof panel has lead as a filler. Use a propane torch to remove the lead, but make sure that you are not heat­ing the roof panel enough to warp it. Just use as much heat as needed to remove the lead.

The inner wheelhouse on the passen¬ger side had some rust-through dam¬age, so a repair was necessary before the new lower quarter was installed. (Photo Courtesy Scott Tiemann)

The inner wheelhouse on the passen¬ger side had some rust-through dam¬age, so a repair was necessary before the new lower quarter was installed. (Photo Courtesy Scott Tiemann)

Be sure to wear a mask when per­forming this task and use caution. Lead is a poisonous substance, and you don’t want to risk your health. Be careful and use plastic filler when finishing the area.

 

Quarter Panel Replacement

Step-1: Cut Out Rust

1Use a small rotary cutoff tool to cut out the rusted portion of the inner wheelhouse. Carefully cut above the frame rail and between the trunk support rail as well as 4 to 5 inches of the rust-affected area. Cut out the rusted metal, leaving a void for the patch to cover. Cut a patch by hand with shears to replicate the edge of the cut as well as the lower edge of the wheelhouse (Photo Courtesy Scott Tiemann)

Step-2: Tack Weld to Wheelhouse

2Tack weld a 4- to 5-inch-wide by 24-inch-long piece of .040-inch-thick sheet metal to the solid metal wheelhouse. Measure the thickness of the original metal and use the same thickness in all repairs. Once the tack welds are placed, use a rotary grinding tool to smooth down the tack-weld heads. Place a bead along the entire seam and then smooth it down. Make and install a patch that loops around and meets the replacement outer wheelhouse. (Photo Courtesy Scott Tiemann)

Step-3: Weld Seam

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Shown here is a full replacement quarter panel for the pas­senger’s side. Although the replacement panel includes a full rear quarter, only the lower half is used for this particu­lar repair. In addition, there is a dent above the beltline on the panel, but with some coaxing and body filler the dent will be repaired. (Photo Courtesy Scott Tiemann)

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Use a MIG welder to place a bead of weld down the entire seam. When performing this work, ensure that the welder is correctly set, so you do not burn through the small patch you’re installing. The corner of the patch meets the inner wheelhouse, and the quality of this work is exceptional. You should strive to achieve the quality of work pictured here. As well as the quality of the welds, care must be taken with the grinding down of the welds. It is important to grind the weld and not any of the surround­ing metal, as it needlessly weakens the metal and causes an uneven contour. (Photo Courtesy Scott Tiemann)

Step-4: Smooth Out Seam

4The wheel-well housing repair has been completed and so has the area of the trunk adjacent to the wheel well. The rust in that area also necessitated that a corresponding patch in the trunk floor be installed. Once the tack welds and then the full seam welds are placed, use a rotary tool to smooth out the seam so it looks factory new. Remember to work on the welds and not the metal itself. (Photo Courtesy Scott Tiemann)

 

4aThis assortment of body parts also includes replacement inner wheel-well panels. In this particular case, the pieces came from Ames Performance Engineering. (Photo Cour­tesy Scott Tiemann)

 

 

Step-5: Weld on Wheelhouse

5Use a MIG welder to weld the reproduction outer wheelhouse onto the inner section and to the inner section of the trunk sump area. Smooth the welds with a rotary tool to achieve a clean look. (Photo Courtesy Scott Tiemann)

 

 

 

Step-6: Align Panel

6To install the panel, it must align with the adjoining body panels and be anchored in position. While the doors and fenders can be moved around once installed, the quarter panel is not removable and therefore it’s imperative to get the alignment correct. At this stage, look at all the adjoining body panels and ensure that they are correctly lined up. Look at the quarter panel and door gap; the same goes for the quarter panel and trunk lid gap. All these components need to be in alignment.

Drill through the adjacent sheet metal and bolt the panel into position. As with the rest of the panels used for this restoration, the quarter panel must be tempo­rarily fastened and located with bolts, allowing for shift-free positioning while it is tack and finish welded. Butt weld the lower quarter-panel section to the top half. Place body panel clamps and locking pliers on the bottom of the quarter panel and the inner wheel-well housing. From inside the trunk, weld the quarter panel to the trunk floor panel and the wheel well. (Photo Courtesy Scott Tiemann)

Step-7: Weld Quarter Panels Together

7Weld the upper quarter panel to the lower quarter panel using a butt-weld joint. Use a MIG welder to place a thin stitch weld along the entire seam of the quarter panel. This is extremely delicate work that requires correct welder settings and attention to detail. If the welding is too hot, you run the risk of warping the panel and ruining all your hard work. Once the stitch welds have been completed, use a rotary tool with a 36-grit, 5-inch, flexible 3M wheel disc to grind the beads smooth on the quarter in preparation for final finishing. As mentioned before, carefully grind down the weld and not the sur­rounding sheet metal. (Photo Courtesy Scott Tiemann)

Step-8: Align Panel with Bumper

8With the bumper installed, properly align the upper and lower quarter panel with the bumper. This level of body fit and alignment is needed for a concours-level restoration and will be rewarded with gold awards. (Photo Courtesy Scott Tiemann)

 

 

 

Step-9: Remove Paint

9Strip the entire body of paint in preparation for dent repair, paint, and alignment. Soda blasters are great for home restorers due to the low cost and the fact that the media is gentler than sand beads. However, you can use a two-step process, which begins with plastic media blasting and ends with a careful sandblasting of whatever rust remains. (Photo Courtesy Scott Tiemann)

 

Step-10: Align Remaining Panels

10As mentioned earlier, the driver’s side of this Judge was worse off than the passenger’s side, requiring an extensive teardown and rebuilding with reproduction sheet metal. In this case, the extent of the rust damage was far beyond a quarter-panel patch, and therefore the entire quarter panel needed to be replaced.

Before you cut off the rear quarter panel, align the panels that will still remain on the car. That way, you can properly align the replacement quarter panel when you’re installing it. (You don’t want to find out after you installed the quarter that the trunk lid and door were not properly aligned and have unsightly gaps between your new quarter panel and adjoining parts.) Start with the front fender and make sure the gap and alignment are even with the front seam of the door, and also make sure the trailing edge of the door properly aligns with the existing quarter panel. Once that has been accomplished, you can move onto cutting out the quarter panel. The process was started with a cut along the factory seam. (Photo Courtesy Scott Tiemann)

Step-11: Drill Out Factory Spot Welds

11Rust has ravaged the driver’s side of this Judge. Corrosion has destroyed the entire quarter panel, and the inner wheel well has extensive rust damage. Essentially, this entire area of the body must be reconstructed. Having such a valuable car cut up like this may look intimidating, but that’s what it takes to build a show winner out of a rusty car. When rust damage is this extensive, the repairs are substantial, but you need to take a planned, methodical, and patient approach to install each body part. The inner wheel­house, the trunk floor, outer wheelhouse, and then the full quarter panel will be replaced and/or repaired in that order.

If you have this level of metal deterioration, drill out the fac­tory spot welds to free up the quarter panel. Use a cutoff wheel to cut through the original spot welds on the edge of the panel. Cut off the quarter panel at the trunk lid frame, the deck panel, and interior-side bulkhead panel. In addition, cut off a portion of the trunk adjoining the wheel well. Fabricate a patch for this area of the trunk. The tools you use to make the cuts are dictated by the amount of space available and could be a small or large cutoff wheel, plasma cutter, air chisel, or spot-weld drill bit. (Photo Courtesy Scott Tiemann)

Step-12: Inspect Wheel-Well Housing

12A close inspection revealed that the outer wheel-well housing was damaged, wrinkled, and rusted to the point that it needed to be replaced. However, the inner half could be saved with a patch similar to that on the other side. This side of the trunk floor must also be replaced with reproduction sheet metal. (Photo Courtesy Scott Tiemann)

Step-13: Sandblast Support Bracing

13If your trunk support bracing is structurally solid, carefully sandblast and prepare it for reassembly. If the bracing underneath is in good shape, retain it and weld the new trunk floor section to it. (Photo Courtesy Scott Tiemann)

 

Step-14: Remove Rust Behind Quarter Skin

14Carefully use a sandblaster to remove the rust from the panels behind the quarter skin. This provides for a good foundation for the rust-inhibiting primer and paint. Here, the trunk and rear bulkhead body structure are solid and free of corrosion. But if your particular GTO has more rust in this area, all of it must be removed from the panels and body. If the rust isn’t completely removed, it will start coming through the sheet metal, and eventu­ally, the body work must be re-done. (Photo Courtesy Scott Tiemann)

Step-15: Weld In New Trunk Floor

15Weld the new trunk floor section into the good metal. Spend the time to make sure the trunk floor section is in proper alignment with the adjoining panels and the seams properly line up with rest of the trunk floor. The outside edge of the trunk patch has a lip stamped into the reproduction trunk panel. Weld the trunk patch to the existing trunk section using a butt joint. Use a set of welding clamps to keep the pieces in alignment and promote good spot welding. Once again, drill the panel and use tack welds to attach the patch to the trunk sup­port members. Place spot welds every 3 or 4 inches to secure the panel to the trunk brace. (Photo Courtesy Scott Tiemann)

Step-16: Install Inner Wheel-Well Patch

16Using high-quality reproduction parts, you can cut the patch from an inner wheelhouse. That way the contours match perfectly to the inner wheel-well sheet metal. It’s far easier to cut repro­duction body parts down to size than to fabricate a patch piece out of raw sheet metal. First, measure the patch for the butt weld. Then spot weld the patch to the inner and outer wheel well. Grind the spot welds flush to the sheet metal. The inner wheelhouse pictured here had a patch welded in as on the other side. (Photo Courtesy Scott Tiemann)

Step-17:Install Inner Wheel-Well Patch

17Using high-quality reproduction parts, you can cut the patch from an inner wheelhouse. That way the contours match perfectly to the inner wheel-well sheet metal. It’s far easier to cut repro­duction body parts down to size than to fabricate a patch piece out of raw sheet metal. First, measure the patch for the butt weld. Then spot weld the patch to the inner and outer wheel well. Grind the spot welds flush to the sheet metal. The inner wheelhouse pictured here had a patch welded in as on the other side. (Photo Courtesy Scott Tiemann)

Step-18:Install Inner Wheel-Well Patch

18Keep as much original sheet metal as possible. Tack weld the wheelhouse piece into place and then finish with a MIG welder. Then smooth it with a sanding disc so it looks like a fully integrated piece. (Photo Cour­tesy Scott Tiemann)

 

Step-19: Hang Quarter Panel

19At this stage, the inner wheelhouse has been repaired, the outer wheelhouse has been replaced, and an adjoining section of the trunk has been replaced. Hence, all the body work for the wheelhouse and adjoining parts have been completed. Now it is time to hang the quarter panel itself. Drill the quarter panel front to rear with 1/8-inch holes every 6 inches or so to secure it to the upper quarter. Locate the full quarter panel with bolts, tack weld, and then finish welding it in. As with the previous sheet-metal installations, the results lined up perfectly in this example. (Photo Courtesy Scott Tiemann)

Step-20: Locate Data Tag

20The Judge’s original data tag was removed to prevent damage while the bodywork was performed and also to prep the area under it for paint. New, correct rivets to re-attach it are available from TrimTags.com. While it is legal to remove the data tag for the purposes of restoration, removing a VIN tag riveted to the body, as in the early GTOs, is a federal crime. Don’t do it. (Photo Courtesy Scott Tiemann)

 

Step-21: Avoid Painting Over VIN

21The VIN of the car is stamped into some body panels, and it is often hidden to thwart theft. It is important when painting these areas to not have the paint obscure these numbers. (Photo Courtesy Scott Tiemann)

 

 

Step-22: Select Paint

22Rust inhibiting paints, like Hirsch Miracle Paint, act as a barrier to moisture, com­pletely encapsulating the metal. Some of these paints are affected by UV rays, so a topcoat is needed in some cases. (Photo Courtesy Hirsch Automotive)

 

 

 

 

 

Step-23:Pull Dents

23Years ago the only option for pulling out a dent in a body panel was to drill holes in the panel so a slide hammer could be attached. Once the dent was pulled out with the slide hammer, the holes needed to be filled in with lead or body filler. And that was a hassle. Today, this handy stud welder is a great way to fasten a stud to a damaged panel, making slide-hammer attachment a snap.

 
LSB


 

Place a stud into the welder, touch the bare metal within the dent, and pull the trigger. The stud is instantly welded onto the panel. Best of all, there isn’t enough heat generated to warp the panel and once completed, the stud can be ground off and the surface primed. (Photo Courtesy of Eastwood Company)

 

Quarter Panel Patch Preparation

 

0Time and corrosion have taken their toll on this driver-side quarter panel, and as result, replacement is the most viable option. The recipient of the quarter-panel patch installation is this 1967 GTO hardtop, which is owned by Tom DeMauro, editor of High Performance Pontiac magazine. Tom purchased the Goat back in 1987, and it is a typical rust-belt machine. Years of exposure to salt and corrosion requires a quarter-panel replacement. While this GTO doesn’t have a particular pedigree, Tom has a great amount of affection for it, so he invested the money to have the quarter panel repaired. The car has many high-performance upgrades, so it runs, handles, and stops better than a stocker. However, it obviously needs some help in the body and paint departments. Tony Golem­breski at Melvin Benzaquen’s Classic Restorations in Sloatsburg, New York, replaced the rotted-out rear quarter.

00A thorough and careful inspection of the rear quarter panel from underneath the car, the trunk, and from the wheel well shows the extent of rust damage. This outer wheel­house is rusted through and cracked. You can also see that the lower quarter-panel skin is rusted through right above the trim panel. Once the trim panel was removed, more rust was found beneath it. The trim panel trapped moisture in the quarter panel and rusted out the metal as it always does. But the rust didn’t stop there it extended back and around the car and underneath the taillights. These rust patterns are very typical of an East Coast or Middle Atlantic GTO. Quite a bit of body filler had been added to this quarter as well, as a previous owner tried to repair it, and the repair job was marginal at best.

Step-1: Cut Off Quarter Panel

1To cut off the quarter panel that extends underneath the rear bumper, the bumper itself needs to be removed. Remove the four bolts holding the bumper to the bumper bracket. Remove the bumper to access the rear of the quarter panel. If the bolts are rusted solid, the heads can be ground off with a rotary grinder.

 

Step-2: Remove Bumper

2Once the bolt heads are ground off, the bumper comes off easily. If your bumper is still very straight and the fit is excellent, it can be re-chromed and reused.

 

 

2aThe replacement sheet metal includes this stamped lower rear  quarter-panel patch, trunk extensions, and outer wheelhouse. The pieces are available from Original Parts Group (OPG). While the parts are all stamped from correct-gauge sheet metal, the quarter-panel patch and trunk extension need some modification to fit properly.

 

2bThe inner wheelhouse is also from OPG, and like the others, it is close to the factory origi­nal, but not the same exact part. These repro­duction parts just need some time and fit work to be properly installed in position.

 

2cThis lower quarter panel was not stamped from factory dies, and therefore, it is not an exact replacement. Consequently, a piece such as this often requires some trimming and fitting to be installed on the car because it’s marginally different than the original.

 

Step-3: Remove Lower Quarter Molding

3Remove the factory lower quarter molding. If very little of the quarter molding actually holds the piece on, it can be pulled away. Commonly, the clips must be released with a trim tool, but it simply wasn’t necessary here, as the molding was barely attached to the quarter panel.

Step-4: Remove Trim Piece

4Pry off the trim piece to the quarter panel. Moisture may be trapped behind the trim piece, with the expected corrosion eating up the lower portion of the quarter, trunk extension, and outer wheelhouse. If rust has come through along the entire length of the quarter panel, there is too much corrosion damage to do a simple body-filler patch. The rust-affected quarter panel and wheelhouse must be cut out and replaced.

Step-5: Align Quarter Panels

5Test-fit the panel. Use a wide-jaw locking pliers to keep the body panel in place. Use a scratch shawl or a Sharpie pen to mark the original piece along its entire length. Reproduction panels and even NOS panels often don’t fit the same exact way as the factory-original panel.

Align the top quarter panel with the lower quarter panel and be sure it aligns with the wheel-well opening and the seam at the bumper. Gaps along the edges are common. If the panel is too short in any area, use a piece of metal from the old quarter panel or cut a piece of sheet metal from the same-gauge sheet metal and tack weld it in place. With diligence and practice you should be able to fit most panels. If you get stuck in a particular area, take some digital photos of it and take them to a respected body man or enthusiast; he can often help you find the best solution.

Step-6: Place Tape for Quarter Panel Cut-Off

6Once you verify the size of the quarter panel, scribe a line along the factory quarter panel, using the upper edge of the quarter-panel patch as a guide. Place a piece of tape to run the entire length of that line. When the sparks start flying from the cutoff wheel, it’s hard to see the scratched or marked line. The tape gives an easy-to-see reference point for cutting off the bottom of the quarter panel.

Step-7: Use Rotary Tool to Cut Off Quarter Panel Skin

7ake your time and use both hands to get a straight, clean cut along the axis of the quarter panel. Be sure you use the proper safety equipment when performing this procedure. Use a grinding wheel to cut the section of the quarter panel to be replaced by the patch panel. A 3M general purpose 3-inch cutoff wheel, or similar wheel, allows you to precisely cut through the sheet-metal skin. Be sure that your compressor can sustain 90 psi for the duration of the cut. Also be sure to use proper hand and eye protection, as metal cuts can be very serious.

Step-8: Remove Rusted Lower Quarter Panel

8Use a rotary cutoff wheel to remove the rusted lower quarter panel. It takes some skill to do this procedure properly. Practicing on scrap metal is a good idea, or you can have someone with experience show you how. With a clean and straight cut, the rest of the panel can now be removed by drilling out the rest of the tack welds. Use a MIG welder to butt weld the bottom replace­ment panel to the top quarter panel. The panel is welded to the wheel-well lip and around to the bumper section.

 

Patch Panel Installation

 

Step-1: Cut Around Quarter Panel Lip

1Carefully use the cutoff wheel to cut around the quarter panel lip. Once that is done, you can pull down the quarter panel. Over the years, a lot of moisture and debris has collected inside this quarter panel. On the bottom of the quarter panel, drill through the tack welds and remove the quarter panel, along with all of the debris collected in the sump formed by the trunk extension.

Step-2: Fit Trunk Pan

2With the quarter panel removed, you have access to the trunk and can test-fit the trunk pan extension. This piece ended up needing a fair amount of work in the rear to line up correctly.

 

 

Step-3: Punch Holes in Patch Panel

3An air punch is a commonly used body shop tool and makes 1/2-inch holes every 4 or 5 inches along the outer perimeter of the patch panel. If you cannot afford to rent this tool, hand drill these to make the panel fit, so it can be securely fastened to the remaining quarter panel.

 

Step-4: Use Grinding Pad to Remove Material
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Use a 3M (or similar) grinding pad to remove paint, old body filler, and rust. While this takes some time and patience, it’s relatively easy work, so apply even pressure and move the disc around the panel. Avoid generating too much heat in any one area because this could warp the panel. Once the panel is down to the bare metal, this helps ensure the weld will successfully join the two pieces of metal.

 

Step-5: Fit Patch Panel

5Clamp the panel to the car and align it in its proper position. Install the sheet-metal screws through the bottom of the quarter panel and into the quarter-panel extension. Once secured to the quarter-panel extension, the patch can hang there until the next step is completed. Install the 14 screws on the top portion, including two behind the rear bumper area, as well as five on the lower section that meets the trunk extension.

 

Step-6: Fabricate Flange on Patch Panel

6Use an air-powered flange-making tool to fabricate a flange that provides a better mating surface because an overlap joint is created rather than a butt joint. The tool slightly stretches the metal so there is a slight joint overlap for added strength. At-home restorers may be able to rent a flange tool if buying it does not make sense. If you cannot access this tool, a hammer, dolly, and anvil can be used to create the same flange, but it takes more time and some skill to develop the flange by hand.

A MIG welder can create a lot of heat during the butt-weld process, and as a result, can warp the body panels, which is a very bad thing. Therefore, make sure the welder is set on a low-voltage setting for welding thin sheet metal and give each spot weld a chance to cool before placing another spot weld.

Step-7: Fit Patch Panel

7Place the lip of the quarter-panel patch over the flange on the top panel. Drive sheet-metal screws through the patch panel into the factory quarter. After the patch panel has been anchored to the top panel, check it for fit. If you look closely, you can see this patch panel has a stamped flange. It was not used for two reasons. First, it is too shallow to be useful. Second, and more important, it could potentially allow moisture to collect around the welds, as the bottom edge of the factory quarter goes over the patch panel, leaving the back side exposed for water to accumulate. Position the patch, tack the panel in place, and completely cover the edge with a bead of weld. The stamped-in flange is shallow enough to be completely covered with a light coating of filler. Then unscrew the quarter-panel patch and set aside.

Step-8: Shape Patch Panel

8Use a hammer and dolly to shape the contour of the patch panel so it follows the contour of the factory quarter. If you haven’t spent much time working metal, firmly hold the dolly behind the metal and patiently work the metal into the desired shape. Smaller, focused blows are needed to shape the metal, rather than large, heavy blows. Remember, metal working is an acquired skill and you may need to spend some time developing these skills before attempting to shape a patch panel. You can hone these skills by working scrap metal on a bench, taking a course in metal working, and/or refer to Matt Joseph’s books Automotive Body Work and Rust Repair and Automotive Sheet Metal Forming and Fabrication.

Step-9: Inspect Passenger Quarter Panel

9The factory passenger’s side does not match the patch on the driver’s side, so you must correct the difference and get both sides into similar configuration.

 

 

Step-10: Adjust Driver-Side Quarter Panel

10Make a vertical cut about 2 inches long on the top edge of the trunk floor extension, then fold the trailing edge forward and fabricate a small patch to fill the void between the extension and the rear end body panel.

 

 

Step-11: Align and Clamp Inner Wheelhouse

11Align the inner wheelhouse to the rear trunk exten­sion panel and clamp once the desired position is determined. In order to align the inner wheelhouse to the rear trunk extension, cut the leading edge of the wheel­house and bend it upward to meet the trunk extension. Once bent and raised into position, clamp it.

 

Step-12: Fit Patch Panel to Trunk

12Cut a small patch from sheet metal and then clamp it to the trunk patch with body-work pliers. Tack-weld the extension into place. It was made to join the trunk floor extension to the rear end body panel.

 

 

Step-13: Measure and Fit Outer Wheelhouse

13If the outer wheelhouse is rusted through and cracked, you want to keep as much of the original sheet metal as possible. Measure the section that needs to be replaced. Apply those measurements to the repro­duction wheelhouse, and then use a cutoff wheel to cut it off. Allow for no less than 1/2 inch of overlap.

 

Step-14: Install Wheelhouse Patch

14Once measured, use metal shears to cut a precise edge. Then place the wheelhouse patch into posi­tion and verify the fit. When in the proper position, drill a hole in the top right-hand corner and then screw the patch into the trunk patch or the inner wheelhouse.

 

Step-15: Anchor Outer Wheelhouse to Trunk Patch Panel

15Drive a sheet-metal screw through the outer wheelhouse and into the trunk patch panel, so it is held into position for welding.

 
 

Step-16: Weld Quarter-Panel Body Parts Together

16All the adjoining parts are now fitted up, screwed together, and ready for welding. Here you can see the outer wheelhouse trunk patch and the inner quarter panel. All of these components have now been properly fitted so the quarter panel skin can be reinstalled for welding.

Step-17: Test Fit Quarter Panel Patch

17Use three sheet-metal screws to re-fasten the lower quarter panel to the top quarter panel and over the wheelhouse patch and trunk extension under it for another test fitting. Make sure the panels properly align, so all the pieces of the jigsaw puzzle now fit into place. Now that the test fit has been success­ful, remove the quarter-panel skin again, so the outer wheelhouse and other parts can be welded. Depending on the model year of your GTO, you could temporarily reinstall some of the trim pieces to further verify the alignment of the panels prior to welding.

Step-18: Weld Quarter Panel Pieces

18Use a MIG welder to place a bead of weld on the outer-fender housing and the adjoining inner-fender housing. When stitch welding the outer-fender housing, manage the application of heat when placing the bead weld on the seams. The selection of the welder settings is paramount. You want enough amperage and heat to have the weld properly take hold but not blow holes in the metal. Conversely, you don’t want it too cold to have the welds fall off. Show me three 1967 GTOs and I’ll show you three different settings for both plug welds and stitch welds. Using the rusted quarter-panel section that was removed as a test for the proper amperage settings is the best way to determine what the best settings are for a particular car.

Step-19: Weld Wheelhouse to Trunk Extension

19Weld the trunk extension to the inner wheelhouse. Apply a bead of weld along the seam, a few inches at a time, and allow it cool, then switch to the opposite side of the seam to spread out the heat. Welding thin sheet metal is a delicate art so the proper welder settings are important. Be careful not to burn through or warp the panels. Then weld the cut to solidify the new contour of the trunk extension.

Step-20: Weld Wheelhouse to Trunk Extension

20Weld the small patch joining the trunk extension to the rear-end body. Place a full bead on the patch and the inner quarter panel to secure it in position.

 

 

 

Step-21: Weld Trunk Extension to Trunk Floor

21Stitch weld the top edge of the trunk extension to the trunk floor. The panel provides the necessary support to the trunk floor.

 

 

Step-22: Weld Trunk Extension to Trunk Floor

22Weld the trunk floor to the inner quarter-panel support, providing additional strength and improved structural integrity. Your newly welded panels should be straight because they didn’t warp or bend from the over-application of heat. Stitch welding is very forgiving in this area and practicing on scrap metal beforehand gives some insight into the proper settings for each phase of the operation.

 

Step-23: Place Stitch Welds on Inner Quarter Panel

23These stitch welds are at the back of the inner quarter panel. Be careful not to apply too much heat and warp the panels.

 

 

Step-24: Grind Down Welds on Seam

24A rotary air grinding tool grinds down the welds to develop the smoothest surface possible. You want to shape the body panel and leave behind the smoothest and most correct profile possible. This is done in prepara­tion for applying all-metal body filler. Grind the welds, not the surrounding metal.

Step-25: Apply Body Filler to Inner Quarter Panel

25Body filler should not come in contact with your skin so put on a pair of nitrile gloves. When preparing body filler for application, be sure that the filler and hard­ener are thoroughly and properly mixed. If the filler doesn’t have enough hardener, it does not dry properly. If it does not dry correctly, many problems may result. The filler doesn’t have a strong bond with the metal, and therefore the primer and paint don’t adhere to filler properly. The filler could absorb moisture and rust later on.

Many filler products need to be mixed, while other products are premixed. Once mixed, use the filler to cover the welds as well as to smooth and seal the area. There are number of products that are suitable for this type of body work. You can use all-metal filler, which contains aluminum, and as a result is stronger than regular body filler. All-metal filler is ideal for metal leveling and it can be used on aluminum as well as sheet metal. When applying body filler, apply the thinnest coat to cover the area. With most body work, the body filler should not be thicker than 1/8 inch.

Step-26: Prepare Quarter Panel Patch for Installation

26Use a wire brush to clean the quarter-panel patch. A vertical dent was discovered on this particular panel. It appears to have been made during the stamping process. If you look at the right side of the patch below the seam, you can see the dent. To true-up the panel, a hammer, dolly, and some blunt force trauma were used to bring it back into shape.

Step-27: Shape Quarter Panel Patch

27Remember, metal working is an art. To get the quarter-panel patch back into shape, use a medium metal-finishing hammer and a medium dolly loaf on the backside. The loaf needs to follow the profile of the quarter-panel patch and the hammer has a convex face for working the metal. Use small, firm taps rather than heavy blows to slowly bring the area back into shape. Rushing it can do more damage. This kind of straightfor­ward and easy repair job can be performed on a milk crate placed on the floor. But it is easier and more comfortable to manipulate the hammer and dolly on top of a bench.

Step-28: Align Quarter Panel Patch

28The quarter-panel patch has been test fitted to the car several times, so it should align with the welded inner quarter panel, trunk patch, and wheelhouse patch. Prop­erly align the panel as you did before, and then drive sheet-metal screws through it to hold it in place. Here, four screws fasten it at the trailing edge of the panel.

 

Step-29: Shape Quarter Panel Patch

29Even though quite a bit of panel fitting has been performed, the quarter patch may not line up perfectly. Use the pick end of a finish hammer to move the metal around, so the patch-panel edge lines up with the factory quarter. Hold the dolly in your right hand from inside the trunk and lightly tap the sheet metal until both seams come into alignment. Once again, be patient and take the time to do it right. One small move at a time shapes the metal and eventually you achieves the finished shape.

Step-30: Tack Weld Quarter Panel Patch

30Weld the patch panel to the vehicle in two major steps: tack weld and then stitch weld. First, place tack welds all along the seam of the quarter-panel patch to firmly anchor it in position. Place a tack weld every 3 inches and quench the weld with air to cool the area and prevent warping. MIG welders can apply too much heat and warp the panels if you’re not careful. Grind off the heads of the tack welds; they don’t need to be flush.

Step-31: Tack Weld Quarter Panel Patch

31Once the tack welds have firmly anchored the patch panel into position, enlarge them so they are nearly together. This once again manages the heat application during welding and helps prevent warpage. Once the second round of tack welds is placed, go ahead and connect all the welds with a stitch weld to fully close the gap between the two pieces of metal.

Step-32: Tack Weld Quarter Panel Patch

32The stitch welds connect the tack welds and a full bead is starting to form. Together, they locate, secure, and seal the panels, becom­ing one piece.

 

 

 

Step-33: Patch Inner and Outer Wheelhouses

33A majority of the work has been completed the quarter-panel patch, but a patch panel is also needed for the rusted areas of the inner and outer wheelhouses.

 

 

Step-34: Cut Patch Piece for Inner Wheelhouse

34This is probably the most complex and difficult step of the quarter panel patch job. After you cut the desired piece out of 16-gauge sheet metal, it needs to be formed to the profile of the wheelhouse. Use an English wheel to stretch and form the sheet metal piece to the profile of the outer wheelhouse. (For more details on this process, refer to Automotive Sheet Metal Forming and Fabrication by Matt Joseph). Once the piece has been test fitted and the fit verified, the rusted sections need to be cut out using a cutoff wheel. The new metal can then be clamped into place.

Step-35: Tack Weld Wheelhouse

35The wheelhouse patch needs to be welded into position. To do that, drill three 1/16-inch holes through the patch panel into the trunk extension and lower inner quarter panel. Place three plug welds to connect the outer wheel patch to the trunk extension. During the plug weld process place the welds in the panel and quickly quench with air to prevent warping.

Step-36: Tack Weld Wheelhouse

36This close-up shows the tack welds that join the wheelhouse patch to both the trunk extension and the quarter-panel patch.

 

 

 

 

Step-37: Tack Weld Lower Quarter Panel

37At this point, the entire rear quarter-panel section is coming together. These integrated parts provide body integrity and clean lines. Once the work is completed, it will look as it did when it came from the factory. Drill holes through the lower quarter-panel patch and into the trunk extension. Then place plug welds through the quarter-panel patch every 3 inches.

 

Step-38: Grind Down Tack Welds

38Use the rotary air tool with a 60-grit sanding pad to grind down the tack welds, preparing it for final finishing. Then grid the welds smooth for the entire quarter-patch panel. Be careful not to spend too much time grinding in one area and move the grinding tool down the seams. This way excessive heat is not produced and the panels do not warp.

 

Step-39: Smooth Panel Seams

39At this stage, welds have been ground flush to the quarter panel. This is the final metal-working stage before you apply thin coats of body filler. You want the surface to be as smooth as possible. If the welding and grinding has been correctly completed, you just need a thin coat of body filler. Often, novice body workers haven’t properly installed the panel, completed good welds, or smoothed out the welds. In turn, an excessive amount of body filler is used to correct these mistakes. Eventually the whole job comes undone because a thick coat of body filler often shrinks, cracks, and then rust forms. You need to ensure that all steps have been correctly completed because the outer appearance of your car (i.e., the paint) is only as good as the body work underneath it.

Step-40: Smooth Panel Seams

40The quarter-panel patch has been fully prepared for body filler. The seam has been tack and stitch welded and then the seam has been smoothed over. Notice how well the upper quarter panel and the patch align with each other. With a patch like this, only a small amount of body filler needs to be applied, and therefore you need not be concerned with shrinking or cracking of the body filler.

 

Step-41: Apply Body Filler Base Coat

41A variety of body fillers are suitable for this type of work. Just be sure the filler and hardener are properly mixed before applica­tion. Use the straightedge applica­tor to apply two thin coats of filler. Here, Real Metal body filler is applied for the base coat. Try to apply as thin a coat as possible. Your body filler should be no more 1/8-inch thick or you may run into shrinking and cracking problems. Applying it too thick ends up with a lot more sanding later.

Step-42: Apply Body Filler Final Coat

42Use a lighter, smoother filler for the top coat. You can clearly see the ridges of the filler, but blocking removes these ridges and produces a smooth profiled final finish. Block sand the base coat with 120-grit sand paper. As a rule, the coarser-grit sandpaper shapes the body filler, while the finer-grit sandpaper smooths the body filler. Often, using a dual-action (DA) sander is an alterna­tive to sanding blocks and other tools. The DA can be used in a rotary or orbital motion.

Step-43: Block Sand Body Filler

43Block sanding thins the filler to provide a smooth, uniform surface and a suitable foundation for primer and, ultimately, the final top coat. While every stage of the repair is important, this stage is critical and many body techs spend a lot of time smooth­ing and shaping the surface. Primer can fill small imperfections in the filler, but the filler surfaces need to be as smooth as possible. For the top coat, use 240-grit sandpaper for a smooth flat surface area and then use 320-grit paper to eliminate any small surface imperfec­tions. It is easier to shape and smooth the body filler before it’s completely dry.

Step-44: Cross Sand Body Filler

44Cross sand the body filler until it feathers into the bare sheet metal and looks like one smoothly flowing surface. Use a 14-inch sand­ing block with 120-grit, then switch to 240-grit, and finally 320-grit to provide a fine surface finish.

 

Step-45: Spread Top Coat of Body Filler

45Mix body filler and spread it across the upper quarter and lower quarter patch panels. Apply the top coat as thin as possible, and apply a spot coat. Use the same 14-inch sanding block. Start with 120-grit, switch to 240-grit, and end with 320-grit for a smooth surface finish.

 

Step-46: Apply Body Filler to Trunk

46

Also apply a coat of protective spot coat to the trunk. In addition to protecting the back side of the weld, the spot coat goes a long way toward hiding the repair. Sanding should also be done on the back side but it but does not need to be as perfect as on the outside.

 

Step-47: Apply Body Filler to Bumper Area

47Apply the filler with a straightedge in a smooth and linear fashion, a clean sweeping motion that covers the entire area to be filled in one carefully-placed application.

 

 

Step-48: Mix Primer

48The primer used as a guide coat is regular old spray-bomb sandable primer. Why is it okay to use such a cheap primer out of a can? Because it is used not as a base for any paint but rather as a way to visually inspect the panel for high and low spots and other imperfections. It also dries very quickly, so sanding can begin without much waiting time. Completely sand off this primer, re-apply, and sand off again multiple times in the block sanding process.

In a home restoration project, it doesn’t make a lot of sense to invest in high-end primer at this stage of the process. When the block sanding is completed and the panel is free of imperfections, consult your body shop manager to select a primer that works with your chosen paint system. Follow the manufacturer’s instructions for mixing the primer. Use the proper measuring cups to achieve the optimal ratio. This is something you cannot guess at. After measuring the correct primer and element, thoroughly mix it so it’s properly blended.

Step-49: Apply Primer Guide Coat

49Spray a primer guide coat so the high and low spots of the paint can be identified. If major flaws or imperfections are revealed, you may have to use spot body filler to fill in the low areas and then sand it out and prime it again. Spot putty is essentially the same as most primers but has a thicker paste-like consistency. Use it to fill chips, low spots, sanding scratches, and other imperfections in the primer. Apply it in much the same way as filler, using a small flexible squeegee; the coat is much thinner. Block sand to match the contour of the surrounding primer surface and then cover again with primer.

Measure, measure, measure. When positioning the new quarter panel into place, take note of how the new panel aligns with other adjoining panels and their contours, the outer wheelhouse, bumper, and other critical points. It is not difficult to install a quarter panel a little too high or low and throw off everything in the process.

Rust Preventers

Before you replace the quarter panel (and anytime that you run into areas hidden by outer sheet metal or interior pieces), it is a great opportunity to prep the metal with a rust preventer that seals the metal from the elements.

There are three brands that are quite similar in formulation and in application, POR-15, KBS Coatings, and Hirsch’s Miracle Paint. While all can be thinned enough to run through a paint gun, this is one time that brushing is acceptable, as these products dry smooth without brush marks. Once dried, they offer an incredibly tough coating that gets stronger if exposed to moisture. Some are sensitive to UV light and may need a top coat if exposed to light. Check with the manufacturer for specifics.

Dent Removal

With many books on bodywork and dent removal, I am not going into too much detail here. I recom­mend picking up a copy of CarTech’s How to Paint Your Car on a Budget, by Pat Ganahl, as it covers that topic in much more depth than space allows here.

That being said, simple dent removal requires appropriate tools. There are almost as many types of body hammers as there are dents to repair. Eastwood has a full line of body hammers that make it easy to remove dents in areas where you can get behind them and pull or tap them out.

In the past when you couldn’t get behind the dent, holes were drilled in the panel and a slide hammer was inserted to pull the dent out. The idea was that it was easier to repair a couple of small holes than it was to take apart a car far enough to expose the back side of a dent.

That mindset still holds true today, but there is a really great little tool that makes the job easier and it is a lot easier to fix the damage. The tool is a portable stud welder, mar­keted by Eastwood, H&S Auto Shot, Harbor Freight, and others. With a stud inserted and the trigger pulled, it instantly spot welds a stud onto a dented panel, provided the paint and any surface contaminants are removed. From there, a slide ham­mer is connected to the stud and the dent can be pulled out in the normal fashion. Once the operation is com­pleted, the stud can be ground off the panel with little or no warpage.

Filler

In the old days, lead was the pre­ferred material for body filler. Expe­rienced body men found it was easy to work with. It flowed nicely and was fairly hard when cooled. It took primer and paint like the rest of the body and when done correctly, lasted for the life of the car. Unfortunately, lead is poisonous, heavy, expensive, and did I mention poisonous?

Today, plastic fillers offer the same positive qualities of lead with­out the weight, high cost, and health risks. They can give varying amounts of shaping and hardening times and are clearly the preferred choice.

When using fillers to level off dent repairs or grinding marks in sheet metal, the rule is, less is more. If you need more than 3/16 inch of filler, it would be wise to go back and keep working on the dent or repair in order to bring it closer to level. This way, the filler is less prone to crack, craze, or separate from the parent metal (see Chapter 4 for more details on body filler).

Body Tags

This subject really makes me uncomfortable because there are legal ramifications involved with the removal of tags from a body. While it is legal to take off a data tag to pre­pare the area under it for paint or to repair rust, it is not legal to take a VIN tag off a car. It is actually a fed­eral crime to do so.

If the area around your data tag is not rusted or damaged, it would be a wise move to leave it where it is and very carefully soda blast the area. If it needs to come off, pho­tograph it first. With a pliers, care­fully pinch the rivets to decrease their diameter, allowing them to be pushed through the hole so you can remove the data tag. Once the tag is off, put it somewhere safe, like a safe deposit box. The last thing you want is for it to get lost, as your car’s heri­tage will be in question for eternity if it is.

When it is time to reinstall it, use the correct rivets and a rivet gun from TrimTags.com and apply some adhesive seam sealer in the center of the rivets to replicate the factory preparation.

Collision Damage

If your GTO has a significant amount of collision damage, enough to require a frame straightener or hydraulic rams to bring it back into shape, take it to a collision shop for repair. These shops have the frame-straightening jigs and a variety of tools to professionally repair colli­sion damage, and this is industrial equipment the at-home restorer can­not afford. Of course, there are peo­ple who have successfully pulled out crumpled tail panels and quarters at home, but in my opinion, these are repairs that are completely out of the scope of a home restoration. Doing it wrong will at best worsen the damage and at worst make the vehicle unsafe.

If your GTO has been rear-ended, T-boned, or has taken a front-end hit hard enough to bend the frame rails, you owe it to yourself and any­one who rides in your car to make sure it has been accurately straight­ened. With the latest generation of laser-guided frame-straightening equipment, there is no excuse for a car that crab-walks down the high­way or one that the body panels cannot be properly aligned because the frame is not square and true. The money you spend to have it done right by trained professionals is money well spent.

 

Written by Rocky Rotella and Posted with Permission of CarTechBooks

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