The quality of the bodywork is a telltale sign of the quality of the restoration. Regardless of what level of restoration you undertake, you want to achieve professional results. The body needs to resemble the original bodywork, and be free of rust, dents, and damage for years of faithful service. Beyond components such as moldings and glass that can be replaced or refurbished, the condition of the body and paint has the greatest impact on the car’s appearance. (Because these are substantial aspects of restoration, I devote a separate chapter to each of these topics.)
This Tech Tip is From the Full Book, HOW TO RESTORE YOUR MUSTANG 1964 1/2-1973. For a comprehensive guide on this entire subject you can visit this link:
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In this chapter, I address some basic repairs, such as fixing dents and rust, and installing panels. While there is naturally some overlap with Chapter 4 on paint when it comes to things like using body filler, I have kept this chapter focused on just the body, rather than on its subsequently coatings.
Most enthusiasts who attempt such repairs either already have some experience doing them or are being guided by someone who does. So I must be perfectly clear: Bodywork is not for the inexperienced. It requires certain types of expertise and specialized equipment that most people don’t have. I’ve tried to highlight some of the steps that need to be taken to get the best results for a daily-driver or a weekend-cruiser project. Those pursuing the higher standards of a show car will probably have to go beyond what I can cover here. Such projects are almost always done at the professional level.
Regardless of your project level, this chapter will help ensure the work is done properly and the repairs last a long time, with minimal fear of future problems. I cover some of the more common approaches to repairing rust, small imperfections (dents, for example), smaller more-complex areas, and larger moresimply- shaped areas. These procedures should translate to most areas of the vehicle, even though I show specific parts.
First, I cover the basic steps in removing rust from a solid part or panel prior to sealing and/or priming in preparation for paint. This common process can be applied to virtually any part of the car with minor adaptations for a particular situation.
Then I cover three types of repairs— small area, large area, and dents/dings— and the work required to repair or refurbish each one, so it can be sealed and/or eventually primed for paint. These basically involve the repair of severe mechanical damage, as opposed to simply the repair of the surface of the metal. The goal of each is to repair the severe damage by removing, replacing, and/or reshaping the damaged metal. The repairs are then sealed and prepared as with surface rust repair. (Subsequent filling, smoothing, priming, and painting will be covered in Chapter 4.)
Minor/Surface Rust Repair
The cardinal rule when repairing rust damage is to not just treat the symptom (the rust) but to also treat the disease (whatever caused the rust). This seems simple enough, but it can take considerable detective work to figure out how moisture got to the affected area. The bottom line is there is no point in making a repair that you only have to make again because you didn’t eliminate the cause of the rust problem. (In this section, I only cover what to do after you’ve identified and fixed the cause.)
One of the first things to determine is why you are getting rid of the rust. Is it mostly for aesthetics or is there a more functional aspect to it? Many large, heavy/thick underbody parts normally develop a thin coating of rust that goes unaddressed because it has no real functional effect, in most cases. True, given enough time and additional moisture, any rust problem can eventually eat away at enough metal to cause a functional problem. Realistically, however, some parts of the frame, crossmembers, and suspension normally have a certain amount of rust that is tolerated. It’s not a serious concern because it doesn’t detract from the car’s value or functionality unless it becomes excessive. On a daily driver, you probably won’t address this. On a weekend cruiser, you want to clean this to your level of personal preference. On a show car, this has to go for sure, and the fix must be done at the highest possible level.
Rust in thinner steel parts, such as body panels and so forth, is almost always a problem because these areas tend to be more visible and, if they are structural to any degree, there is less reserve strength to keep the part from failing when it rusts. These parts also tend to allow water and/or dirt to get into areas where it is not wanted (interior trunk, etc.). Many early Mustang owners had to deal with water coming into the footwell area because of rust in the cowl vent and around the windshield. Water on your feet and a wet carpet (which can lead to rusted-out floorpans) is a higher priority than rust on the rear axle housing, especially for a daily driver.
Rust is never good, but the point is it may not automatically be bad enough to require the time and expense to repair it in every case. If the only benefit will be aesthetic, you may just want to simply treat it and paint over it.
If you’re trying to make a heavy part look better, such as a rear axle or control arm, you just need to remove the loose rust before applying your choice of coating( s). This can be done with a wire brush, by grinding, by media blasting, or even by chemical conversion in some instances. The key is that the texture of the surface is not a real priority in such instances; some pitting or surface roughness is considered acceptable. If you want a smooth-as-glass finish, that’s a whole different story. I won’t cover that process because it involves expensive finishing, such as powder coating.
For our project car, we’re dealing mainly with thicker, primarily undercar parts, where you first simply remove as much of the rust you can by physical and/or chemical means. There are numerous rust-removing solutions commercially marketed. Some are simply brushed on and left for a period of time before wiping off; some require immersion; and some actually remain on the part and chemically convert the rust into a protective coating that can be further sealed, primed, and/or painted. This approach can be used on virtually any rusted area that has not rusted through completely or has become severely pitted, including body panels.
Using The Eastwood Company line of products as an example, first wire brush, media blast, or otherwise remove the loose rust from the part. Then use either their Rust Dissolver or Rust Converter to chemically remove or convert the remaining rust. Which way you go depends on a number of factors. When dealing with a heavily functional, yet less-visible part, often the rust converter is the best choice for simply sealing the surface prior to painting. In the case of a thinner and more visible part, use the rust dissolver to remove as much rust as possible, to get down to bare metal.
Either approach works well; it’s often a choice based on budget or time. The rust converter approach is quicker and cheaper (in most cases) but will not provide as good a foundation for other treatment or repairs as the bare metal. If you intend to weld the metal, for example, you would use the rust dissolver approach and then use a suitable precleaner such as lacquer thinner or Eastwood’s PRE to remove any residue. A smoother surface simply requires more steps and preparation.
After you’ve either converted or dissolved the rust, it’s wise to seal the painted parts and bare metal surfaces against further rust. In either case, use Eastwood Rust Encapsulator or a similar product. This step provides extra insurance against future rust because it does a better job of sealing the surface than standard primers, which are mainly intended to provide a better surface for the topcoats to stick to. Sealing is not their primary purpose. When applied over the converted surface, you actually get a double benefit because both the converted surface and the Rust Encapsulator have sealing capabilities.
You also have the potential to effect a color change since the converted surface is always black, while the Rust Encapsulator is available in black, red, and silver formulations. Another benefit of Eastwood’s Rust Encapsulator is that it provides some degree of surface smoothing by filling small pinholes and similar irregularities. It can also be used either under or over body fillers; so if you want a smoother surface, you can use filler to get the smoothness you want and then seal both the metal and the filler.
Standard primers as well as lacquer, enamel, or polyurethane paints can be applied over the “encapsulated” surface (see Chapter 4 for more detail). Note, however, that it is also possible to simplyuse a sandable filler/primer over the encapsulated surface to provide an extra degree of surface smoothing capability, without having to resort to the use of body filler. In many cases, minor scratches and pitting can be successfully hidden due to the buildup qualities of the Eastwood Rust Encapsulator and/or the use of a sandable primer.
After you have the surface sealed and smoothed to the degree you desire, it can then be finished in any number of ways. For undercar and underhood areas, your most likely choice is to use a combination of coatings such as Eastwood’s Extreme Chassis Black and their Under Hood Black. There’s also Eastwood’s special, professionally oriented 2K Ceramic Chassis Black two-part coating that must be applied with a spray gun (the Extreme product is also available in aerosol spray can). Both Chassis Black formulations are available in either gloss or satin finishes, while the Under Hood product only comes in a 10- to 20-percent semi-gloss finish that’s correct for most radiator supports, innerfender panels, hood brackets, etc. The latter is available as both an aerosol spray or in one-quart cans. Eastwood claims these products outperform other automotive paints in terms of durability, resistance to chips, scratches, UV rays, and corrosion while also being resistant to most automotive chemicals. They also offer varying degrees of surface filling capability and are formulated to more easily allow multiple coats with fast drying times and to provide a superior finish.
Rust repair areas that will be finished in the same color as the rest of the body are treated the same as the rest of the body. The beauty of the repair process just outlined is that it simply removes and/or converts the rust you do not want, leaving behind a surface that accepts the same filler, primer, and paint you use on the rest of the vehicle. Of course you need to make sure you let the repaired area(s) dry/cure long enough before you apply the subsequent layers, but you need to properly prep the surface in any event. The ultimate goal is to not only remove/repair rust but also to do so in a totally invisible fashion so there is no trace of the work after the car is finished. This process restores a rusted surface so it can match adjacent, undamaged areas and thereby blend in more seamlessly with them.
Trunk Lid Repair Step by Step
MUSTANG RESTORATION: TRUNK LID REPAIR- STEP #1
The repair process begins by cutting away the outer metal skin, so we can remove the rust that has formed inside. In this case, it’s a thin section with the other metal close by. Many times you need to remove metal from around a cavity, such as the base of the door jamb, to get to the rust inside. This type of problem is very common when drain holes get plugged. We used a pneumatic cutoff wheel to carefully break through the outer skin without damaging the opposite side. In larger areas, such as floorpans, you can also remove the metal with plasma cutters, saws, etc.
MUSTANG RESTORATION: TRUNK LID REPAIR- STEP #2
After the outer metal skin has been removed, grind down any rough spots, so the patch panel you install sits more flush. You also want to get down to the bare metal to get a better welding surface. In this shot, you can also see the gap between the inner and outer skins in the left fastener hole. We believe this is how the water got inside to cause the rust. We’ll be sure to seal this properly later.
MUSTANG RESTORATION: TRUNK LID REPAIR- STEP #3
As you can see, we removed the majority of the loose rust, but we left some inside to prevent the metal from becoming too thin and to help support the patch we weld on. If the metal feels too weak after you have removed the loose rust you may have to replace the other side as well. The presence of the rust is not the concern; it’s the strength of the underlying metal. Even though this doesn’t look that great, it actually was pretty solid and would be even more so afterward.
MUSTANG RESTORATION: TRUNK LID REPAIR- STEP #4
We cut a metal patch piece and then test fitted it to the opening. You can see we did a pretty decent job when cutting it. Accurately measure the opening and use tin snips to cut a piece of similar metal. Match the gauge/thickness and material specification as closely as possible and leave a relatively small gap between the patch and the area you’re fixing. The patch piece should be as clean as possible and free of any coatings that would interfere with (or be damaged by) welding. Unfortunately, there usually isn’t a good way to protect the back of such patches unless you have access to the backside after they’ve been welded.
MUSTANG RESTORATION: TRUNK LID REPAIR- STEP #5
Cover any noticeable rust with a suitable sealer before welding the patch piece. Use a rust converter to change the rust to an inert substance that can be painted. We didn’t need to do that in this case; the fact that the rust would be sealed from the air (and any water, should some find its way to it) was what we were after. Do not get any sealer on the weld joint, but otherwise apply it liberally to any areas that still have rust or are likely places for rust to form. A small brush usually works best in tight areas such as this.
MUSTANG RESTORATION: TRUNK LID REPAIR- STEP #6
The heat from welding helps dry/cure the rust sealer. However, we preferred to use a heat gun to dry the rust sealer, so it didn’t seep into the joint while we were welding. After applying heat, we removed any residue on the weld line prior to setting the patch piece in place. Welding such thin metal is its own challenge. It’s more complicated when it has been weakened by rust. Make sure you weld all around the patch for maximum strength.
MUSTANG RESTORATION: TRUNK LID REPAIR- STEP #7
You generally want to tack weld the patch piece down in a few places before you do the final welding. This helps prevent shifting or distortion, and deters some heat from being transferred to the adjacent metal. When welding on relatively thin sections such as this, it is usually best to go in short bursts to prevent overheating the area. Use heat sinks and/or special gels that stop heat transfer, if necessary.
MUSTANG RESTORATION: TRUNK LID REPAIR- STEP #8
After welding, the surface should be ground down as smooth as possible to minimize filler use. Ideally, you would be able to grind the area and leave a smooth, bare-metal surface so you don’t see the weld lines. We were not able to fully support the patch piece from behind, so it sunk into the cavity we cut. This resulted in the weld lines being above the surface of the patch to a greater extent than we’d have liked. Not a big problem, but it will need more body filler.
MUSTANG RESTORATION: TRUNK LID REPAIR- STEP #9
Here is another car that shows how complicated this type of small area fabrication can get. The pieces of metal patch had to be very specifically shaped to blend in with the surrounding metal. Some filling needs to be done here, more filling would have been needed if so much extra care was not taken in shaping the patch pieces. In the case of a show car like this one, the decision to make the repair completely smooth or not usually depends on how the area looked from the factory. You wouldn’t want to make it look too smooth; it needs to look authentic rather than perfect.
MUSTANG RESTORATION: TRUNK LID REPAIR- STEP #10
Even though painting your Mustang is covered in Chapter 4, we’ve shown the deck lid being primed to illustrate how the repairs at each end are now invisible. This is also a reminder that the bare metal left after welding should be sealed/covered to prevent air from forming new surface rust. Before priming, take extra care to ensure all fastener holes are properly sealed to minimize the chances for future seepage.
Inner Fender Repair Step by Step
MUSTANG RESTORATION: INNER FENDER REPAIR- STEP #1
This was what was left of the battery tray in our car. It was the only area in the car that had substantial corrosion. Many years ago, before the days of maintenance-free batteries, battery acid had accumulated on the tray. Over time, it ate its way through the metal of the tray and the inner fender panel. This is a lot less likely with modern batteries that do not require filling with water and are essentially sealed units if they are kept upright. Many batteries (gel cells and AGM-types, for example) can actually be mounted in any position, since they have no fluid.
MUSTANG RESTORATION: INNER FENDER REPAIR- STEP #2
This wheel-well side view shows the extensive battery acid damage to the bodywork. If it had deteriorated much more, the battery would be free to move around because nothing would be left to hold it in place. Fortunately, there are replacement panels available for this that greatly simply repairing this area.
MUSTANG RESTORATION: INNER FENDER REPAIR- STEP #3
The replacement we used is a close match to the factory piece. The new piece has the metal that the original part is missing. The first things you notice are the extra holes on the new part. These maximize the interchangeability of the part (a single part fits multiple cars) and also help better duplicate the crash behavior of the part. At least most of the holes are the right shape, even if there are extras. The original also has fewer stretch lines on the flat areas.
MUSTANG RESTORATION: INNER FENDER REPAIR- STEP #4
A comparison of the higher-quality part we used (on the left) with a similar, lower-quality part (right) reveals several differences. The most obvious is that our part was covered in “e-coat” to prevent rust; the other part was bare metal. You can also see the difference in the type of fasteners used for the bolts that hold the battery tray in place. Our part used a simpler method. It also had sharper creases and corners, in general. This indicates the other part was made on dies that are more worn out.
MUSTANG RESTORATION: INNER FENDER REPAIR- STEP #5
Our part had much cleaner flanges than the lower-quality part. Notice how the other part is more wrinkled and distorted; this certainly wouldn’t have helped with installation. We would have had to take extra time to flatten these areas down for welding and to make them fit properly. You can also see the part still has machine oil residue on it. This was used in the die to prevent galling, but means we would have had to clean the part before using it or the welds and/or paint might not hold.
MUSTANG RESTORATION: INNER FENDER REPAIR- STEP #6
This shot also shows how poorly made the other part is. There are several places where the metal has been distorted similar to what you see here, and you can also better see the residue left on the metal and the inconsistencies in the finish. What’s ironic is that this part actually would have ended up costing more than the better part we used.
MUSTANG RESTORATION: INNER FENDER REPAIR- STEP #7
A comparison of the holes shows some pretty significant differences as well. The lower part has more-squared-off holes like the factory part; the holes in the upper part are more rounded. The depressions for the clips that hold the retaining nuts are also creased more sharply in the better piece. Again, the lower-quality part has more-rounded edges, which indicates the manufacturing dies were wearing out.
MUSTANG RESTORATION: INNER FENDER REPAIR- STEP #8
Indentations, such as these, were present in the original factory panel but not in either replacement panel. These are strategically placed to serve a very specific purpose: They cause the fender to crush/crumple in a very specific way in a crash. Basically, they help the car absorb the energy of a crash and better protect the occupants. They also prove authenticity because it’s rare that replacement panel manufacturers incur the cost to include them.
MUSTANG RESTORATION: INNER FENDER REPAIR- STEP #9
Use a cutoff wheel and/or reciprocating saw to cut the original panel. The cuts must be made so enough material remains to securely weld the new part. Usually, leaving about an inch or so from the edge in all areas ensures you don’t take off too much metal. Do not cut the underlying panel or the original welds. The new panel is welded over the adjacent factory panels, just as the original was. Remove the old panel that’s being replaced without damaging these others, if possible.
MUSTANG RESTORATION: INNER FENDER REPAIR- STEP #10
The original panel is removed when it has been cut all the way around its periphery. You will recognize how interdependent the various body panels are when a piece like this is taken out. The radiator support panel is now mostly unsupported along its side and is free to move around with surprisingly little pressure. Be careful not to bend it by mistake.
MUSTANG RESTORATION: INNER FENDER REPAIR- STEP #11
This is another view showing how the cuts were made so they did not go into the underlying panels attached to the removed piece. Only the panel that was being replaced was cut. You can see the shock tower panel edge in front of what’s left of the panel we took out. You can also see we purposely left material behind the frame rail and radiator support.
MUSTANG RESTORATION: INNER FENDER REPAIR- STEP #12
The remaining part of the original panel that overlaps at the top is the place to start grinding out the original spot welds. Remove just enough metal to pry off the remnant of the original panel, as shown. It was important to not damage the panel underneath because we will weld the replacement panel to it. You can use special drill bits that are essentially flat-faced to remove the weld without taking away too much of the lower panel. There are different sizes available to match different spot welds. Use your preferred method, but in any case the goal is to remove only the welds.
MUSTANG RESTORATION: INNER FENDER REPAIR- STEP #13
Spot welds applied along the remainder of the original panel were ground down with an impact chisel, to ease removal of the old panel. Place the point of the chisel directly in line with where the spot weld was and also tilt it at an angle to minimize distortion of the panel that remains in place. It’s very important that the underlying panel does not get torn or otherwise damaged. When the residue of the original panel is being removed, break the spot welds only.
MUSTANG RESTORATION: INNER FENDER REPAIR- STEP #14
Use the same process at the radiator support, but it will take a little extra care because it isn’t as secure and moves around. When working with a panel that no longer is adequately supported, brace it from behind or at least have someone else help you hold it while you grind away the welds and/or use the impact chisel to remove what’s left from the panel to be replaced. Some minor damage is inevitable.
MUSTANG RESTORATION: INNER FENDER REPAIR- STEP #15
With the remains of the panel completely removed, you can grind away any excess residue. Make sure the surfaces you are welding are flat and clean. Also verify that there are no bumps, which will prevent the replacement panel from fitting properly. A sanding disc similar to that shown is likely the best way to go.
MUSTANG RESTORATION: INNER FENDER REPAIR- STEP #16
To restore the shape of the metal on the car for welding, you may need to use a hammer and dolly. The dolly is held behind the metal to be shaped while the hammer blows are applied from the front. Use a flat-faced hammer when trying to smooth a straight surface. There are many different types of hammers and dollies to suit different needs.
MUSTANG RESTORATION: INNER FENDER REPAIR- STEP #17
Drill the holes for the new panel near the original spot welds. You don’t need to be precisely over the old spot welds because you are making new welds with a different technique, so you want to make it look as similar as possible. You also need to grind off any coating in the area around each hole to ensure the best possible weld. Set the replacement panel in place and secure it with a few sheetmetal screws to hold it steady. Make sure everything is properly lined up first.
MUSTANG RESTORATION: INNER FENDER REPAIR- STEP #18
Make a weld at each hole to simulate a spot weld. After all the welds have been laid down, grind each one flush with the panel. Don’t worry about minor pinholes or other visual defects as long as they have no functional effect. As long as the weld penetration was sufficient there should be plenty of strength to hold everything together. While this approach may not perfectly replicate the look of a spot weld, it does a pretty decent job for a lot less cost. The main thing is that the welds are strong.
MUSTANG RESTORATION: INNER FENDER REPAIR- STEP #19
Often replacement panels do not include all of the holes on an original panel. Therefore, you may have to drill holes in the replacement panel to match the original. Again, this is mainly a matter of parts interchangeability. The panel is used for multiple applications and defaults to not having holes where some might be needed for certain vehicles. To prevent rust from occurring at these drilled holes, make sure you seal the bare metal edges.
MUSTANG RESTORATION: INNER FENDER REPAIR- STEP #20
Properly lining up the replacement panel on the frame or mounting brackets is critical. Therefore, make sure the panels are also properly located. We ensured that the radiator support was properly located on the new panel before we welded the two together. If you fail to properly align these components, fenders and other parts can be difficult if not impossible to install later on. This is especially true with parts and panels that locate critical items.
MUSTANG RESTORATION: INNER FENDER REPAIR- STEP #21
After all welds have been made, coat all exposed baremetal surfaces with primer or another suitable sealer to prevent surface rust. Primer helps to highlight the appearance of the welds. You could also grind the weld smooth and use a sandable primer to make them virtually disappear. This would not be authentic looking, of course, but some may prefer a more uniform and smooth appearance for certain projects or situations.
Here is the replacement panel installed solidly in place prior to priming and painting. All of the welds have been ground down and made flush. All screws have been removed and their holes welded, if necessary. We will clean the whole underhood area later so, at this point, we just sealed any areas that required it and then applied a coat of primer.
Small Area Repair: Fabrication
The first category of metal repair is when repairs are to be done in a relatively small area and/or when relatively complex shapes are involved. Often, this is a more severely damaged area of the vehicle where the underlying metal is not solid. This usually requires a significant amount of skill in metalworking and fabrication. Typical instances where this comes into play are the channels around the front or rear window glass, the channel around the trunk opening, the lower edges of the doors, and areas where several panels meet. These are a few of many, many possible examples, yet they tend to have the common characteristic of being places where water collects under normal circumstances. The cowl vent/heater box area and clogged drainage passages can create yet other lists of possibilities.
Wherever this type of damage occurs, it generally involves fabrication of a relatively complicated metal patch to replace the damaged section that must be removed. We were fortunate with our 1968 to not have such problems in the most common areas mentioned, so I show this type of repair being made to the edge of the deck lid. This didn’t require quite as much special fabrication of metal pieces, but the concept is the same regardless of where the work is done. Similarly blending in the patch pieces and sealing, priming, and painting them is also identical in process. The key is to restore the base metal integrity while blending with and retaining the shape of the adjacent metal. After that is done, the whole area can be treated as if it were undamaged and can be finished in normal fashion.
Large Area Repair: Panel Replacement
Often, this category of repair is at a more severely damaged area of the vehicle where the underlying metal is not solid. Over the years, many products have been developed to help resolve
common problems. In body repair, there are many patch panels available for repairing rusted, damaged areas. All of the usual suspects are available: floorpans, trunk floors, quarter panels, doors skins, etc. These make such repairs much easier to complete and they can also help improve the overall result if you stick with quality parts. As I described in Chapter 2, there are different levels of quality out there, and some of the greatest differences are in replacement parts and body panels. Our 1968 only needed one replacement panel: the inner fender panel where the battery mounts. Battery acid had totally destroyed this part so we needed to cut it out and put in a new one.
Experience has shown that it is often best to see if you can get at least a couple patch panels from difference sources and compare them before you decide which one to use. If you do a lot of business with a particular shop, and they carry more than one manufacturer’s products, this can happen. A good shop wants satisfied customers and realizes different customers have different needs and expectations. A customer with a daily driver may be willing to accept a less-expensive part with lower quality and authenticity than would the owner of a show car. We went with a higher-quality item, which more closely matched the original factory part and even cost even less.
The actual process of cutting out the old panel is more involved than it might first appear. We not only need to preserve the structural integrity of the vehicle, but we also want to retain the factory look to the greatest extent possible. This applies most to the appearance of the welds. We did not have access to an electric spot welder at the body shop (they are fairly expensive and not very common) and couldn’t perfectly duplicate the look of the original factory spot welds. Those building show cars that are to be judged may need to find a shop with such equipment, but for the purposes of our weekend-cruiser project or a daily-driver car, the process we used turned out to be more than acceptable.
It basically involved first removing the majority of the original panel by cutting around its periphery with a cutoff wheel and/or a reciprocating saw. The bulk of the panel was removed, leaving only thin strips containing the original spot welds. Then we ground down the spot welds individually and removed what remained of the factory panel with an air chisel. This included the small area left on the radiator support.
After the factory panel has been taken off, the next step is to prepare the area for the new panel. This involves grinding off any unwanted welds, paint, or other things that might interfere with welding. You may also need to flatten the sheetmetal with a hammer and dolly or similar tools to restore the adjacent panels to their correct shape if they became distorted by this work. The new panel also needs to have any paint or other coating material removed from the areas where it will be welded. It must also be checked for flatness and proper shape and corrected if necessary.
Then drill holes around the periphery of the part at roughly the same positions as where the factory spot welds were. You can use the original part as a guide but these do not have to be precisely in the same spot. You should have at least the same number of holes as there were spot welds. These are the spots where you manually weld on the new panel. Of course, if your shop does have a spot welder, you can skip this step and simply spot weld the panel on. In either case, you also need to drill a few small pilot holes for sheetmetal screws, which will be used to hold the panel in place while it is being welded. These should be spaced somewhat evenly around the part and not be in areas that are too obvious even though they will be filled in with weld and ground down after the panel is in place. Then weld the panel in place and grind down the welds to look like spot welds (or leave as is, if spot welded).
After the panel has been welded in place, take care of any other holes that need to be drilled. The replacement panels don’t always have all the required holes, other clearance slots, etc., predrilled, so you may have to do this, as we did on our car. You can also take out the locating screws and fill in the holes with weld before grinding them flat. These may also require some filler or sandable primer to better disguise them if they remain too obvious after grinding.
When you are sure you will not bemaking any more holes or welds you should at least apply a layer of primer over any exposed metal to prevent surface rust from forming. Whether or not you finish the repair in terms of painting depends on where the panel is. If it will be painted body color then it should be painted with the rest of the body. In our case, we simply waited until we painted the underhood area and also applied the undercoating to the wheelhouse side.
Some areas can also benefit from the application of additional sealants or compounds intended to keep moisture from accumulating. Be wary of products that may clog drainage holes or passages and also be sure that any bare metal is covered with at least a sealer. Pay particular attention to
where two panels meet; the mating line can often act as a path for water to wick to other areas. Even when a fastener helps clamp the two panels together, their bare edges should still be sealed somehow. A dab of the Rust Encapsulator or some other form of sealant can go a long way toward preventing rust from starting underneath a fastener joint or deep in some unseen recess behind a panel. The key is to ensure you have a continuous barrier between any bare metal and the air.
Dent and Ding Repair
Although the repair of dents and dings is more similar to repair of minor/surface rust, I saved it for the end of the chapter because it is the proper lead-in to Chapter 4 on paint.
With a dent or ding you have a solid foundation to work with, as was the case with minor/surface rust. The difference is that instead of being concerned about the removal of rust or corrosion, you’re more concerned about being able to restore the area to the correct shape and finish. It’s more a matter of correcting a physical/dimensional problem than it is of correcting a chemical/material problem. The bottom line is that you have to move metal back into a very specific shape. The goal is to get the metal close enough to the final desired shape so that you can then use as little body filler as possible to finish the job before painting. In cases where the damage is too great, that may not be possible, you may end up having to replace the panel if it’s too badly distorted or torn. For the most part, the repair is a matter of access and finesse. You need the correct access to be able to properly manipulate the metal back into shape, and the finesse to get it as close as possible to the final form.
It really helps if you have access to both sides of a panel that needs to be repaired. You can apply pressure with various tools to push the panel back to the desired shape. Tools such as special hammers, dollies, spoons, etc., can help return the metal to the shape you want. There is a degree of skill involved, however, to cold work the metal back into shape. It’s not just a matter of banging on it until it looks better. Good body people can get a better result in less time with less effort due to their knowledge of specific techniques to make the metal behave the way they want. If you are not aware of these techniques, read up on them or get some advice from someone who’s done the type of repair work you want to try.
Bodywork is one of the areas where it usually pays to have a pro do the job if you haven’t tried to do it before. It usually ends up saving time and expense. This is especially true if you don’t have access to both sides of the damaged area; you would likely have to use a stud welder and puller or a similar type of equipment to pull the metal from the front rather than being able to push it from behind. This takes even more skill and special equipment because the studs must be applied very carefully to hold the metal and they must also be carefully pulled using a slide hammer. After the pulling has been completed, the studs must be ground off and the area where they were attached must be smoothed. It’s an extra, but necessary, step.
Repairing dents and dings is mainly a matter of carefully manipulating the damaged metal back to the desired shape so that it can then be filled and sanded as little as possible prior to being primed and otherwise prepped for painting. Here, less truly is more in terms of getting the desired shape with minimal effort and use of body filler and or other buildup. (Proper application of body filler and other steps involved in preparation for painting are shown in Chapter 4.)
Written by Frank Bohanan and Republished with Permission of CarTech Inc