Frequently Asked Questions

Q: Bare Metal Panel Preparation

I just bought some brand new metal panels for my car. Do I need to do anything to prepare the pans for priming? What type of primer and paint should I use? What do I do about the paint that burns/peels off when I weld?

A: Clean the bare metal with lacquer thinner (the type you would use to clean a paint gun). This will remove all of the machine oil coating. Then, use a self etching primer. If you want to install them before painting you can. It’s just been easier for me to hit them with paint and then later retouch them as needed.

I usually do all my cutting and trimming before priming, then tape off the area I plan to weld and prime and paint. After installation, clean the area with a light sand paper, then thinner, self etching primer (I like the aerosol cans), and paint. If your painting the whole car, It may be easier to wait on the paint.

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Q: Fender Alignments

I can not get my fenders to align properly. Anyone have any tricks?

A: Two tricks that you need to do a fender alignment properly.

1. With fenders off the front end will sag, as fenders are a major part of front end structural support. Support the subframe and body so that there is no sag in the subframe and firewall before bolting the fenders back on. Also make sure the frame is aligned with the body via a 5/8 in rod thru the alignment hole in the front frame to body mount.

2. The fender fits best at top if it is stretched a little more than the shape it has when off the vehicle. Get your gap right at the top and put spacers in the bottom to spread until the center crease lines up with door. Be sure and do this with no load on the subframe and body.

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Q: Floor Pan Replacement

I am about ready to replace the floor pans in my Firebird. Anything special I need to do or suggestions for completing this task.

A: I’m no expert, but I did replace the floor pans on my 1968 firebird. Some of the things I learned are:

• Do one side at a time to keep the body straight. If you have a convertible, weld in some temporary supports from the dash to the rear seat. (Angle iron or square tubing)

• Cut around the forward body mount brace and use that to locate that corner of the floor.

• Cut around the extra bracing for the leaf spring front mount, and use that to locate the back of the floor.

• The seat support has about a million spot welds, and you have to take that off to get to some of the spot welds for the body mount which is under it.

• Measure the distance from the old floor to the top of the door sill or to the bottom of the rocker panel before cutting out the floor and use that dimension to locate the outboard side of the new one.

• There are a couple of factory holes in the transmission hump which can be used as reference points to locate that edge. I left 3-4″ overlap so I could move the floor pan around, and to maintain the strength of the transmission hump without the old floor.

• Set the new floor on top of the old one and mark the edge with a soapstone, then cut 3-4″ below the line, going around the aforementioned items.

• It is easy for the floor to twist and get away from being level, so check that often while welding.

• Plus the basics: tack weld in various areas, and move around a lot, so as not to warp the floor. Seal the seams when you are done with seam sealer, available from various suppliers.

Again, I am no expert, and you may get better advice on this board to be 100% factory correct.

A: I’m not an expert but I’ve done a couple of 1969 floor pans… One coupe and one convertible. First thing you need to no is that the convertible will be much more difficult than the coupe. When I did mine, I left the belly brace ( the brace that is underneath the car) in place. You may also want to support the car in to keep it from buckling in the middle. A brace at the top of the door between the door jam on each side is best. Do one side at a time to keep as much support a possible. After this I used these procedures:

• TAKE NOTE OF THE LOCATION OF THE GAS AND BRAKE LINES IF THIS ISN’T A FRAME OFF RESTORATION.

• prime and paint new pan.

• removed the seat pedestal.

• removed the rear seat floor brace (the angle piece connecting the tunnel to the rear jam).

• remove bottom of old floor pan and clean up belly brace (take note of the different support pieces that are welded to the original pan. remove as much old metal as the pan will cover but leave these supports in place).

• set new pan in place and scribe a line around the top of the pan onto the old sheet metal (make sure it sits tight on belly brace, use screws if necessary).

• trim excess metal approx one inch below line.

• re-install new pan and re-check scribe line. (make adjustments as needed).

• while pan is in place, mark seat belt location, rear sub-frame attachment point and the different brace locations from underneath the car.

• once your satisfied w/ fit, trim to 1/2″ of scribe line

• cut holes for seat belt and frame attach point.

• I drill holes in the pan to allow me to spot weld through the pan to the different brackets located on the bottom of the car.

• install pan and weld (tack weld all the way around about 4″ apart then tack in between first welds until welds are 1 to 2 inches apart then weld solid).

• re-install rear brace.

• reinstall seat pedestal.

• repeat for other side.

• Be sure to caulk area between the new pan and the inner rocker panel.

• TAKE YOUR TIME.

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Q: Floor Pan Replacement

I’ve got some rusted floor pans front and rear, both sides. Going to pick up some replacements. I’m no welder, so I was just going to have a local welding shop do the job.

Any advice or do’s and don’ts? Brake lines, cables, fuel lines? Welding scars or sealant?

A: When it comes to floor pans, there are a couple different types. Most pans are designed to be dropped in and welded from the top. The rocker panel side is turned up. These are the simplest to install. All you do is use a air chisel to cut along the edge of the pan, flatten out what’s left and drop in the new pan. You can make a scribed line all the way around the pan then pull it back out and trim to 1/2″ to 3/8″ to the edge, less if your brave. Then simply just use sheet metal screw to hold everything in place and weld it up. I weld them as solid as possible and then use 3M seam sealer.

The other type has the rocker panel edge rolled down like the original. These aren’t really any harder to install (except for maybe on a convertible) but do require some welding from underneath. The removal of the old pan is the essentially the same. The biggest difference is spot welding the replacement along the original pinch weld seam. From the bottom, they look more like the originals. That is IF care is taken to hide the other seams. I try to help this out by making the repair seam that runs along the tunnel as high as possible. Don’t forget to leave holes for the seat belts.

Removal of the seat pedestal is the same for both replacement pans. I prefer to cut the whole pedestal out then try to remove as much of the old pan as possible. I suppose they could just be trimmed and cleaned and welded in place with the old pan on the bottom but be sure the original pan imprint is a very close match. Otherwise your seat may not sit level or square. Be sure to locate the hole for the subframe bolt.

As far a repair projects go, this is probably a easy as they come. even if you don’t do it perfectly, almost no one will ever really see it. If done with care, it’s even hard to tell when the car is up on a lift. You may want to search the archives. I’ve been through this process before and I believe Geoff posted some of the instructions.

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Q: Floor Pan Replacement (revisited)

I have just found that I need to replace the passenger side front floor in my 68 and wondered if anyone had any experience with this procedure. It looks as though I must remove the seat attachment structure then go at the floor after that is removed. My question is what type of tool is best suited to break the spot welds and other weldments? Cold chisel? Small explosive charge? Any words of wisdom would be greatly appreciated…Oh, also I have a weld pak 100 flux core welder would that work for the welding?

A: I know there will be others responding to this question…. and I believe there is more than one way to perform this task. First off, if it is a convert, then you have more chances of twisting things out of place. I’m about 75% done with doing total floor pan reconstruction on both sides on my convert. I have taken an excessive and some would say obsessive amount of time in doing mine, but then I’m trying to make mine look close to factory both inside and out. My only advice to you is to support the vehicle carefully and with equal pressure on both sides. Consider welding in temporary braces if you have any doubts. I did not, but mine is just a shell and I have very carefully supported the shell in critical points. That may not be proper for your situation.

Go slowly, AND PLEASE… CAREFULLY, mark the alignment of the seat support and frame brace before you remove them. Measuring afterwards is very difficult. Cut carefully and plan on it taking longer than you thought. As far as cutting goes, use a good spot weld cutter on the seat support brace and frame brace (underneath the seat support brace). Use an air chisel on parts of the old floor pan that you want to rip to shreds and be careful not to damage anything else with the air chisel. Once the floor is out, clean everything up carefully and get all of the rust off of the braces and rockers before repainting and re-welding. ONE BIG CONSIDERATION…..

Examine the front floor board supports carefully. Mine were really bad due to rust. I had to remove them, reconstruct them with heavy gauge steel and reweld them in. It was really time consuming, but I won’t have to worry about doing it again.

A: You’ve already received a lot of good advice so I won’t put you through a lot of details, just some details.

If your planning on removing the seat pedestal, keep in mind the damage your going to do the existing floor pan. The spot welds run across the front, sides and back and as mentioned, there are also a couple you can only get to from the bottom unless you disassemble the pedestal (which I don’t recommend). Even if you only need – of the floor pan, consider buying the whole unit. This will give you enough metal to repair any damage cause by the seat pedestal removal.

When you purchase your replacement pan, be aware that most replacement pans have the lip on the rocker panel side folded “up” te make welding easier. If you are doing a partial pan and you have to repair the rocker area, you’ll want a pan that folds “down” to match the original. I’ve only seen these sold by a company called C.A.R.S. Inc. (714-525-1956 California or 248-398-7100 Michigan: www.carsinc.com)

I just finished replacing my third set of floors. The easiest way I’ve found to remove them is to drill the spot welds along of the top rocker panel then just cut the pan across the front, back, and tunnel. This will allow you to easily remove the pedestal from the car. Then just separate the old floor pan rom the pedestal. The replacement pan is designed to cover the area above the pedestal so repair is easy. The replacement bent to match the original bends so really, the pedestal can only go back to it’s original location. Plus, the spot welds on the rocker side will act as and additional locator point.

Mock fit the panel in it’s final location and set the pedestal in place BEFORE welding. Use self taping sheet metal screws to hold it secure while fitting but pre-drill the outer layer (usually the replacement panel) first.

Q2: I found your advise about removing the pedestal with the pan to be sound. Although I have not removed the floor yet I am planning on doing it as you described. If I might pose a few questions: along the front, back, tunnel side, and rocker to what elevation or point do I cut? Along the front I see the over lap, do I cut such that the overlap is removed? Rocker side: I have the turned down replacement pan I purchased at Classic Ind., seems to be perfect match, Do I drill out the spot welds along the flange underneath the car where the two meet? Looks like that might be the spot. Finally, along the back of the pedestal how far behind it can I cut? Directly at the termination of the pedestal rear sheet metal?

I really appreciate this site and all who contribute! I could reinvent the wheel or I could just ask you all to help. And you do very much thanks again

A: The cut along the front depends on two things, the length of your replacement pan and the amount of cancer. If you have a full length pan that extends up the kick board then you can remove all the metal up to the top of the pan.

As far as the seam, a full length pan will cover this area. The full pan only mimics what was originally two pieces. The thing to look for in this area is the lower firewall extends under the toe kick. I usually cut around this piece and lay the new pan over the top of it. This way you can’t get the pan too low. You may have to trib. your pan on the rocker side or open the pinch weld at this point because the pan is originally sandwiched between the lower firewall and the rocker.

I would not try to remove the spot welds along the bottom of the rocker. Instead, I would use a air chisel on the bottom side along the 90 degree bend. I usually start at the front and rip the old floor front to back. When the old floor is removed, hammer the edge of the old floor flat against the edge of the inner rocker. When you go to install the new pan, pre-drill the lip of the pan to mimic the spot welds along the bottom edge where it will attach to the inner rocker panel and weld.

As far as how far to cut behind the seat pedestal, again it depends on how much new metal you’ve purchased. If it is just a partial pan, find a couple of common points to measure. If your new pan has a pre-drilled hole where the rear sub-frame bolts enters, use this point and compare it to the original. If this hole is not there, look at the tunnel side and note the slight bend. This should also be evident on the new pan and is also a good reference point.

As far as the elevation of your cuts, once you remove your seat pedestal, lay the new pan in place and trace a line around the whole thing then, DON’T CUT ABOVE THIS LINE.

Hope all this helps. Let us know if you have more questions,

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Q: Floor Pan Replacement on Convertible

I got me floor pans for the conv.. Here we go … Get ready for the questions. Going to pull the seats and carpet out this weekend to take a peek.

1. Does that Scott Jason camaro restoration book have any good info on this subject?

2. I have a Fisher Body book for 1968 I find it screchty on the Fbody data covers all body styles is there a manual in print just on the F body,

3. Anyone ever done this with out taking the subframe out of the car?

4. Seat perches have to come out?

5. How about that cross member on the tunnel for convertibles. I ain’t seen a car yet with that installed. Does it bolt to the floor pans? No threaded wholes in the new pans.

6. Body bushings bolt to the floor pans … right. No holes. Logic tells me that fabricaing and welding the pan in takes some BFH and that you measure and align after all is welded in place. How? Measurements?

The pans are one piece left and right from Classic Idustries. I beleive the sticker says the company that made them are American Design. Anyone had any expreince with these? Should I stop right now and send them back? Fit like _hit. Knowledge is everything. I am not a body man. I plan on doing everything but cutting them out and putting them in. I will find a body guy to do this. I need to arm my self so I can ask the right questions and tell if the job is going to be done right. This is not a concours restoration I’m looking to get it done quickly and cheaply.

A: Just a couple of things that may help…

Floor pans can be replaces without removing the sub-frame. I’ve done it on both a convertible and coupe without any problems. I also highly recommend additional bracing for the convertible. Also, take measurements of the door gap BEFORE you rip out anything. Check these measurements BEFORE you weld anything.

Coupes are pretty easy and straight forward. Refer to the FAQ for a previous write-up.

Convertibles are a little more difficult because of the belly brace but once you remove the seat pedestal and the old pan, it will help you align the new pan. Remember the additional brace that is just in front of the rear seat hooks.

On both installations, I used the “turned up” style of replacement. This makes welding easy as it’s all done from the top. I used tube style body caulk to fill the cap at the bottom. Once painted it looks OK. While my car was up on the rack getting a new exhaust, I received a lot of good comments on the pans from a guy who runs a local restoration shop.

There are pans available that turn down to mimic to old pans. I found some from a vendor at a swap meet. I don’t have his card but I think a company called C.A.R.S. (www.carsinc.com) carries them. These will allow you to make the pinch-weld below the rocker panel like the factory.

I pre-drilled all my welding hole and the rear frame rail mounting hole before I welded the pan. First I trim and install the pan with sheet metal screws until I’m satisfied with the fit. I temporally re-mount the seat pedestal also using sheet-metal screws. Once satisfied, I use a pencil to trace around the bottom brace and through the seat pedestal. This gives you an idea where to drill the spot-weld holes and where to drill the hole for the body to frame-rail bolt.

After I’ve drilled all my holes, I remount the pan, seat pedestal, and frame-rail bushing and bolt, check my measurements and weld. If your door opening seems to have sagged a bit, try to position some jack stands under the rocker panel closer to the front of the car to allow more weight on the rear. Do this slowly with a floor jack under the rear-end.

A: 4. Seat perches have to come out?

If I recall correctly,which I do,them there “perches” are spot welded in,and as such can be hacked out. Thats what I did,I never even considered going the route of removing the sub frame, though if you do,that would be a good time to get some new body bushings.

A: I have just finished putting floors in a 1968 Convertible. You can’t see all the areas that may be rusted from the inside. Get and Ice pick or something sharp to poke with.

3. since the subframe bolts to the seat perches I don’t see a way to get them out with out removing the subframe.
4. If you are going to replace the whole pan and I would suggest that, then yes they will have to come out. There is also a reinforcement plate at the rear of the floor that will have to come out too. Under this is one place I found a lot of rust that I couldn’t see before I removed it. There was also a lot under the seat perches. The Hooks for the rear seat will also pose a problem. I cut the old floor and new floor around them and left them attached. My floors were fine in that area.
5. The Convertible Plate bolts to the frame not the floor pan.
6. I cut the holes in the pans for the subframe after I had the seat perches welded in. I drilled and small hole from the inside through the mounting nuts fastened to the seat perches to mark the center of the holes and then used a cut off toll to make them large enough.

One other area that was a problem was that the new floor turns up or in on the out side of the floors and the originals turned down or out. I did different things with each side of mine and wasn’t happy with either so I will leave that up to you.

A: 1. Nope, Jason Scott says nothing, however the list archives contain very good explanations of what to do.

4. Definitely remove seat perches and rear reinforement plate, these covered a lot of hidden rust on my car. These can generally be repaired and reused.

5. The conv. reinforement plate bolts to the belly-brace, not the floor. It is much easier if you can remove the floor and leave all underfloor bracing in place. This assumes that your floor is rusting from the inside out and the underfloor bracing is good.

I used the Classic pans and even though I haven’t welded yet, trial fit is fine. Seems that SFH will suffice.

Again read the archives for the old posts.

A: On the Passenger side I cut the old pan at the edge of the Rocker. This tended to leave a gap where the new floor meets the Rocker from the bottom. It has the potential to get and hold water. I plan to seal it with seam sealer. On the drivers side I cut the old floor about 1/2 to 3/4 of an inch from the rocker and set the new floor on it and welded it to it. This creates a better seam from the bottom but creates a possible problem in areas where it was hard or impossible to weld. The cross member and the support on the bottom Front of the floor.

Another thing I did was to do one floor pan at a time. This was a suggestion I read earlier on this list. This was because the floor is such a big part of the support for the car.

I have mine turned on its side to make it easier to work on.

A: I’ll answer what I can:

3. My subframe was out
4. Take out the seat perches
5. Convertible reinforcement plate bolts to the extra bracing that only the convertible has (under the floor boards)
6. I measured and then drilled the holes after installation. The subframe “nut” is loose and can move around a little. The hole has clearance so the bolt and nut can be move for alignment.

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Q: Interchangeability of the Body Panels

Are the front fenders from camaro are interchangeable with firebird?? any other major componentes??? what work needs to be done to adapt a hardtop quarter panel to a convertable..

A: Front fenders for 67/68 Firebirds/Camaros are interchangeable but the turn signal cut-outs are different. You’ll need to do some mild welding to make your turn signals work.

Quarters are not interchangeable due mostly to the chevrons on the Firebird quarters. Fenders for 69s are not interchangeable.

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Q: Quarter Panel Fit for Quarter and Full

Have heard a few things about partial rear 1/4s vs full gm 1/4s (camaro only?). I haven’t heard very good things about partial 1/4s-alignment plus problems with Firebird louvers behind doors.

A: The aftermarket rear quarters will work with a fair amount of body work. I understand that convertibles represent more of a challange to get them to work. In somecases, rust free used quarters from the Southwest are a good alternative.

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