912 Registry :: Replacement Floor Pans

From: Jim Loomis;   My '68 912 was the victim of both demon salt corrosion and numerous inept repair attempts before I purchased the car in '92. I drove the car for two summers after rebuilding the engine, but I hit one pothole too many, and the front suspension collapsed at the front crossmember attachment points. My financial and emotional attachment to the car was too great at that point to let it go, so I looked into having it repaired at a local body shop. They quoted me a minimum of $6,000 for the repair. This was way beyond my budget, so I took a night class in welding at the local High School. The instructor advised me that MIG welding was the way to go.
After shopping around I purchased a Lincoln Electric Weld-Pak 100 MIG welder with the MIG gas option at Home Depot.   I liked this setup more than some of the other cheaper MIG outfits that were currently on the market. Some of them don't use the gas, they only use the flux core wire. These work fine on thicker metal, but they blow holes right through the thinner sheetmetal of a car body. I use an Argon/CO2 mix, and I have had great success with this setup. It is very important to have the metal as
clean as possible, and the joints have to be tight. I use vise-grips to clamp the two pieces together while tack-welding.     In many cases it is not possible to use vice-grips, so I use #8 sheet metal screws to hold parts together at the flanges where they overlap. After I tack the part, I remove the #8 sheet metal screw and then fill in the hole with weld. This technique works very well, especially where the floor pan is welded to the flange on the inner longitudinals. This joint was originally spot-welded
at the factory. To duplicate this effect I drilled 1/4" holes in the flange before fitting the pan. Then I filled in these holes with weld. I found that it was difficult to achieve proper penetration using this
technique at first, so I kept turning the current up until I found a setting that seemed to work well. Even so, in some areas I resorted to a continuous bead weld, because I felt that it would be stronger and afford me better protection from incoming moisture.
I bought the pan in three sections, front, rear and middle. The front pan came from Porsche, and goes from the pedal cluster area to the front trunk wall. The middle and rear pans came from Restoration Design. Since this was such an extensive repair, I decided to dis-assemble the entire car to make access to all of the repair sites easier. I removed the engine and transmission, gas tank, gutted the interior, removed the front and rear suspension, and basically stripped the car down to a bare shell.
This became a case of "well, as long as I've gone this far, I might as well...". So, I removed the bearings and hubs from the rear suspension arms, bead blasted the arms, painted them, and reassembled the bearings after cleaning and repacking them. I also bead blasted the front suspension
components and painted them. Someone along the way had replaced the right front shock with one from some other car, and it was so stiff that it would hardly compress. The left side shock was stock and very loose, so this explained why the car had some very unusual handling characteristics!
Whenever I took a left hand turn, the car would hardly lean at all. On right turns, however, the back end would break loose with hardly any provocation. I replaced the struts with Koni adjustable cartridge type units. The car is still not done, but I hope that they work ok(I am sure that they will be better than what I had before!).
I installed the three floor panels one at a time, cutting out only enough of the old floor to allow replacement with the new piece. I did it in stages because I wanted the remaining sections of the old floor in place to help maintain body rigidity.
Someone along the way had replaced the rocker panels, but they didn't install new inner rockers. Whenever the car was jacked the rocker would give way at the jack support. I cut out the rockers, and to gain access to the rear rocker reinforcements I cut out the door jambs and the front portions of the quarter panels.
Replacement quarter panels are very expensive, so I used a jig saw and carefully cut the quarter horizontally about 6 inches up from the torsion bar hole. I made a cut that runs parallel to the floor from the wheel well to about where the door latch is located. After the rest of the work was done I butt-welded it back in place, using hundreds of small tack-welds spaced far apart to prevent warping. Eventually there are enough welds overlapping that the entire gap is filled in. Then some careful grinding cleans it up almost as good as new. It only took a fine skimming of filler to make the repair invisible. ( I learned this technique from watching The Collector Car Restoration Home Video Library
VOL.3 "Patchwork and Metal Finishing", available through Eastwood) The front floor pan didn't have the hardware for the pedal cluster mounting, so I drilled out the spot welds attaching the old one to the old
floor panel and reused it. Also, the threaded inserts for the rear supports of the front crossmember weren't included, so I reused them as well. None of the holes were cut (for brake master cylinder, wiring, etc.) so I had to carefully locate and cut them out too.
Makita makes a 4" angle grinder that proved invaluable during the whole process. It's small enough to get into small spaces, and with a wire brush attachment works well to clean up areas before welding.
I ended up replacing the pan, front gas tank support, inner and outer rockers, jack support/ receiver and reinforcement, and rear rocker supports. I also had to fabricate many other small pieces to fill in gaps
where there was nothing left to attach metal to.
So, how long did it take me and was it worth it? It is now Aug.2000, and I am just finishing up the final body work in preparation for painting. I started the work in Mar. 1995, and I finished the rust repair
portion June of 1999. Here in Syracuse NY the winters get very cold, and I don't have a heated garage, so there are about six months of the year that I don't get to work on my project. Whoever said that it's like building a boat in your basement is just about right. I'm happy with the results of my work so far, but I'll be happier ( and my wife will be too!) when the car is finished and I'm on the road driving it.
Anyone with questions or comments please feel free to email.

From: Bruce A Streeter; ; 912 Replacement Pan: I have replaced the pan area using a local shop and parts from Restoration Design. The initial fit was not perfect, but with a bit of trimming it seems to have worked out fine. regards

From: Christophe; ; Hello Rick, My 69 912 needed a full replacement of the floor pans and of the front body parts. The front body had already been repaired with non original parts and it was very bad.
The 2 battery trays did not need replacement. For the floor, I bought 2 pans which are made by Dansk autopart (I bought these parts in Germany), it cost about $400 each. For the front body, I bought parts to my Porsche dealer.
If I can give only 1 advice for the replacement of the body on the front is to take care of the hight of the front end part so that your lugage compartment makes no problem to close. I got a little problem to solve for that.
For the replacement of the floor panels, you can check that seats are well positionned, that the master cylinder will work properly with the brake pedal and that the gas pedal will also work properly.
This job was done by a friend who has already repaired several porsches.
Good luck to all 912 body workers,
Cheers,
Christophe

From: Dave Hillman; ; Interesting question that I'm working on right now. I knew that my car had problems with rust in the front body pan when purchased in May 2000. I had planned to get it fixed this winter when the weather gets bad, but have elected to move the date forward. I'm concerned about safety since the pan holds the front of the suspension. If it were to collapse, it would be a lot worse that the repair. I've been told that bad cases have occurred under hard braking or cornering. I've purchased the parts and toyed with fixing it myself, but it seems too much like building a boat in the basement. It could take forever. See it all including pictures at
http://www.hillmanimages.com/912/
The repair cost will be about $2K. Welcome to silicon valley. Regards, Dave

From: RevGuy912; ; On my "rust-free" California 68, we hadn't realized how bad the pans were until we ripped out the interior and my dad and I literally fell through the dozen or so holes in the floor. The rear seats were also rotted through. So we took the car to Speedwell Engineering in San Fernando, who does the race preparation of mine and my dad's vintage racing Austin Healey Sprites. They are great with rust repair, and they were going to install a roll bar in the 912 anyway. The pans came from Best Deal, but (luckily) the car did not need a battery tray. We figured out later that the rear window gasket was junk, which let the water down into the car. The guys at Speedwell also filled the rear seats with fiberglass, which was cheaper than welding in a steel piece. It doesn't really make a bit of difference if it is steel or fiberglass. After all of that was squared away, Speedwell installed a very nice custom roll bar.
Happy motoring, Efrain Olivares, Jr.

From: Gregg Dunphy; ; When I bought my 912E in September of 1991, the front pan, gas tank support and battery tray areas were already in pretty bad shape. I had them replaced in September of 1995. Going on the reccomendations of other satisfied Porsche owners, I had the restoration and repair work performed by Magic Customs of Lynnwood, WA. It cost me $2,253.46 as the damage was quite extensive, requiring much more work that the usual front pan repair so typical on 911s and 912s. The shop documented the
damage and repairs and then did a fabulous job of repairing the damage, right down to the re-applying the factory undercoating and duplicating the double coating of the two different colors of paint originally
applied to my car by Porsche at the factory. The repairs were done so skillfully as to be virtually indiscernable. I installed a red Optima battery as soon as I got my 912E back from the shop. After five years, I have seen absolutely no reappearance of rust or other corrosion in any of the restored or repaired areas. May all of your front pan rust experiences end as happily as (but much cheaper than) this one did for me. Gregg Dunphy

From: Keith&Jackie; ; My son asked me to send some information about the battery pan replacement I had done on his '68 912.
I took it to Kahlers in Dublin, Ca. They repair porsches and BMW's. They removed the gas tank, and the driver side front suspension, then cut away a large portion of the pan, not just the battery section, so as to be completely away from any possible corrosion. The new pan section fits in and is welded in place, then the front suspension and gas tank are put back in.
It cost approximately $1500 and took five days. I'm not sure the exact cost as I hd other work done, and couldn't find my receipt.
If you are interested, I will try to find out from Kahlers the company that supplied the pan section for them. They said they do this type of repair regularly on older 912's and 911's
Keith

From: Johnflacey; ; My ' 69 Targa had no slight pan rust, but beginnings of flaking, when I had the old undercoating sandblasted, and recoated it with that rubberized bulletproof epoxy stuff. The only way to get it off your hands is wait two months. Still perfect five years later. With my ' 66 Coupe @25 years ago, I bought it with a pan that was going rapidly -- cost me >30% of the price of the car to have it repaired. That was when the original cars were first beginning to deteriorate, and OEM with attendant prices was the only option, plus maybe certain early lack of familiarity in the repair community. Best regards, John L.

From: Alexander v. Wachter; ; Performance products California (I dont know if they are still in business) offered a complete replacement pan with the whole spare tire section and, lets say, a front area (40% part of this) replacement pan. The part cost was around 100 dollars and the welding job cost me 400 dollars inclusive the new protection coating. The job was done in Sarasota, Florida.
Alexander (912register Germany)

From: Chris Smith; smith244@llnl.gov; Hi Rick, I haven't had to replace the pan but I replaced the battery tray area. I used naval jelly to get all of the rust off which took several applications. After getting everything clean I got a generic poly coated metal battery tray and mounted it with four screws instead of the usual two. At that point I installed a red Optima battery which is the best investment($120 in Northern California)I could have made for the most troubled area of my car. It was well over a year ago that I did this work and the battery area and corners still look new. Chris Smith, '76 912E

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