NineMeister

Any aircooled regulars will no doubt have come across my RL postings on the 964 & 993 forums but surprisingly this is probably my first thread about a serious bodywork project we are doing on a 996GT3.

In the UK there is no doubt that our classic weather and the use of salt on roads leads all cars to potential floorpan corrosion issues and when it comes to the GT3 (and especially RS) we noticed from the early days that there was precious little protection to the floor areas on some cars. Well, possibly sooner than we expected, we now have a Mk1 GT3 in the shop that is having a complete floor pan restoration as a result of the lack of paint protection from the factory finish.

Initially we looked at the car when it came in and thought it would be a relatively quick job to strip off the running gear, steam clean the floor, scuff the e-coat and repaint it back to factory fresh finish. How wrong were we? As it turns out the only protection the floor had was from the grey e-coat and on close inspection there was clear evidence that water was penetrating below the finish and corroding the parent metal. Stripping off the e-coat, cleaning the floor to bare metal and applying a full etch/prime/seal/gloss was the only solution we could envisage.

With the running gear off & the shell loaded on the spit, this is what we discovered:

NineMeister

At this stage the rust has eaten away the metal under the e-coat but fortunately not managed to go much further, so stage one was to use a rotary wire brush to clean up the accesible areas.

NineMeister

The first thing we noticed were all the corroded body studs. Out came the carpets, in came the welder and on went a new set of studs....

NineMeister

The next problem was how to deal with the inaccesible areas of the tub. Dipping & re-E-coating the shell would have been the perfect solution but it was not considered an option because of price for the whole job, so the next plan was to grit blast the areas that we could not wire brush. However, the trouble with this plan is that all the blasters we knew uses too coarse a medium which damages the metal panels, so we came up with a plan to do it all in-house. It's not ideal, but with care we managed a satisfactory solution.

With suitable protective gear, a partial tent around the shell and a Heath-Robinson portable grit supply unit for the hand blaster, Owen set about the task. It was slow, but at least we knew that the metal would be in perfect condition after the job.

NineMeister

If you look carefully in the photos you can see how we used bottle corks to plug up all the round chassis holes. No lads, we're not members of alcoholics anonymous, we bought the stoppers off Ebay.

AllanJ

Wow! This is a huge job.

I don't drive my car in the winter, but I'll carefully inspect the underside after seeing this.

Thank you very much for posting.

Cheers,

SH || NC

I love these threads!

911SLOW

Colin, It was about time you started playing with GT3s..

P.J.S.

Including stripping and replacing parts and the actual body work -- how many hours did this take?

Thank you for posting -- very interesting

NineMeister

Erm, I'll let you know how long it took when we've finished...


Glad your interested in what could be going on underneath your car, rest assured that I'll post some more & varied threads on 9m GT3 work in the near future.

NineMeister

One other little job we did was to repair the seam at the back edge of the boot floor. The car must have gone forwards over something which peeled back the overlapping seam, a quick dress with a planishing hammer and the odd tack or two easily put it right. The welds will be covered in seam sealer when finished for the correct factory look, although now of course we need to blow in the colour inside the boot where the weld has burnt through (likewise on the inside of the floor where the new studs have been fitted).

FFaust

Now, that"s something we don't see too often. Thanks for posting.

NineMeister

OK, so the floorpan was divided into workable sections which have now all been blasted & zip-wheeled (rotary brushed) as required before the fresh, clean metal was lightly etch primed. We had to work in sections in a paint-as-we-go method due to the moist November atmosphere & overnight condensation tarnishing the new surface.

Now it is done we are waiting on the booth being cleared before we can begin the big repaint which will be done at one go. The process list is:
1. Clean
2. Rub down & scuff
3. Etch
4. Seam sealer, fine
5. Prime
6. Brush / spray seam sealer
7. Prime
8. Solid colour grey to match original e-coat
9. Dust colour yellow to original "overspray" look
The result will be a fully painted & sealed floor that looks like the original but is fully gloss painted and protected for the future.

Charlie Boy

Hi Colin, for those of us using our cars year round in the UK what do you recommend to prevent corrosion like this? Would Waxoil or Dinitrol be the way? My car looks fine with only a few very minor spots of rust where the spot welds are, but of course I would like to protect it from the road salt in the future!

C

NineMeister

Good question.

The minimum annual requirement that we recommend is to fully steam clean the whole underside of the car, dry it off, then spray everything with clear waxoyl. That said, once the corrosion starts to get under the E-coat the game is all over, so the only solution then is to do what we are doing to this one.