Blow by blow account of front pan replacement.....

[Airhead]

Okay..........finally got the car into my garage and panels arrived from Berlyn services (good price and prompt service!). Taking it easy as this is the first repair of this kind I've done and also been ill of late but here's how I got on last Sunday:

1. The Victim..........muhahaha 1969 californian import 912



2. The problem.......underside of front pan seriously erm lacking in substance! Looks like this was due to the box section formed by the tank support filling with water and nowhere to drain



3. The plan........in the absence of a chassis jig I used good ole dexion and err 2 meat hooks (i.e. whatever I could find in the garage!) tack welded to the control arms to keep them in place as a reference for the new pan, in addition to measuring everything lots of times. The only concern with this is the effect of the heat on the control arms though at some point in the restoration I will replace these and keep the old ones to make a jig perhaps.



4. Start cutting........drill out spot welds like so and remove tank support:




5. Full extent of the damage can be seen from above Looks like the front pan wont be coming out in such a neat whole peice as the tank support did!



to be continued...........(when I stop coughing and sneezing! )

[Airhead]

Nearly 40 viewers and no replies? No one care to comment on whether this is a good plan or not? Next installment to follow after the weekend hopefully if anyone wants to follow it.

[Nick Moss]

No one care to comment on whether this is a good plan or not?

Sounds like a one way street that you have to continue to its conclusion

I did this work last year on a 70 911E

[Bob_Salmon]

Not the sort of item which is going to attract much response but one which people will refer to over the years.

Feel good that you are doing it and feel better that you are leaving a record for others.

Bob

[Bootsy]

Great thread which members will really benefit from - a future How to in the DDK Fanzine perhaps?

[Airhead]

Well a one way street it certainly is. There's no going back now. I just wanted to see also if any others had experience of doing the same job under my circumstances. Not being able to afford a full on resto just yet I want to get it MOTd and have some fun with it in the mean time as the rest of the car is nice and solid. Nick's jig for spinning the shell looks very neat and I'm sure turning it upside down helps make measuring everything alot easier but I'm not going to strip mine that much so fixing the suspension in place and using it as a jig seemed like the sensible option. Dropping the pan in from above instead of underneath though isn't without its complications which I'll illustrate in the next set of pics and how I got around it..........Perhaps an unorthadox method but hopefully of use to the home restorer

[Gary71]

I think everyone was just too scared to comment, the sight of major corrosion has a profound effect on us early 911 owners....

We tend to go a bit quiet when we realise that this could be our car by the next MOT....

Good luck. Major challenge, but looking good so far.

[Nige]

All I can do is post some images of mine which is a 1976 model (galvanized) that had corrosion around the battery tray, fortunately it only affected the top side of the pan, so only the top section was replaced around the battery tray across the front edge of the fuel tank to the other side, I'll have to get some 'after' photos but needless to say it now looks like new. I didn't do the repairs by the way, just my local garage who I have been using for years, not a Porsche specialist. Whole lot cost me £700 inc parts which included a new battery as well.

I would have tackled this job myself if were not for the lack of time, no garage and a distinct history of not finishing things.

[Airhead]

Nice work.....looks like they made the battery tray then, not many non-specialists who'll go to that sort of trouble these days!

Right I got the front pan in this weekend so just the tank support to fix now. A load more pics to follow but these will have to wait until I get time to upload them

[Bob_Salmon]

I am doing something similar so it may help other people who have to consider it themselves later on - these cars aren't getting any younger!

I only needed to replace the forward half of the pan and Mark at Roger Bray's assured me that was an easy panel to fit. Just the usual grind off welds etc., cut out the old tank support and line up the new pan half, using the suspension as a guide. The suspension will move sufficiently to get the pan in from beneath the car but I look forward to seeing how you got it in from above - I couldn't! Tack in place, check, re-check then weld up. That seemed to work fairly well although it took a lot longer to do than describe...........

Today I screwed a wooden beam across the top of the boot (used SS washers to get the width exactly right) so that the whole compartment was rigid, then I cut out the slam panel. This had to be replaced anyway and it made it much easier to weld in the tank support. Almost finished that with spot welds around the tank area and a mix of plug and seam welding elsewhere.

Rain forcast for tomorrow so that's probably as far as I will get this week but will keep you posted.

As a postscript. I have the car on a concrete drive under a scaffold pole frame and tarp covers because my garage is only just big enough to get the car in and impossible to work on it when it is. It's working fairly well but not practical in strong wind or rain (I guess I need more tarps) but not a lot of light there so welding is harder than it might be. Since I am at sea for much of the time and need the right sort of weather when I am at home, it might be a while before I get her back on the road

Bob

[Airhead]

right........next installment:

The rust was cut out and the area straigheted and prepped with weld thru primer. Not that small sections of the lateral tank supports each side have been removed in order to allow the pan to be dropped in from above. These sections had seen better days so cutting them out also alows me to clean them up before replacing or fabricate new sections as necessary.



Then an initial trial fit was carried out (first of many) and a few meaurements taken to see how it lined up (ditto) against dimensions published in the Haynes 911 Restoration manual and my own taken from the car before work commenced.



More prepping of the edges and holes drilled for plug welding with the MIG where spot welds once were.



Now the point of no return........notice from the trial fit pic that the pan was slipped under the existing metal where the join is to be made either side of the chassis rails. Once happy with the fit and positioning (this is where tacking the A arms in place is useful as it allows you to bolt the panel to it which helps A hold it in place for welding and B ensure correct alignment) I took a 1mm slitting disc in the drinder and cut along the line to be butt welded (leaves a perfect gap for this type of joint).



like so........first tack welding every 50mm to avoid distortion and then filling in with tacks one ontop of eachother working in a different place each time (again to avoid heat distortion) not as neat as a continuous line of weld but it will be ground off afterwards with a course flexible sanding disc anyway:



to give this



then I went round and plug welded the seams undeneath each side and 2 lines at the front one inside and the other outside plus a few other locations where I found welds when dismantling the original. After some tiger seal on all seams and a bit of primer to protect bare metal until the next installment it looked like this (note lateral tank support sections rested back in place to check fit in this pic:

[912uk]

looks good

[Airhead]

Final update

Lateral tank support sections that were cut out in order to fit the pan from above cleaned up a treat and were duly put back and welded up again:



Then to protect the inside of the box section created by the rest of the tank support I let rip with the tiger seal and then a coat of weldable primer for the areas to be welded which was masked off and the rest of the insides painted with anti rust zinc primer followed by a some shutz (aerosol type) and finally some hammerite wax oil to follow later........Am I being paranoid?





Then after a trial fit which revealed that the left hand side of the tank support (as you look at this pic) needed a little fettling as the raised edge on the original was some 5mm higher on the original though. This was easilly acheived in a vice though by re-assigning a fold or two in the metal and finishing off by offering it up and dressing with a hammer and dolly.
Tacked this in place and tried the tank in the hole. All was fine so it was welded in place using the MIG and plug weld technique.



since I dont have a compressor yet I carried painted the lot in some black hammerite and stippled some underseal on to make it look vaguely like the original and protect it while I get it MOTd. At a later date I intend to strip this do it properly though with the proper 2 part shutz gun sealant to match the original stuff.



Then back together one other pressing matter had to be seen to..........the front was too high

[912uk]

easy to adjust that jack up and turn down the bolts

Measure first and then count the turns.

M

= too high

= low'ish

= Low

= nipple scrapping low...cool

[domo1977]

Great series of reports mate! Well written with good photos! A++
Has inspired me to get on and finish fitting the new sills on my car!!