How hard to replace front pan?

billd · 04-03-2006, 10:32 AM

I'm looking at a 69 911T that is in OK condition except for a large rust hole in the front pan. How hard is it to cut out and replace the front pan and gas-tank support?

If I were to pay a body shop to do this how much would they charge? If I were to do it myself, are there any special issues I should be aware of?

Thanks,

----Bill

Rot 911 · 04-03-2006, 10:59 AM

Not hard to do if you have a MIG welder. Costs around $800 to have someone else do it versus $500 for a decent MIG welder and $200 in parts. Which is why when I had my '72E, I bought a MIG welder and did it myself. Lots of people on this board have done it. Plenty of threads to search through and lots of advice from those of us who have done it!

billd · 04-03-2006, 08:44 PM

Thanks for the reply. Can you point me at a good thread that describes the process.

sammygon1 · 04-04-2006, 01:58 AM

Try this link: http://www.hillmanimages.com/912/jesse.html
It's a 912 but you get the idea. Also just type in front suspension pan replacement int he search and you'll find a bunch of stuff.
Good Luck,
Sam

Willem Fick · 04-04-2006, 04:28 AM

Real easy to do! Didn't have a MIG, but managed quite a good job with Oxy-Asethylene. As long as you make sure you align the panels correctly you can't get it wrong!

stormmaster · stormmaster's Garage

Please tell me you did more than braze that panel in the front of your car....These are unibody cars....made with materials that become very brittle when subjected to the type heat created with Oxy-Asethylene torch...you cannot control the heat like you can with a MIG welder...and the joints are not near as strong.

ruf-porsche · ruf-porsche's Garage

First off you don't cut off the pan. You need to drill out the spot welds. You can buy a cheap spot welder or spot welder attachment if you already own a welder.

Lotsa info if you search this board or google Porsche pan replacement.

Willem Fick · 04-04-2006, 05:17 AM

Stormmaster,

No, didn't braze! First spot-welded it every inch or so to make sure alignment was sorted out, and then proceeded to weld it in with a filler rod, doing a short section at a time only, allowing it to cool, and adjusting for warpage all the way. Used up quite a bit of gas, but the end result is perfect!

As for the brittleness - this only becomes an issue if you try to weld over an area that was previosly contaminated with brazing. I had the misfortune of working on a car that had previously been brazed in places, and ended up having to replace quite a bit of sheetmetal, to fix this.

IMHO, a good oxy weld is stil years better than the original spot-welds!

na2ub · 04-04-2006, 06:51 AM

Not hard, but labor intensive. It took me many hours. Drilling out the old spot welds and cleaning off undercoating accounted for most of those. Get a few drill bits of the hardest metal you can find. A drill sharpener may help too. I used a dremel to sharpen the bits as I went. This was my first "panel" replacement and it went quite well overall. Get the Haynes Restoration Manual - Porsche 911 for reference. It provides some good reference measurements for the new pan placement. Make sure you measure longitudinally and diagonally from the crossmember bolts to the front suspension bolts, many times so when you stick the new pan in you can get it square.

Doug

billd · 04-04-2006, 08:21 AM

If the rust is localized, is it necessary to replace the whole pan, or can I just cut out the rusty area and weld in a patch?

randywebb · 04-04-2006, 10:58 AM

Is brazing bad? I thought it was lower temperature method of joining metals.

Willem Fick · 04-05-2006, 11:49 PM

Randy,

Actually not at all. In fact, a brazed lapjoint is extremely strong, and compares well to a butweld in thin metal sections, in as far as strength is concerned.

It does cause problems if you want to weld later on, as the high temperature required will cause the brazing material to be taken up by the base metal, causing brittleness. To remedy this, you have to remove the entire brazed section, and replace it with "clean" metal.

rob justice · rob justice's Garage

Drill out the spot welds using a 'spot-weld' removal drill, don't use a standard drill. A spot-weld drill has a flat head and only only removes the weld from one panel. Saves a lot of time and produces a far better job.
Most motor factors sell them and they cost hardly anything.