Warning: Rear frame rail rust due to bizarre engineering failure...
11-07-2013, 12:31 PM
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Warning: Rear frame rail rust due to bizarre engineering failure...
For some idiotic reason, Porsche decided to bolt in the rear fender/tail panel brace, and then undercoat over the bottom of it. Worse yet, not only is the top left completely open, but they even stamped in a pocket! It's literally designed to catch water!
Unbelievable. Needless to say, this discovery held up the reassembly process for a bit. BIG thanks to friend and fellow Rennlister krisedwards for volunteering to help with the repair. I can weld, but I can't do anything like the quality of work that he does.
The worst problem is that the rust is pretty much completely hidden. If the bumper brackets had not been destroyed, I would never have pulled the muffler heat shields, not unbolted the brace. There was no external indication that anything was wrong, which is always nice. Basically, if you've got the bumper off, I HIGHLY recommend doing a little digging here. You do not want this to grow.
Pics to follow...
Unbelievable. Needless to say, this discovery held up the reassembly process for a bit. BIG thanks to friend and fellow Rennlister krisedwards for volunteering to help with the repair. I can weld, but I can't do anything like the quality of work that he does.
The worst problem is that the rust is pretty much completely hidden. If the bumper brackets had not been destroyed, I would never have pulled the muffler heat shields, not unbolted the brace. There was no external indication that anything was wrong, which is always nice. Basically, if you've got the bumper off, I HIGHLY recommend doing a little digging here. You do not want this to grow.
Pics to follow...
11-07-2013, 12:42 PM
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When I saw this, I was understandably rather upset. I gave Kris a call, and he volunteered to help repair it. (In this case "help" largely meant dig into it - I don't have the skill to work anywhere close to this level.) I looked at purchasing replacement panels, but that opens up a whole new can of worms, and at $2,000 per side, wasn't an attractive option. The only downside is that his welder is, uh, most emphatically not portable, so we had a very European repair experience. Kris' garage is not actually wide enough to open the doors in.
Fitting the driver's side:
Fitting the passenger's side (I spent much of this time fixing Krispy's truck - it seemed only fair, but meant that here were not so many pictures. I have multiple facial injuries from flying rust chunks, however!):
Sigh. Removing the DME:
Getting the seat out was FUN in that garage!
Fitting the driver's side:
Fitting the passenger's side (I spent much of this time fixing Krispy's truck - it seemed only fair, but meant that here were not so many pictures. I have multiple facial injuries from flying rust chunks, however!):
Sigh. Removing the DME:
Getting the seat out was FUN in that garage!
11-07-2013, 12:46 PM
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Welding!
Mounting studs tacked in:
Driver's side "final" fitment (sheet metal flexes when heated, so it's a constant adjustment process):
Welding it in:
Nice and clean!
More importantly, look at the penetration!
Mounting studs tacked in:
Driver's side "final" fitment (sheet metal flexes when heated, so it's a constant adjustment process):
Welding it in:
Nice and clean!
More importantly, look at the penetration!
11-07-2013, 12:53 PM
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Passenger side final fitment:
It's safe to say that I was PUNISHING my iPhone's camera for this process.
Phosphalyzed for paint:
I rigged up a wand on an undercoating gun to paint the inside of the rails. It'll be interesting to see how well that turned out when I stick an endoscope up there.
Net-net, this is something that really, really should be checked. I'm trying to decide what I'm going to do when I reinstall the brace. My general inclination is to fill the whole cavity with either seam sealer, or a bonding compound like 3M Automix 08115 to keep water out permanently.
It's safe to say that I was PUNISHING my iPhone's camera for this process.
Phosphalyzed for paint:
I rigged up a wand on an undercoating gun to paint the inside of the rails. It'll be interesting to see how well that turned out when I stick an endoscope up there.
Net-net, this is something that really, really should be checked. I'm trying to decide what I'm going to do when I reinstall the brace. My general inclination is to fill the whole cavity with either seam sealer, or a bonding compound like 3M Automix 08115 to keep water out permanently.
11-07-2013, 01:42 PM
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Nice work. Was your car driven in the winter, exposed to salt and such?
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11-07-2013, 02:09 PM
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Nice repair 
. You are now qualified to own a late 60's 911. I think this has been discussed quite a bit over on the 993 forum. Poor design to say the least.
. You are now qualified to own a late 60's 911. I think this has been discussed quite a bit over on the 993 forum. Poor design to say the least.
11-07-2013, 02:37 PM
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11-07-2013, 02:41 PM
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I mean, we are talking about primer, then undercoating, then paint, then brace, then heat shielding. From the top, the bumper will cover it, IIRC. There's no compelling reason to grind the welds down that I can see. And grinding welds down is generally poor practice when not necessary.
