Front suspension pan - generic question

[Greg D.]

[begin short rant] I am sooo *never* buying a car long distance *EVER* again, even if the seller is endorsed by the Vatican [/end rant]

I have been patching a hole in the battery box on my supposedly perfect 68 912, thinking the damage was contained there, but the more I dig, the more I wonder.... Yesterday as I put it on the lift, i noticed that there might be some perforation issues near the front attachment of the A arm. Not swiss cheese, mind you, but some weird patch work and stuff that looks like some potential holes near the welds of that patch. I don't mean to ask for an definitive opinion without showing pictures and digging further, but from your experience, it it possible (reasonable / "done" / accepted practice) to unbolt the A arm, and just cut out and patch that area near the front A arm (say 8 sq inches) and not do the entire pan replacement if the rest is sound? Not sure if that's accepted practice or if it's a big no-no for some obscure reason or suspension alignment maybe... it does not seem widespread, just under where the acid leaked and artfully hidden under a coat of shutz...

Another nice surprise was the otherhwise pretty repaint ending at the very edge of the door trim by the window... who the $$#% does that ? It takes 5 seconds to lift the trim and paint the whole thing !!! oops, still ranting, sorry ;-) I need a mojito...

[Esposito]

Greg, It's not good to section in a piece of the pan.
The main reason is when you weld in the new piece, you are creating a rust issue.
The welding process itself is an oxydizing process.
The inside of the pan will be burned where you weld in the new piece.
You can try to treat it with a zinc rich weld through primer, however, It is not for that use.
My experience with pans is, if you have a rust hole, the entire pan is probably junk.
If you would like a better explanation, you can give me a call at 818 469 1811.

John Esposito

[304065]

Greg,

Welcome to SWB ownership! Look under your computer keyboard, can you see the rust beginning to form?

If I had $1 for every time I heard the old "battery leaked" line from a seller about the rust pervading the front pan and gas tank support I would have enough to buy a 911R. What usually happens is that the hollow areas in the pan fill up with water over the years, which rusts the forward suspension mounting points from the inside out. If one is gone, the other one is not far behind. I drove an otherwise nicely restored car that had this situation once, it drove OK, but I could never enjoy the car because I was always wondering when the front suspension point was going to give out. This can kill you.

So the correct way to do it is to change the entire pan. Changing just a piece is asking for trouble when the other side or the structure fails, rust doesn't happen in one place. This is such a routine replacement in our cars that it's not even considered major surgery these days. A few road tips:

The REALLY correct way to do it is to put the car on a Celette bench so that alignment can be assured when the welding is complete. Guys do lots of pan repairs without doing this and just use the A-arm to align the pan, which can result in it being welded on crooked or binding of the suspension. I accept that not everyone has access to a Cellete however it's worth seeking out a professional for the job. This is why I hauled 065 five hours away to Series900 in New Hampshire.

The repro pans are good, the factory pans are better. If you put an RD pan on the Celette by itself you can see how it doesn't quite lay flat, it's got preload in the stamping. The factory pan lays flat across the suspension pickups. '

The modern gas tank support piece has a circular depression in the middle of it, a prominent "bump" on the forward side and no provision for the factory battery mount. You see modern pieces with these deficiencies present with a piece of metal welded on for the battery, this has to be removed, the depression filled and the bump removed, and then the battery piece goes back on.

Once you get it done, the whole thing can be schutzed and then Wuerth cavity wax used to fill up the internal structure so it won't rust again. The factory never did the internal rustproofing and 40 years later it shows.

Now about the repaint. . . Good luck, remember that many have gone this way before, you're not alone.

[jesseandersson]

You could open the upper support and have a look and then decide what to do, easy and cheap to put in a new one if it´s all ok.

Daryll did a good job, http://www.darrylsgarage.com/912/912rust2.htm

Lots of good pics there!

[Greg D.]

You could open the upper support and have a look and then decide what to do, easy and cheap to put in a new one if it´s all ok.

That's kinda where I'm at... The hole is not that big, and there is rust inside, but it seems to be (internal) surface stuff... i will open it wider and poke hard...

[little b]

my battery box looks great. But when i removed both suspension A-arms, BOTH had rust holes. just like what 304065 said.....factory never rust proofed, and water got up inside. a common problem. my whole pan is getting replaced as we speak.

[JohnT]

Now you have the satisfaction of knowing exactly when and how well the repair was done!

[curtisaa]

Greg, It's not good to section in a piece of the pan.
The main reason is when you weld in the new piece, you are creating a rust issue.
The welding process itself is an oxydizing process.
The inside of the pan will be burned where you weld in the new piece.
You can try to treat it with a zinc rich weld through primer, however, It is not for that use.
My experience with pans is, if you have a rust hole, the entire pan is probably junk.
If you would like a better explanation, you can give me a call at 818 469 1811.

John Esposito

"spot on John"...take this advice and go down the road. He is 110% correct.

[EARLY911ZOO]

here's a pan that looked and felt solid until I got rough with a pick. they rust from the inside out.

[EARLY911ZOO]

and replaced correctly!