Corossion on Rear Chassis..
 

Folks , I've meant to log this thread for a while here , sorry I've not been posting as much as I used to , I'm not getting as much time for these matters as I'd like!
Sorry if this is a re-post , I tried the search function for 'corrosion' but got nothing like this up...


I had my 993 down at the bodyshop a few weeks ago, arranging to get the alloys refurbed and a spot of rust under the rear window dealt with. I'd chosen this particular bodyshop as he specialises in Porsches and has had recommendations from a number of 993 owners in recent times.

To the real point of the thread , he asked me if I'd had my rear chassis arms checked out... HUH!!? .. I'd heard of a problem in this area from my local indie but didn't quite get it ; so Paul Stewart (the body shop guy) started showing me pics of work he'd done on about 4 other 993's.

Apparently , when sealer was applied at factory , one section was missed out and has become a haven for the tinworm , but can't be seen unless , firstly the rear PU is taken off , and then a side support to the rear chassis leg is removed. On each of the cars he's checked , it's been riddled with rust and only going to get worse, needs a new bit welded in and new 993 bumper support plate (as opposed to bumper support arms , which many of us have changed anyway) need replacing , they cost £80 each (one for each side) from the friendly opc.

Well I got him to strip my PU and have a look to see if this needs doing in my car . I also asked him to take photos, which you can see below .

You need new some support arms , (see pics below) to do the job properly.

The long and short of it is that if you're planning on holding onto your 993 , really this will need to be done , otherwise the rust will perforate the chassis legs and spread inside the legs making for a big bill in the long run. At the moment , changing the support arms and doing local repair work to the legs is coming out at about €750, but that 's an approximate price depending on how much rust is found..

Sorry to be a bringer of bad news folks , but the silver lining is that Paul has stripped a number of 993's and knows them intimately at this stage , and reckons this is the only area of the chassis he's seen that will go this way , he reckons they're very well protected besides ..

Some pics..

Here's my new support plates before they were installed..

https://i231.photobucket.com/albums/...e/da02f91a.jpg

This is the offending area before the support plate comes off on another owners 993 .. Note you can't see any rust at this stage , it sits behin the plate as the plate hasn't been factory sealed properly..
The plate is the part sitting horizontally just above the muffler in the pic below..

http://911uk.com/files/p1000734_132.jpg

A close up of a support plate as our 993 owner strips his car to check the condition of his chassis in this area.. Rust beginning to show :surr:

http://911uk.com/files/p1000736_183.jpg

This is , unfortunately what he found underneath the support plate; the chassis leg has been perforated , needs to be fixed ASAP..

http://911uk.com/files/p1000740_101.jpg

Well here's the pics from my car , and the work that was done..

https://i231.photobucket.com/albums/...5/ffda0b3a.jpg


https://i231.photobucket.com/albums/...5/d7012111.jpg

Passenger side , just surface rust .. The least affected the bodyshop guy had seen!! .. Note all that silt lying on top of the rusted area , this stuff just sits there penetrating into the chassis legs..:grr:

Old V's New brackets...

https://i231.photobucket.com/albums/...5/31711143.jpg

https://i231.photobucket.com/albums/...5/e0fdaae5.jpg

Underseal can clearly be seen just by the thumb on the above pic ... No underseal along the rest of the top edge tho , letting moisture and rot in.
The work involved an underseal from the inside first , then do it on top , include priming , painting , this sucker will be the way it SHOULD have left the factory in the first place...
I also waxoyled the inner chassis members while it was exposed , should keep me driving happily for many years!


Finally some pics of the work done .. Fabrication..

https://i231.photobucket.com/albums/...e/11302e9e.jpg

https://i231.photobucket.com/albums/...e/89436b02.jpg

Final job , underseal on bracket .. Check!
Stonechip .. Check!
Paintwork .. Check!
Waxoly .. Check!
https://i231.photobucket.com/albums/...e/3690ff28.jpg

https://i231.photobucket.com/albums/...e/ebfb076d.jpg


Folks , I'm not tryng to alarm anyone , or get people worried .. I know that there's loads of you guys here who (like me) fancy our 993's as looong term cars ,so I thought you'd appreciate a heads up on this topic.

Although a bit scary, posts like this are great information. Thankyou!

Excellent thread. Numbing, but informative.


Andreas

Thank you for pointing this out, I'm gonna take a look on mine...

I sense a "Winter 2011 cleaning and investigation" thread on the horizon.;)

Cheers guys , I assure the post is meant purely as an informative one rather than wanting to alarm anyone.
I've done a lot of research on this topic and can tell y'all that most everyone who checked found at least surface rust in these areas ... Tho it may be a different tale for those of you in drier climes. Hopefully!!

I seem to recall there was a similar rust perforated area in the 9m buildup thread.

Well after this thread and the 9m thread I was freaked about mine.

Here is what I found and my advice to others during inspection:

From the outside it looks ok but it looks different than yours. There is no color painted, just the white primer. It felt solid and I was not sure about pulling the mount free and splitting the original primer.

http://i955.photobucket.com/albums/a...ath/primer.jpg


I was still curious and took it loose anyway.

http://i955.photobucket.com/albums/a...undermount.jpg

As you can see no rust:jumper:
But there is unpainted metal around the studs, I guess mine was sealed good enough not to let in water. Lucky I guess.

The mount was still in good shape, the same exposed metal in the center around the stud holes.

http://i955.photobucket.com/albums/a...eath/mount.jpg

I got the other side loose and it was pretty much the same.

If I were starting over I would have left the original mounts in place, I was pretty sure from looking at it and tapping on the mount that there was no rust behind it. I would have just cleaned all the road grime off the top and made sure the top was sealed along the seam.

So I will clean it all up and paint the stud area, then seal the seam at the top of the cover, it should be good for another 17 years.

Sorry for the rust damage on your car but I am glad you posted for others to learn.

Excellent!


Andreas

That's excellent news Erik!

I hope it works out just like that for you guys over there.. It's not pretty , but at least it's not the end of the world either as it's easily fixable.

Erik , have you had your car long , and was it garaged during most of its life?


I'm still trying to figure out why there's a huge difference in the amount of perforation across the 'fleet'..
A pal of mine with an Irish car from day one had the worst case of perforation on the chassis legs , which really surprised us all..Cos there was no salt used until 2 years ago on Irish roads. However , it's more normal for Irish cars to be parked outside than garaged, so I was wondering if this was a factor...

I have had my car about 18 months?

It was a one owner car, he was in the air force and the car was all over the east coast. From records it was probably a daily driver in Georgia, North Carolina and New York. Then the miles tapered off in the early 2000's as it became a 3rd car and he moved to Kansas City. The front and rear windows have had repairs to the corners and there is some light corosion on the fasteners under the car but no rust anywhere else.

So I would say it was exposed to some light amounts of salt/deicer early on but always ended up cleaned off and the interior was in really good shape so I imagine it was garaged all of it's life, that is what I think from my inspections anyway.

Although it is bad to see the rust damage to your car, I have to say the shop did awesome work on the repairs. Way better than factory IMO.

Hopefully everyone else that looks has good news!

OPC and PU must be UK terms. Can someone translate?

OPC = Original Porsche Centre (Dealer)

Good to see you "back" Barney, and interesting thread.

Did you do some interesting flying last week? :D