Skewoooot

I went to replace my rear coil-overs last night and found this unpleasant surprise. Anyone else had to deal with this? I searched the archives in several different ways without success.
The rust is concentrated on the thin back plates, which don't appear to be that structurally integral, but I'm assuming they exist for a reason.
Where can I buy these other than the dealer? I've checked all of my favorite online part sources and none carry them, so I'm tempted to just cut the rusted back plates off and coat the rest with an anti-corrosion paint.

5v/cyl

Have you tried calling around to junk yards for some used ones?

It looks like you can new ones here: http://genuineaudiparts.com/partloca...layCatalogid=0

I'm surprised at the amount of rust. I just had mine apart due to a broken spring and found none of that. I live in Michigan and they love to put out the salt in the winter, so you would think mine would be as bad or worse.

mtroxel

Minnesota here. My 96 had 270,000 miles on it and I didn't have that kind of rust. and they salt the hell outta the roads where too.

Skewoooot

5v/cyl, thanks for the part link. That was actually one of the sites I checked, but I guess I wasn't looking in the right place.

I did find them used, thru Dad's Auto (now BW), for only $50 per side, and they actually send the whole strut & spring assembly. Apparently they don't like messing with spring decompression. I was told they sell quite a few of these and they're located in northern California, so rust is rarely an issue on their vehicles. They assured me these will be rust free.

I'm at 160k miles in St. Louis (not garaged), and I bought it used in Chicago (where it originated) at about half that mileage. Both areas do use salt in the winter, but the rest of the car doesn't seem to show significant signs of corrosion, except for the H&R coilovers that I just removed. The springs and shock bodies are pretty bad, to the point where one of the spring perches was seized and couldn't be adjusted.

Lago Blue

BTDT. I was early, and just lucky. These can be easily D-I-Y protected with proper preparation, painting and rust-proofing. There is a drain hole near the upper spring perch that can become clogged with debris. Even the adjustable spring perches can be treated against corrosion. Part of the problem you mentioned about the inner skin, is that water salt and dirt can get trapped between the fender inner wall proper, and the subject part. This sets up a little battery, so treat it like you would a battery tray.

Some of the early cars appear to have a better quality paint on this part which may explain some of the good used ones that can be found.

Only because B4s (like mine) share their rear architecture with the B5s, am I familiar with this exact issue. That (model 90) forum gives you another place to search for discussions re. problems shared between these two platforms. For example (while your there at the rear upper A-arms):

https://www.audiworld.com/forums/sho...highlight=poor

Skewoooot

Your analysis makes a lot of sense, thanks for sharing. Do you know a good link that explains in detail your reference to "easily D-I-Y protected with proper preparation, painting and rust-proofing"? I've had very little experience with paints and coatings, so I'd like to learn some good methods for this to use on this application, as well as several other areas of my vehicle.