I couldn't find anything about it in the archives, but someone else out there must have experienced this:

The plastic cover over the rear bumper on my '92 245 has become distorted so that there are slight bulges on the top of the bumper. Aesthetically it's not the end of the world, but the bulges are pushing the bumper trim against the tailgate, causing scratching on its bottom edge. Consequently, rust is creeping up the back of the tailgate from that spot.

I've seen rust on other 245s in the same spot (driver's side mostly), so I'm thinking it's a common condition.

My guess is that the bumper is corroding under the plastic cover and that's causing the disortion, but taking the cover off is kindof a PITA so I was hoping for advice before I did so...

Any information on the subject would be appreciated.

If your bumper is anything like the bumper on my 83 wagon, it is an aluminum channel under the rubber cover, and it is not corrosion, but some minor "bump" that has caused the distortion.

By "bump" do you mean an impact? Are you trying to say that I'm a poor parallel parker? ;-)

Thanks, that answers part of my question... now what to do about it. Probably my best option is a junkyard, as the part new would be worth almost as much as the car itself.

I'm wondering if a heat gun would massage the bumps out...