420 SEL Rear Suspension Problem

[Inthemedia]

During an icy spell, I managed to run the right rear tire of my 420SEL into a curb. The rim was sufficiently bent/gouged at the bead to warrant replacing it since it would no longer hold air. While I wait for the new rim to arrive, I put the spare on which appears to be the identical alloy rim. Now whenever I hit a hole or a rough patch of pavement, the rear end seems to bounce in a series of jarring small bumps and the rear end looses traction causing the car to momentarily jump sideways.

The questions I have are: Is toe-in, caster, and camber adjustable on the rear of these cars and could one of these now be out of adjustment? Could I have bent the bolts securing the trailing arm to the body? Could I have actually bent the trailing arm or is this impossible to do? Thank you.