Drivers Side Rear Grating 450SL
 

This irritant started about a week or so ago. When exiting my parking ramp I noticed a squeaking sound coming from the rear drivers side wheel area as I turned right to go down the exit. The sound got progressively worse over the next days/week. Now, there is a metal scraping sound coming from the same area. This sound comes and goes while driving - a couple of minutes on and a couple off - it seems to be a slower sound that one that would come with every revolution of the rear wheel. I've searched the forum and think it might be the u-joint. Does this sound right? Although I am capable of some repairs myself, this one has me concerned that whatever it is is beyond my abilities. Any suggestions on troubleshooting techniques to isolate the problem? If I have to take it in to the local MB dealer I would like to have identified the problem. Also, do you think it is safe to drive the 10 miles to the dealer? It's a 1976 450SL that otherwide runs super.

Sounds to me like it could be your rear axle bearing. My 450SL made the same noises. Had to replace both sides within a few months of each other. Should be safe to drive to dealer but the longer you drive the car with the noises the more wear the bearing puts on the axle tube. And soon you will have to replace the tube as well as the bearing. You might consider doing both bearings at the same time. Usually if one goes bad the other one is just a matter of time.