What should I check to see if rear subframe bushings on W123 are bad?
 

What should I look for when inspecting the subframe bushings to see if they're bad on a W123 chassis? I've come across some threads in the past but haven't had much luck in locating them again. What would the signs be when driving the car and are they hard to replace?

Look at the picture in this thread.
 

Anyone ever broke a rear subframe bushing bolt?
http://www.peachparts.com/shopforum/diesel-discussion/73580-anyone-ever-broke-rear-subframe-bushing-bolt.html?highlight=subframe+bushing

Yes. Fortunately, it broke off just below the head. I ended up cutting the rubber part of the bushing away from the metal insert so I could heat the broken bolt with a torch. Heat and penetrating oil did the trick to loosen the bolt; I hammered a 15mm impact socket onto the bolt shaft and used that to turn it out.

Both bushing inserts on this car had seized to the bolts. I think that's what I was fighting when I broke the bolt head off.

BTW, In addressing lietuviai's question about inspecting the rear bushings for failure, I'd try jacking up the subframe arm near the bushing. If the bushing shows a lot of elasticity and the subframe arm has a lot of free movement, I'd say that's a pretty good sign that the bushings are done for.

Russ M

I don't have any rust on my car but it's things like breaking that bolt worry me since with my luck it'd break in the worst place.

Answer:
 

Bolts are cheap... :)

Yeah they are but my patience to remove a busted one isn't. :D

The second bolt was easier than the first (isn't that usually the case). On the second one, I used a Bosch Roto-Zip bit to carve on the bushing before I made a serious effort to back out the bolt. The Roto-Zip bit is an excellent tool for this job, kind of a rotary jigsaw blade.

After a little carving, I was able to loosen the bolt enough that I could rotate the skid plate that blocks direct access to the bushing. From there on it was easy: cut, rotate, cut. Once I'd worked my way around the circumference of the bushing hub, the bolt came out with only a little objection.

That left me with a skid plate attached firmly to the bushing core, since the bolt was seized to the bushing sleeve. I ended up using a cutoff disk (well, several) to open up the sleeve and free the bolt.

This was not a salt belt car ('82 300td), by the way. I bought it in Atlanta, and I'm familiar with its history. It's got a couple minor rust spots but nothing compared to the contemporaries I've seen up here in Wisconsin. I wouldn't have put the effort into a rustbucket. In all I spent about 10 hours on this project.

Oh, and I have an '82 coupe from Los Angeles -- BOTH subframe bushings took about an hour to replace on that car.

Russ M