240D rear lockup
 

I'm a new subscriber looking for some help troubleshooting a rear lockup. During a left turn through an intersection, my daughter felt the car veer left and she overcorrected, running up onto the curb. I was dispatched to the scene, and after changing both right flat tires (from jumping the curb) the car wouldn't go more than a foot in either reverse or forward without locking up. I had it trailered home and tried to turn both rear wheels independently...the right rear was difficult, the left easy. I suspected the right rear because of the skid marks left from my attempts to move the car before the tow truck arrived. When the truck arrived, the car would move but was making clunking noises from the right rear.

The car was trailered home, where I pulled the right axle shaft. The outer wheel bearing rolls easy without notchy feeling, as does the differential bearing. No metal filings in the differential housing or oil.

The outboard CV joint feels notchy (as I believe it should) and stays off-center when released from that position. The inboard joint is sloppy and stays on-center when released from off-center. I believe the looseness would result in noise or vibration, but not lockup.

Would the bearings have a smooth feel and still be bad, because there is no load (on jackstands)? Am I missing a typical source for problems?

Thanks for any assistance,
Paul Jones

Did you check the ring gear and pinion gear? The left side could move freely and still have a jammed up ring and pinion because of the differential gears or Spider Gears as they are called.
The axles will move independantly of each other because of the spider gears - unless they are turned upside down making it a positive traction rear end. Or welded. Which I am sure the latter is not the case.
More than likely when the right wheels hit the curb it drove the axle into the pider gears and may have locked up there, possible broken gear hub (Spider gears mount into a hub).
I doubt there is a thing wrong with the axle or the bearings. our problem lies in the center pig. Center Casing. That is Aluminum, might want to check for cracks.

I'd also just check the emergency brake--they lock up sometimes. Your problem sounds more serious, but wouldn't hurt to check the brake.

Sounds like by removing the axle shaft, you have eliminated the bearing and the emergency brake. A bearing that produces lockup with load would still sound/feel lousy without. Did your inspection of the axle find the rubber boots in good condition? If so, I doubt it is the the axle, but it still could be. Since you pulled the axle, you must have the differential rear cover removed? You need to turn the differential to check its function. You could put the axle shaft spline back into the differential and try to turn it (leave the wheel end out of the wheel spline). It should turn easily with the spider gears orbiting the differential.

Good luck.

Good luck.

240D rear lockup
 

I described the problem to my local independent shop. He asked what style rim the spare had that I installed on the right rear. The car has MB alloys with a steel spare. When I told him it was a steel rim, he said the alloy rims use a longer bolt and when used with a steel rim they can catch on the emergency brake mechanism, preventing the wheel from turning. When the tow truck arrived, I had probably broke something loose which allowed the wheel to turn but still make noise.

I checked out his theory and he was right on. The wheel bolts were scarred on the ends and the cable end/bracket of the emergency brake was gouged on one side. I will carry a set of shorter bolts in case I flat.

I am glad it wasn't anything more serious. At least my differential fluid got changed out and I can rest easy knowing the rear end is in fairly good shape.

Thanks for the responses I received from this list.

Paul Jones
'84 300TD, '80 240D