w123 passenger side rear trailing arm (control arm) swap - PeachParts Mercedes-Benz Forum

gunz84 300d · #1 01-06-2017, 03:03 PM

Hi guys,

w123 wagon has been diagnosed with failed control arm bushing on the passenger side. It is also bent from PO accident so I am gonna swap the whole arm and put in new bushings.

I've gone through the threads and see alot of guys doing both at the same time and so they dropped the whole subframe.

Is it possible to do just one side at a time, in this case passenger, and leave driver side in tact and attached?

vonsmog · #2 01-06-2017, 06:00 PM

I don't think you can get to the bolts without dropping the sub frame. At least you can't on the R107's. I did my 84' 380SL last spring, and just dropped the sub frame, replaced all bushings and mounts all at this time. It is very easy to drop the sub frame, so best to do both sides. If one is bad, how good can the other side be? I have good trailing arms and sub frames if you need any parts let me know.

ROLLGUY · #3 01-06-2017, 10:27 PM

I did it on my friends wagon, but subframe bushings were part of the job, so the whole subframe had to come out. However, I can't see why you could not remove the rear diff mount to allow the subframe to drop down, giving enough room to access the bushing bolts. If you loosened the front subframe bolts, that would give even more room to get the trailing arm off without completely removing the subframe or diff.

gunz84 300d · #4 01-09-2017, 08:54 AM

I see, I suppose I should go for bushings on both sides while doing arm swap on the passenger side.

As I sit here I am trying to picture dropping diff (by removing mount), subframe bolts (probably exhaust on driver side) to get access at both sides control arm bushings. Then (or rather before jacking rear end up) disconnecting SLS strut and compressing spring on passenger side for removal of that arm completely (and axle nut, etc).

I did the subframe mounts about a year ago, that was a nightmare as the bolts were all seized in the bushings. I sheared two 1/2" driver heads off before I cut/melted the rubber bushing so the bolt could spin out of their threads.

Anyway, if the subframe can largely stay in place during this I'd imagine my life would be somewhat easier. And if it wasn't 5F this morning!

ROLLGUY · #5 01-09-2017, 11:49 AM

Quote:

Originally Posted by gunz84 300d

Anyway, if the subframe can largely stay in place during this I'd imagine my life would be somewhat easier. And if it wasn't 5F this morning!

I think it can if only the trailing arm bushings will be replaced. That way you don't have to remove the diff either. Just loosen the two front bolts, and the subframe will droop down enough to get the springs out and give access to the trailing arm bolts.

charmalu · #6 01-10-2017, 02:04 PM

How ever you go about doing it, I would recommend to remove the calipers and hang them up with a piece of wire.
Otherwise when the SF is lowered, the rubber brake hoses will be stressed.

When I did the 85 300D, I removed the whole assembly.
Cleaned up (Degreased) and sanded down things, and POR`d it all.
Trailing Arms, Sub frame, made it all Purdy.

I swapped in a lower mileage set, along with the Differential.
Replaced TR bushings and SF Mounts, Diff Mount and Spring Pads.
Really tightened up things. I also found some Progressive Springs at PNP and swapped them in.
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