w123 / w126 rear trailing arm bushing replacement, without removing subframe - PeachParts Mercedes-Benz Forum

badgator · #1 07-28-2014, 07:09 PM

I did it on my 300D, I think it will work on w126's also.

use care when working under cars, a couple spare wheels should under car as a backup in case it falls off of jackstands,
loosen wheels,
chock both front wheels
jack up car, use jack stands with wood under rear jacking points,
mark DS/flex joint, DO NOT have parking brake on! you need to remove the DS

driveshaft- need to move rear out of the way to remove inner arm bolt
loosen front DS sleeve (30mm)?,
13mm center bearing bolts (I only loosened a couple turns),
remove flex disk bolts on rear end flange
pry ds off of flange, will only drop a few inches, will need to move around to access inner arm bolts

loosen 15/16 or 24mm inner arm bolts w/3' pipe - check condition of spring shims on top of springs while you're down there

loosen both sides subframe, remove bolt on the one side you are working on, remove wheel.

wedge piece of 2x4 under sf, loosen outer arm bolt, remove inner bolt then outer, you will need to pry/push the arm/hub assembly back 1/2"? to go past limit stop?

I did use a bottle jack under the arm to limit the drop, but the shock holds if from dropping to far, no need to take off to shock bolt, remove 2x4 on top of sf, jack sf back up to access bushings, use 2x4 between sf and arm to gain enough room to press bushings out and in.

trim rubber around large end of bushing so it can be pressed out, press bushings out and in, with home made tool, use dish detergent to lube new bushings (I used my impact wrench, worked smoothly) use drilled out washer that doesn't contact inner bushing and install new bushing, only go in until the rubber shoulder contacts the arm, do not go too far

now is a good time to replace subframe mounts, if needed

reassemble, jack up arm near hub to preload arm before torqueing arm bolts down

tighten both sides of sf bolts, I did use a bottle jack under a ratchet to get bolt started, only light pressure is needed, and had a nut inside of socket so it was pushing the head of the bolt up, not the sf bracket

replace rear ds, tighten center bearing bolts, and large ds nut, remove jackstands, tighten wheels

homemade tool-
1 1/2" iron pipe coupler homedepot $8
8" 5/8 bolt, I used a carriage bolt because it had more thread (or allthread)
5/8 coupling nut (long)
assorted large washers
one washer needed to be drilled to go outside of the inner metal sleeve when assembling - you don't want to press the new bushing on using the inner sleeve, it will stress or tear the rubber - see picture, used a step drill

It took about a hour to unbolt arm and press out/in bushings on the last side today, now that I figured out how to do it.

I used LEMFOERDER German bushings $8.07 ea, from RM european

brilliantblue · #2 11-07-2016, 09:47 PM

Necro-bump thanks!

Anyone out there had successful use of this? I'm considering replacing subframe bushings with subframe still on the car and this seems like a workable how to.

thanks for any additional information or help!

Mercedes Man · #3 11-19-2016, 06:37 PM

brilliantblue,

I just completed this job today on my 1984 300SD with the instructions given. It is a difficult job because of the need to reposition the trailing arms, remove drive shaft, and re-seat the sub frame. My car is a California car since new, so there was no rust on anything. All my bolts were like new yet. It could be even been harder if any of the bolts were rusted in.

I bought parts from Pelican, including a new differential mount.

Some notes:

I built my own tool. I bought the parts at Home Depot:

5/8-11" X 7" Hex Bolt ZP - $2.25
Hex Nuts-USS 5/8 $0.35
5/8 IN Bearing Plate Washer $0.98 (from lumber yard)
2"X3" GAL Nipple $4.51 (from electrical)

+ a spacer (I used an old nut or what ever you want to use)

The instructions were recommending 1 1/2" iron pipe coupler. If use you 1 1/2", you will need to trim the old bushings. The bushings do not fit nicely inside 1 1/2" You really need 2" which is only available in the electrical department. This is really a great tool for the job and money will spent! It works as good as a commercial version!

I used 2 jack stands, 3 floor jacks and 1 bottle jack.

I had air an impact wrench and air ratchet - highly recommended.

I had deft pins to line holes up.

This is also a two man job. You probably could do it yourself but it would take a long time.

I disconnected the differential mount and supported it with a jack.

I did not remove the wheels.

The sub frame mounts did not want to bolt. The "bullet" bolts were supposed to line everything up, but they did not not. I used the bottle jack to seat the bolt into the body until the bolt went bang.

The driver side inner trailing bolt will come out without removing the drive shaft, but the passenger side requires the removal of the driver shaft. The bolt will hit the flex disk.

For the W126, you will need to remove the muffler and heat shield.

I could not pry the flex disk off of the differential. It has to go back about 1 inch to clear the pin. The drive shaft nut must be loosened. The drive shaft nut is very large and I do not have a wrench for it. I used Channel locks to unloosen it.

There is no worry that the spring will fall out in the process. When you have the trailing arm bolts out, you can grab the trailing arms with your hands and moving them around.

Hope this helps.

JHZR2 · #4 05-13-2020, 08:13 PM

Quote:

Originally Posted by brilliantblue

Necro-bump thanks!

Anyone out there had successful use of this? I'm considering replacing subframe bushings with subframe still on the car and this seems like a workable how to.

thanks for any additional information or help!

I’m curious if the same. This is a good pair of DIY, but it seems like most of the work is actually only required to get to the bolts that hold the trailing arm bushings in. Is that accurate? It would be great to renew the bushings on/in the car...

Diesel911 · #5 05-14-2020, 02:28 AM

Concerning the trailing arm bushings on a w123 I don't remember if is a wiki or just in the repair links bet there is a better thread by a member with dan in his member name.

I changed the Sub Frame Bushing by lowing one side at a time. I remember having difficulty getting one of the bushings out. It took a lot of prying.

Getting at the passenger side inner training arm bolt I had to remove the Driveshaft from the differential and in the process I ruined the Drive Shaft Support Rubber. So be sure to remove the bolts from that and be carful when you remove the shaft from the differential.
So I ended up pulling the whole drive shaft and also replaced the centering bushings on the drive shaft.
There is 2 attached pictures one showing the issue with the passenger side inner trailing arm bolt and the other showing how I supported things for the trailing arm bushing change. (I have a lot of jacks!)

Repair Links
Fast navigation http://www.peachparts.com/shopforum/diy-links-parts-category/146034-fast-navigation-do-yourself-links.html

JHZR2 · #6 05-14-2020, 09:31 AM

Quote:

Originally Posted by Diesel911

I changed the Sub Frame Bushing by lowing one side at a time. I remember having difficulty getting one of the bushings out. It took a lot of prying.

No doubt those things will be in there tight... but the level of deconstruction if the rear was going to determine if I would buy the questionable and cheap Meyle bushings, or try for a quest to find NOS MB or Lemfoerder.

That’s what I needed to hear, thanks!!

DeliveryValve · #7 05-15-2020, 03:07 PM

If I had to replace those bushings on a car I care about, I would go with Lemförder or OE Mercedes. Worry less and drive more!

Diesel911 · #8 05-15-2020, 09:08 PM

Quote:

Originally Posted by JHZR2

No doubt those things will be in there tight... but the level of deconstruction if the rear was going to determine if I would buy the questionable and cheap Meyle bushings, or try for a quest to find NOS MB or Lemfoerder.

That’s what I needed to hear, thanks!!

I don't remember what makers sub frame bushings I used.

Over 10 years ago I bought a front end kit and it was all URO parts. I used it and the URO upper control arms and Lower control arm bushings are still in use and OK.
I don't know why a front end kit came with rear trailing arm bushings and I changed them and the plastic sway bar links; I used them.
I am not recommending cheap parts just passing on my experience.

To get the sub-frame bushing out I used chisels as wedges to move them out till I could get a better pry bar on them.

JHZR2 · #9 05-15-2020, 09:39 PM

Quote:

Originally Posted by DeliveryValve

If I had to replace those bushings on a car I care about, I would go with Lemförder or OE Mercedes. Worry less and drive more!

This job is so easy to do, I mean way simpler than I ever thought. So the lack of quality rubber parts at this point concerns me less.

I suspect it’s a 30 minute job at this point. It took me longer to find the flanges and cut the rod to make the press, then it did to do the rest of the job.

I always prefer quality parts. This is the first time in forever that Ive bought meyle. Lemfoerder, MB boxed or bust. My cars are nice and in great shape, are not dds, so will truly last forever, so it’s fine by me to pay more. But these bushings are NLA and since the job is so easy it’s not really worth the time to fret over it IMO. If meyle fails in a year of extremely limited use I’ll change my story. And I don’t go searching out the cheaper stuff. But in this case I’m ok with it.