I hope this works out. I can't say if it will work or not since I have never thought of trying it.

Don't forget to weigh it to see if there is a significant difference.

Would the W123 calipers mount the same, or would they have to be upgraded to the gen.II calipers? Like the W126 up grade for the fronts on the W123.

Charlie

You know, even if they mount the same, the bleeder valve won't be the high spot in the calipers if they get mounted on the opposite side from where they were originally. Food for thought. Could it maybe be solved by swapping right for left? I have no idea. I'm not at all familiar with the rear end of a W126, and only barely familiar with the W123 variety.

I believe the first/second gen 126 arms are different no?

Oh, oh. Now I'm getting worried...

I dont have much to contribute to this thread, but If I get a chance Ill go and measure the ones I have behind my garage, I have both the steel and aluminium W126 trailing arms as well as the W123 trailing arms.

I suppose I could measure the first gen and second gen arms as well,

If i get a chance ill do it for the benifit of the board.

Well, still looks like we're going to try. The problem is though, since I don't have the "original type" on hand, if the shop takes everything off, including the subframe as we're replacing those rubber parts too, they'll be stuck with a car that can't be moved (with what they have available to them, anyway) for two weeks or so, so labor could add up if they needed to reassemble everything temporarily, and then take it all apart again later.

I'm convinced that the arms "will fit on..." I'm convinced that the brake calipers will be just fine, if they are reversed from side to side in the rear, to make up for the 180 degree off from original caliper mounting points... I think the sway bar will fit too, although it may be distorted slightly by "forcing" it to fit. (I sense that there is an ever so minor change in the length of the sway-bar mount points, and assume that there was a whole different sway bar used on cars that came with these aluminum arms. The latter is just speculation and "guestimating" by studying the arms, side by side, as best I could with them still on the car...

I don't know the terminology - aside from the main bushings, that the arms hinge on, what are the other three rubber/plastic bushings called? Spindle something or others? Anyway, although it would seem to be a good practice to change these out too, whilst rebuilding the rear suspension of these cars, why is it that it just doesn't seem like anyone bothers? I've heard that you need a special "push-pull press" to remove them, and that the same system is also used on some Volvos?

I don't know much about this stuff, but, "what's the story" with "whatever those parts are???"

Thanks so much. I'll document things as best I can.













Nick - Hazleton, PA

1971 280S
1983 300D Turbodiesel

Why don't you have the shop put the car up on a lift and compare the new ones to the old steel ones. It should only take a few measurements to confirm they will fit.

I know where there is a first gen SEC in the yard, are the rears AND the front aluminum/magnesium? sounds like a nice uprade for unsprung weight reduction too.

UPDATE...
 

Well, it's been over a month since I called my mechanic and had him tow the car in. As usual, the "going to be done in 3 days" turned into a month of excuses while I wait.

Now, instead of him physically trying, after this delay, he called someone he knows and they said that they will fit on, but the geometry will be "off..."

I am NOT SATISFIED, but I'm getting kind of used to this sort of nonsense.

New metal ones have been ordered from the West Coast. I'll list the aluminum ones in my eBay store.

What I would like to ask you all though is, if one was simply switching out both rear trailing arms, installing the three new subframe rubber parts and putting the car back together, what's a reasonable estimate of the time a shop SHOULD charge?

We're changing the brake discs/pads with new ones, but they have to come out anyway, as I see it. The new arms will get new main bushings (total of 4), new bearings and new parking brake pads.

PLEASE give me your input as to how much "sounds right" in hours for the labor to do just that???

Another question - I believe the OTHER rubber pieces on the original arms are called "spindle bearings..." The local shop, where this job started said that they recommend changing them. The machine shop they use insists that they can't do this, as it needs a special "push pull" press.

Are those 3 on each arm "other bushings" in fact called "spindles bushings?" How hard is it to change them? How important is it to change them???

Any help would be most appreciated.

I am SOOOOOOOOOOO disgusted with shops dragging my projects out. I ORDERED the correct parts. The used Mercedes place sent the wrong ones and insisted they'd fit. My towing companies that I've used lately are all a bunch of flakes. How the hell can the world function with so many incompetents out there???

I'm buying my own lift this summer. I must be living in a fantasy world or something, expecting shops to "do their job" without unreasonable delays.

I have a Porsche 928. It needed a timing belt job, as preventive maintainence. That, an x-pipe installed, a intake manifold refresh (hoses) and brake pads. It spent over 5 months between 2 shops, and came back to me with problems that have yet to be worked out.

Sorry to vent, but I would appreciate any additional advice, particulary an estimate to do the work on the Benz's trailing arms I described above.

Thanks so much for the previous advice/support. All the best!





Nick

Anyone, anyone???

Anybody care to estimate how long a competent shop should charge for removing and installing rear trailing arms and replacing subframe mounts?

lol

Anyway, I'd REALLY appreciate an estimate. One shop says "as much as half a day" and another says "at least 15 hours..." Both are the same hourly charge...

Hoping for input...

Bummed that the aluminum arms won't fit, I suppose, or at least I can't find anyone to try...










Nick

I'm trying to think how long it took me to do that job in the yard. I would say if things are not all rusted, and erring on the longer side of things. 1hr to take the whole sub-frame out. 0.25hr to take the diff and axles off. 0.25hr to take the trailing arms off the sub-frame. 1hr to replace all the bushings in the trailing arms (both). 0.25hr to re-install arms, 0.25 reinstall diff, and 1.5hrs to replace sub-frame, sub-frame bushes (if they have the right tool...I had to make one to get the bushings seated properly), and any other misc. stuff.

4.5hrs I would think for a shop. In the yard I think it took me about 2hrs, but I work fast.
Its a really easy job and I would do it again in a heart bead. In fact I will this summer, its my 240D's turn to get trailing arm bushes.

So, a minimum of 15 hours, or more, is DEFINITELY a really suspiscious estimate from a questionable mechanic?

Thank you so much for your input, BTW. We LOVE the car but feel a little stressed out with it off the road for so long...

a min of 15hrs is crazy!! What your paying for is the fact that they have no idea what they are doing on a MB. If it was someone who worked on these cars even now and then would know its an easy job.

where are you located?

I thought so. Thanks for confirming this. I'm in Hazleton, Pennsylvania, which is in the northeast part of the state. About 2 hours north of Philadelphia and 2 hours west of NYC via I80...

The local shop across the street suggested "maybe, a half day" but also felt that 15+ hours was unreasonable... Any advice? Thanks so much. I've wondered who to trust. : )





Nick - 1983 300D Turbodiesel