The other day as my wife was turning into a parking space a guy in a 300SE backs up and parks his right rear corner into the driver's side rear wheel. It bent the upper and front suspension links and the swaybar pretty badly. The left rear wheel is canted inward at about a 10-12 deg. angle and toed-in almost the same. I was planning to replace all the suspension links, all the suspension, subframe and differential rubber mounts, shocks, rear flex-disk, transmission and engine mounts anyway sometime in the near future, so I guess now is the time. For the suspension repair, including dropping the subframe and some minor dent repair I'm hoping to get about $1500 from his insurance co. I've got a few questions on R&R'ing the subframe. First, do I definitely need the spring compressor before I remove the subframe, or can I loosen and lower it on a jack (or two), decompressing the springs in the process, or is there the danger of the springs flying out? What if I used a couple of loops of chain to keep them with the lower control arm? I'm just trying to avoid having to rent the compressor twice. Btw, I'm assuming the upper spring seat is part of the chassis, not the subframe. Is this right? Next, I figure that it's probably easier to disconnect the driveshaft and drop the subframe with everything attached and then just rebuild it off the car. Is this the best way to go? Can anyone offer any hints or tips on doing this job? Any stumbling blocks I'm likely to run into or things I should watch out for?

Thanks,

Gary

If you have the jacks and stands, the rear coils can be removed without a spring compressor, you just have to be careful when lowering the lower control arm. The upper spring seat is part of the rear unibody, not the subframe. You will need to uncouple the flex disc, ABS and remove the calipers from the hubs to drop the subframe.

In addition to MTI valuable advice I can tell you what difficulties I encountered when we did that job on my 300TE. In order to disconnect the driveshaft you'l have to loosen the big nut at the support bearing. For this you'll need unusual large wrenches, 41mm and 36mm, I believe. I bought cheaper and slightly smaller standard size wrenches from the local hardware store and ground them to the correct metric size. The rear flex disc was bonded onto the driveshaft and the diff - the air chisel was great to separate them. Watch out for the fuel line, disconnect it before lowering the subframe, at least that was important on my 300TE - I do not know for sure about the sedan. Links are easy whith the subframe out of the car. Check for the correct orientation of the bolts which is not intuitive but may matter in the future in case you want to tighten loosen them with the subframe mounted. It is easier to tighten all links with the subframe still out of the car. Just make sure the axles are horizontal relative to the subframe in order to simulate load. Control arm bushings were the most difficult. I finally had to cut the outer bolt of the control arm and also the control arm itself in order to remove it. I bought new control arms (about 60$ each). I also bought the Baum tool to remove/install the rear ball joint. The subframe mounts were were hard to get out - we finally burnt them. A good puller may have worked too. The diff mounts need proper orientation vertically. We pressed the old ones out by pressing the new ones in using a cheap harbour freight ball joint press. Also this may be the moment to do some rust prevention (POR15?) on the subframe.
Good luck! Bruno

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1992 300TE 160 kmiles

How does burning make it easier to remove them? I thought they had metal outer shells that were pressed into the subframe.

Any idea if AutoZone has a loaner puller that would work well?

Are there any particular areas where rust hides in the subframe that isn't obvious?

Gary

I f remember correctly the outher shell is thin metal and easily bent when the rubber is gone. Anyway, the bushings came out after a few light taps with the hammer after burning. But burning made a big mess - all that rubber became a powder that distributes easily throughout the place!

I do not know, you could bring the new bushing and try all the pullers they have and see whether one potentially could work?

No, not really. I my case it was the welding seams that were a bit rusty. I was in a rush when I did the job and did no rust prevention.

Bruno

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1992 300TE 160 kmiles

I have two questions here... does the sedan also have the 41mm and 36mm bolts, and do they require a wrench or will a socket work? doityourself.com has the 41mm socket for $11.29 and the 36mm for $9.29. If I can do the job with these and a 3/4" breaker bar this doesn't add much to the tab.

I am leaning toward dropping the whole subframe since I will replace all the links, all the bushings (may as well do diff bushings also), and will install Sportline swaybar and springs. Any advice is appreciated while I wait on the remaining few parts. If I drop the whole thing I guess I need a new rear flex disc kit?

(1) Sedans and wagons are the same: they both have the 41mm and 46mm nut (36 and 41mm was the wrong size, sorry). You'll need wrenches, not sockets (eg http://www.samstagsales.com/mercedes.htm#drive sells them, but they are too pricey IMO).
There is a pdf manual that you could download (http://mb.braingears.com/124_DISC2/Program/universal_shaft.htm file: 41.050pdf, p. 22ff - it is a 23 MB file, youl'll need broadband access.)
(2) Yes, I would include a new rear flexdisc - I had to destroy the one that was one my car. Nothing else I can think of at the moment, maybe parking brake cables.
Good luck, Bruno

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1992 300TE 160 kmiles

Will a combination wrench work, or will I need a thin 'spanner' type? For what Sam Stag wants for those two, I can get a set of 10 jumbo combination wrenches (34, 36, 38, 41, 42, 44, 45, 46, 48 and 50 MM). Might come in handy if I ever need to work on some German earth moving equipment.

Between a new flex disc and new wrenches, leaving the subframe in the car is starting to look more attractive. I just hate working in tight spaces, particularly if what I am working on is above me on jack stands.

Damaged 1986 300E
1. Driver's side rear wheel
2. Bent upper and front suspension links
3. Bent swaybar
4. Left rear wheel is canted inward at about a 10-12 deg. angle and toed-in almost the same.

With this type of damage, the insurance would be lucky to get it taken care of for $1,500. Even if you fix the things you plan on changing, you'll never be sure if the the car is straight and structurally stable. My family is worth more than a few measly thousand of dollars. If I were you (I also drive a 86 300E), I'd have them total the car for $3,000-4,000 and just get another one. I may be overreacting, but from your description of the damage, the suspension is "WACKED".

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JR
1986 Gold 300E 4Dr automatic

The 41mm goes to the driveshaft and the 46mm to the nut. You'll need them both at the same time. They do not need to be unusually thin. Combination wrenches should work unless it is a 41/46mm combination (I do not know what common combinations are). By the way, other people on the forum succesfully used large crescent wrenches or pliers (For example I remember Larry Bible posting about this). Also the flex disc might not be absloutely mandatory. You can decide after you see how the old one came out.
I thought it was worth taking the rear subframe out, especially if you intend to change subframe and differential bushings as well. If you skip those you could just drop the subframe by 3 inches on each side at a time in order to get better access to the links.
Bruno

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1992 300TE 160 kmiles

I don't mind the flex disc, it is probably a replace me now or next year deal. I just like to hold down the number of one shot tools I accumulate. I was a lot more reckless 20 years ago, but I changed out the struts on my 914 with a pipe wrench. (missed the first Miami Grand Prix doing it, too; I could hear the engines across the bay)

Here are the combo wrenches I saw.

If I can get the nut loose with crescent wrenches, I guess I am back to dropping the subframe. Safety and comfort vs a little more work.

I see, a combo wrench is a combination of open and box ends...
Good luck, Bruno

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1992 300TE 160 kmiles