I have spent several hours reading through all the suspension-related posts and have learned a lot from them, thanks. I think we could really use a good thread on the best procedure for a complete W123 rear suspension rebuild (without lowering ride height). Richard Easly documented a procedure for the W126, but there are no photos and the procedure is just for the subframe bushings. I just got done changing all the calipers to the newer ATE ones. I got tired of having issues with the Bendix junk. Also got new Balo rotors and Pagid pads, changed the brake fluid, and replaced all the brake hoses.

I am planning on doing the following maintenance work and documenting everything with photos and notes as I go for everyone needing these things done.....

1. Replace subframe bushings, possibly bolts too depending on condition.

2. Replace trailing arm bushings, bolts if necessary. Which one should I use, there's a repair size and a regular size. Also which vendor has the best rubber?

3. Straighten the spider plates (one was bent), removing rust - treating with POR-15 and chip guard.

4. I have a broken left (generic it turns out) rear shock from a bogus mechanic's work when I was living in Chicago. (That jerk also broke my injection pump rack damper mount by turning the bolt too far, put in a non-MB washer pump screwed to my inner fender, and hung my exhaust in the wrong place. I sent the guy packing! He was so incompetent he should be glad I didn't sue him...BTW - Import and Domestic in Evanston, IL ---avoid these guys...) Manfred (the Man!!) Pfeiffer at H&M ******** in Westchester, IL (German born and MB-factory trained expert, now retired, his company, H&M was passed on to Manfred's top mechanic...my Diesel misses you Manfred!) put everything back right again, except for the shocks which we did not know then were generic. I am now replacing both rear shocks with new Bilstein HD's.

5. Removing rear springs, rustproofing, repainting, replacing (the old vaporized) rubber coil top shim pads with the 19mm ones. That oughta stop the knock knock jokes this car keeps repeating...

6. Rust removal and treatment of all suspension subframe and trailing arm components. Por-15 paint, then Transtar Tex coat Chip Guard.

7a. Replace differential mount.

7b. Check differential seals and replace leaking ones. Am I crazy to try this? Anybody done it?

8. Replace driveshaft flex discs and mount/bearings. Again is this a *****? No procedure found other than in service manual.

9. Rustproof exhaust system. and re-hang with new rubber.

10. Change trans shifter bushings (I hear it's easy and I'll be under there anyway)

11. Change the fuel tank strainer. Yucky black stuff...ewwww..thank God for gloves.

12. Replace rear sway bar connecting rod ends and bushings. What's the best vendor for these?

13. Replace big rubber snubber stops near sway bar ends. Again who's the best vendor?

14. Lots of rust removal, welding and reinforcing if necessary. Followed by rustproofing with POR-15, and acid-etch primer. Then coat everything with Transtar Tex Coat Chip guard...

I am looking for other suggestions on things I should do while I'm under there....and especially photos or procedures of how others have done this if they exist...believe me I've looked.

You certainly have done your homework.

It appears, from the list, that you may be removing the differential from the subframe to reseal it. In any case, you have removed the drive shafts to get the trailing arms out.

So, the only thing I would add is to consider replacing the rubber boots on the drive shafts before they fail.

There are shops that can do this for about $100.00 each, or you can consider lifetime replacements from AutoZone and the like. However, the success rate with these "rebuilt" axles has been spotty.

Some members have replaced these boots themselves, but, it's a real PITA without the proper press.

My boots are actually in very good shape, no cuts at all. I might treat the rubber while I'm under there. Manfred (the man!) at H&M replaced one axle for me about 4 years ago when it failed due to a bad boot. Do I need to remove the axles from the hubs to change the seal at the driveshaft or can I just lower the differential with the axles attached and do it. The manual is pretty sketchy/few photos.

Should I think about changing the rear transmission mount or is that a real PITA?

I've never messed with the driveshaft either before. Is the flexdisc and bearing stuff worth the hassle? My flexdiscs actually look and feel pretty solid for being 20 years old but maybe they've petrified... :

__________________
Theo

1985 300D turbo 235K miles, Delvac 1, mostly B20 BioDiesel

klakka klakka klakka klakka...Arf arf arf arf...
How does that dog always know when Theo's home??!

You had mentioned that you are going to do trailing arm bushings.

I presume that you will remove the trailing arm from the vehicle to get them out, or can you do it underneath? I recently abandoned the idea of doing trailing arm bushings on the SDL due to the difficulty of trying to get them out while working on your back. I was not about to remove the arm from the vehicle.

If you remove the trailing arm, the axles must come out first.

Most of the notes I have read refer to using a press and/or liberal amounts of PB-Blaster, all-thread rod, washers, and nuts to press the bushings out. One guy spoke about removing them, but I am not in favor of disturbing the axles, bearings, and hubs. If one speck of dirt gets in the hub bearings or differential gears you can have major problems.

My mechanic pointed out when I changed the brake calipers that the diff looked like it was leaking a little, but also told me that I should leave the diff alone unless I am going to do a complete rebuild, and that changing the seals is a *****. I did not get any feedback on changing diff seals to the contrary, and can find no posts of anyone DIYing it. He said the leak looks minor and slow, and to just check the fluid every couple of months and refill it. If I do win the lottery and decide to rebuild the diff after all, I will remove it and take it to him to do a complete rebuild for me on a proper bench with dial indicators, micrometers, etc, as called for in the Mercedes shop manual. I have none of those. I don't think it would cost more than 3-4 hours of labor to do it, which would be under $500.

So I am going to try and locate the proper Mercedes tool for pressing out/in the bushings if I cannot do it with the all-thread rod or a more generic press. That means leaving the axles in the hubs, just disconnecting it from the subframe, lowering it, and pressing in/out new ones.

At least that is the plan unless I get some more/better feedback from those who have gone before...

__________________
Theo

1985 300D turbo 235K miles, Delvac 1, mostly B20 BioDiesel

klakka klakka klakka klakka...Arf arf arf arf...
How does that dog always know when Theo's home??!

Definitely repost on how you make out with those bushings. I haven't changed these and might consider it, provided I don't need to remove the arm from the vehicle.