Suspension Repair Plan Query w123 - PeachParts Mercedes-Benz Forum

Bengoshi2000 · #1 09-01-2011, 06:55 PM

So I've got tentative arrangements made to rent a klann spring compressor to replace the guide rod mounts, guide rod bushings in the LCA, and the LCA bushings. I'm going to replace the rubber cups on either end of each spring while I'm in there. LBJs and UCAs were replaced back in March. Am I missing anything I should do while the springs are out?

The $64 question is whether I should bite the bullet and replace the rubber in the rear while I have the spring compressor. And if so, what should I replace?

Thanks in advance for your replies.

Yak · #2 09-01-2011, 07:22 PM

There are a few threads, parts lists, etc on exactly this. Most recent is, IIRC, the Don's 240 thread. Maybe PM him for info.

Compressor is not needed for rear springs. You can undo the shocks, raise the car and the springs fall out (grossly simplified but basically true). Rubber on the rear is more associated with the sub-frame. Different set of tools/techniques needed.

"Rubber cups on either end of each spring"? Do you mean the spring pads?

I also cleaned, POR-15'd and painted (carefully to avoid the mounting surfaces) the LCA.

Diesel911 · #3 09-01-2011, 09:58 PM

Before I read that the Rear Springs did not need to be compressed I had already done it.

The Rear Springs do not have as much tension as the Fronts do and they were compressed safely with the regular strut type Spring Compressors.
The only issue I had was on the set of compressors I have one end has 2 claws.
That made it difficult to space them opposite each other.
Like I said that was before I knew better.

The Rubber Trailing Arm Bushings do not as frequently cause issues as the Fronts do.

I exchanged my cracked Trailing Arm for another Used one and did not replace the Rubber Bushings over 3 years ago with no issues at all.

I also replaced the LCAs and had a bad time with one of the Eccentric Bolts that had rusted to the Aluminum Sleeve of the LCAs and did not want to come out.

winmutt · #4 09-02-2011, 10:04 AM

Use the W126 LCA bearings.

The rear springs do not "fall out" on all W123's but as stated the free rental compressor from local autozoo will do the job.

Bengoshi2000 · #5 09-02-2011, 07:40 PM

Quote:

Originally Posted by winmutt

Use the W126 LCA bearings.

Are they better?

Yak · #6 09-02-2011, 08:16 PM

The W126 bearings are a 3-piece instead of the two piece.

Compare http://catalog.peachparts.com/item.wws?sku=W0133-1624590&itempk=104123&mfr=Lemfoerder&weight=1.30
to
http://catalog.peachparts.com/ShopByVehicle.epc?q=1984-Mercedes--Benz-300d-Suspension&yearid=1984%40%401984&makeid=63%40%40MERCEDES+BENZ%40%40X&modelid=6192%3AED%7C10000135%3AMBC%7C1504%40%40300D&catid=241464%40%40Suspension&subcatid=241505@@Control+Arm+Bushing+Kit&mode=PD

Easier to install. Also listed in the FSM as an "upgrade" for using 15" wheels or police suspension. I don't know if there'd be any appreciable distinction in handling or comfort from one or the other types.

If in doubt about fitment or utility, call/email whunter or phil.

TheDon · #7 09-02-2011, 09:13 PM

the w123 part is 3 pieces as well. I think the w126 version doesn't involve flaring the ends

Yak · #8 09-03-2011, 02:14 PM

Quote:

Originally Posted by TheDon

the w123 part is 3 pieces as well. I think the w126 version doesn't involve flaring the ends

True. I wasn't counting the metal tube as a "piece" even though it clearly is.

I remembered the difficulty in getting the two rubber parts fully compressed into the LCA for the W123 style. The insert for the W126 style would have been easier.

I didn't have trouble with the flaring, but I have read where other people have.

TheDon · #9 09-03-2011, 02:21 PM

I should have ordered the w126 version. I didn't put my bushings in. I do have them if the OP wants to buy them

Bengoshi2000 · #10 09-03-2011, 10:31 PM

Quote:

Originally Posted by Yak

The W126 bearings are a 3-piece instead of the two piece.

Easier to install. Also listed in the FSM as an "upgrade" for using 15" wheels or police suspension. .

An easier install sounds good to me. Will the w126 bearing be compatible with the existing eccentric bolt?

dieseldan44 · #11 09-03-2011, 11:44 PM

Having done both projects - they are entirely different and do not share the same tools and techniques (as others have stated).

The spring compressor makes the rear job a bit faster and easier, especially for re-install. But, as also stated the autozone compressor can be used on the rears.

IMHO, to do the rear 'right' really deserves taking the whole subframe off, POR-15ing it if in a northern climate, and replacing all of the bushings - so much easier with the subframe/trailing arms out of the car. charmalu and Army have posted a lot on this (and i have followed their advice/writeups).

Yak · #12 09-04-2011, 12:05 AM

Quote:

Originally Posted by Bengoshi2000

An easier install sounds good to me. Will the w126 bearing be compatible with the existing eccentric bolt?

I put the W123 style in and had issues with compressing the larger rubber firmly into the LCAs. Since the 126's are listed as compatible with no other changes, I believe there are no issues with reusing the eccentric bolt. Phil or Whunter (contact info at "buy parts") can set you straight and correct me if I'm wrong.

When fitting new rubber into the suspension, you should make sure you have the correct lube on hand. Lube the parts that you should, not the ones you shouldn't. Putting the rubber in the freezer overnight helps, too. It shrinks it slightly and makes it harder so you're fighting the natural compression less.

winmutt · #13 09-04-2011, 12:48 AM

Eccentric bolt is the same. The W123 is a 2 piece bushign with a tube, W126 is 3 piece bushing. W126 is recommended for W123 on harsh roads of 15" wheels.

Bengoshi2000 · #14 09-04-2011, 08:24 AM

After reading a bit on the rear suspension, I'm going to hold off on that for now. Rear tires are wearing perfectly and I don't have any major rattles and no shimmy/shakin' goin' on. Besides, I have a line on 2.88 diffy and I only want to drop the subframe once... might as well do all of that at one time.

As far as lube goes is thee any particular brand that is preferred?

Stretch · #15 09-04-2011, 08:34 AM

Quote:

Originally Posted by Bengoshi2000

After reading a bit on the rear suspension, I'm going to hold off on that for now. Rear tires are wearing perfectly and I don't have any major rattles and no shimmy/shakin' goin' on. Besides, I have a line on 2.88 diffy and I only want to drop the subframe once... might as well do all of that at one time.

As far as lube goes is thee any particular brand that is preferred?

KY jelly is often considered to be the best thing to use as it is water based - oil based lubricants are generally not good for rubber parts.

Over here I found that a company called Kroon Oil make a lubricant similar to this for the food industry. I got some tiny packets on proof but the retail cost is pretty much out of the average man's reach as you need to buy huge industrial quantities.