W123 Rear axle replacement questions
 

Howdy, getting ready to replace the rear axles on my 82 240D. Two questions:

1. New springy clip inside the differential? Or OK to re-use the old one? If new, how/where do I find one? Is it a specific Mercedes part or a common standard size clip?

2. What kind of oil/grease do I put back into the differential?

Thanks as always!

Jim

Before draining out the old Differential Oil be sure you can remove the Fill Plug. They can be extremely stuck.

I have only ever read of people reusing the "C" Clips and they are a Mercedes Item. However, I suppose it is not impossible for them to be damaged which means they need to be inspected.

I used regular differential Oil from Autzone.

Note the original spacers need to be saved but if there is spacers they may or may not give the proper fit with replacement axles.

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

I am looking in the Manual and it has to renew the locking rings after one use. Use your own best judgment on that.

You should also read up on the end bolt and spring washer that go on the hub end of the axle. There is different sized bolts that have to match your replacement axle and it has to renew the clamping disc (washer) after a one time use.

2x on the spacers. There is a FSM spec on end play of axles. I think its around 1/16". Too little play and the clip wont go back on, too much and you will have a rear axle clunk from time to time.
Generally the old spacers can be reused. They are also available at the dealer if new ones are needed.

Thanks for your help as always! Doing this job next week....will let y'all know how it goes.

There's a great pictorial on here from the days of yore where a pilot explains step by step how to replace the axles.

Really one of the early gems of the online automotive community. It was the reason I was able to drive my Benzes for as long as I could.

Another member recently pointed out that removing the differential mount gives more room to get the axles out if needed.

If the axles seem too long to get them out, I'd try it with the diff mount removed so that the diff housing can be raised higher.

Good luck!!!

Part of the above is not correct. From the Manual "There should be no noticeable end play: the locking ring should just barely turn in the groove."

The differential mount has to come off anyway.

I don't have any idea what those spacer look like since I haven't done the job yet. I guess they look like big washers....wonder if it's possible to fabricate one if necessary. I have read where people have had to grind them down but nobody I've read here has posted anything about having to add them.

The spacers come in different thicknesses.

Both sides of the surface have to be machined parallel and the ID needs to be a specific size. I have no idea as to what hardness they are.

Spacers are not always present.

I wouldn't stress too much over it. I bought a 123 years ago that needed spacers and didn't have them. There was an annoying clunk sometimes from the rear when the axle moved. At the time I didn't know what was causing the clunk but after about a year I decided to investigate. I could replicate the clunk by grabbing the half shaft and moving it back and forth with the sound coming from the differential.
I removed the diff cover, pushed the axle all the way into the diff and measured the distance between the axle retaining clip and the splined housing. Ordered ones to stack to the thickness measured and it was done.
I contemplated fabrication, but the shims were cheap from the dealer. The only downside is that for a daily driver the diff cover has to come off to measure, and then again to install the shims.

What did you use to measure the gap?

feeler gauge. I wish I could remember where I saw the tolerance for this. You are correct that it's less than 1/16th. Its probably half that or less, but you don't want to have the axle retaining clip under pressure, so play is preferable to having it too tight. I am putting flex discs in my 84 this morning and it has original axles. There is play on one of them, but its not much and not enough to make noise.

OK thanks, I think I get it now. The spacers are beside the spring clip and the only downside to having play is an occasional clunk, not a complete failure. Is that right?

I thought they were outside the diff housing and play could lead to the whole rig coming apart. I can live with a clunk until I get shims, and then install later. I'm in NZ and parts take two weeks from Germany.