W123 A How to, replacing rear axles.

[dmorrison]

W123 replacing rear axles


My son’s 1985 300D’s rear axle was making noise. The outer boots, inner clamp, was loose and I’m sure some or all of the oil was gone. He started to get a clicking noise upon de-acceleration so I knew it was time for a new axle. I called and got New axles from Advanced Auto. SKU # 20870644. They shipped them directly to the house for $92.97 each. I also purchased new differential to axle seals just in case the installed ones were worn. The seals were fine once I disassembled the differential so I chose not to replace them.
The axles are made in China so we shall see how they perform.

One word of caution. The wheel hub to axle bolt spacer that was provided was longer than the one on the car. Measure these carefully and IF the axles are original to the car or have been there a long time, reuse the spacer tube that you remove, otherwise the axle will not completely seat into the hub. I also had the bolt provided break while installing it. So I would reuse what Mercedes provided.


Picture #1
Place chocks under the rear of the FRONT tires since you will be jacking up the rear tires.

Picture #2
Jack the car up using the differential. I have a long body jack and it is easy to raise the car from the rear bumper area.

Picture #3
As you can see I have placed the jack stands under the sub frame bushing area. I find this to be a safe and secure place for the stands. After you have settled the car onto the stands, give the car a good shake and make sure the stands have not changed position under the car. If they have in anyway moved, reposition the jacks stands.

Picture #4
Since you will be opening the rear of the differential, either pressure wash it or use a degreaser and a brush as shown. I completely pressure washed the car back in October when we got it. So the car was pretty clean and only required a brushing.

Picture #5
Remove the fill plug in the differential (14MM Allen socket). Always a good idea to remove the fill plug first, instead of the drain plug. You would hate to find out the fill plug is stuck after draining the oil. I am going to reuse the installed synthetic oil since we installed it last November. We filtered it and reused it.


Dave