today I could finish the disassembly of the IRS of my '72 S3. I now have the final drive unit on the dolly and wonder, how to proceed from here?
As a little background, I bought the car in non running condition. Thus, I know nothing about how the differential behaved when the car was driven last. Further, I have no idea when the car was moving on it’s own the last time.
I would appreciate any input about what to check and what to replace anyway. My current plan is as follows:
Here is my opinion, since I just did it. Take the inspection cover off after draining. Paint the gears and make sure all markings within spec. Check pinion / ring gear for wear, backlash, etc. Then pull apart making sure you keep track of what shim goes where and change all the bearings, seals, etc. Reassembly is the reverse of pulling it apart . I
Hi Manfred…my advice would be to take it to a diff rebuilder and have them do it…its a lot of work to install this unit and ideally you want to install one that you know has been refurbished correctly…im sure you have enough other jobs to do…Steve
Hi Manfred. Ordinarily replacing bearings and seals on an old differential is relatively straightforward, as you just reuse the old shims with the new bearings. However the Ser III diff uses a collapsible spacer instead of shims to set preload on the pinion shaft. This makes it faster and easier for a specialist to assemble but can make it more difficult for the amateur. Watch this video from Paul Cangalosi as he’s dealing with this issue on your differential https://www.youtube.com/watch?v=OurJHaiy6kI&t=2042s
Unless you’ve got some experience in doing diffs, or have somebody who has help you, and have access to some special tools, I’d recommend Steve’s opinion and have it done. In N.A. most 4 wheel drive repair shops have good people on rebuilding Dana 44 diffs (yours may be manufactured by Thornton, or Salisbury, but it’s a 44 at heart.) as these diffs are ubiquitous on US cars and trucks. Don’t know what’s available in Germany.
PS you’ll probably want to put new clutches in the limited slip, and actually replace all the bearings, some of which may be damaged by removal.
Hello Manfred,
Your differential will be a Salisbury.
The correct bearings for the Output Shafts are no longer available. The originals was a double row, angular contact bearing that had a split centre race that when the securing nut was tightened, the correct, built in pre-load is applied. The replacement for this bearing is 2mm narrower and therefore requires a 2mm spacer for the inner and outer raceway of the bearing. The inner race of this bearing is one piece and no pre-load is possible.
If you can find a set of Output Shafts and Bearing Housings from a S2 or S3 XJ6, or from an XJS Salisbury differential (not Dana) , swap the originals with these, as they use opposing Taper Roller Bearing. The bearings for this system are available and is a better system (in the absence of the correct, original design bearing) generally.
