S3 diff dismantling tools

[lowact]

Any advice?
Changing my FD from 3.54 to 3.07 with new oil seals all round.
According to the workshop manual the pinion "zero" mounting distance (C) is "4.312 in. (108.52 mm)". Checking this imperial/metric conversion, it is wrong, should be 109.52 mm!

My existing pinion setting is +9 (thou), so existing pinion mounting distance is 4.321 in. = 109.75 mm.

New pinion (Quaife via SNGB) mounting distance is 109.22 mm therefore, relative to the existing, it needs to be mounted 0.53 mm closer to the centre of the ring gear. To do this by the book I would remove the bearing and add shims underneath, where it presses into the casing.

To remove the bearing cup from the casing requires special tools. And if I disturb/renew the brg, any relative adjustment (as above) would be unreliable...

Alternatively I could retain (not disturb) the existing bearing (it looks ok) and just add required extra shims on top of it, i.e. between it and the head of the pinion.

Same difference?
Is there ways to remove the pinion brgs without the special tools?

[angelw]

Hello Colin,
Both Pinion Bears should be an interference fit on the their respective journals, but often the outer bearings is a close running fit. This is OK as the two bearing assembly is locked up solid via the collapsible spacer and the clamping force applied by the Companion Flange nut. Therefore, the outer bearing is reasonably easy to deal with, leaving the inner bearing firmly on the shaft.

The potential to damage the inner bearing assembly is diminished to practically zero by working on the Bearing Cup and not the Bearing Cone that's on the shaft. The Cup has enough lip exposed, looking from the outer bearing end of the diff housing, to be able to use a steel disc turned to an OD slightly smaller than the bore of the diff housing where the cup is supported and then push the cup out from the outer bearing end of the diff, or pull it out from the differ cover plate end. The pull method requires a centre hole in the disc and a solid flat bar that will bridge the diff cover opening. The flat bar also requires a hole drilled through to accommodate a length of Threaded Rod to pass through it and the steel disc. Two nuts are then used to pull the steel disc and the Bearing Cup towards the flat bar.

Best regards,

Bill

[lowact]

Thanks Bill. Now I'm thinking all new bearings probably the wisest approach.

[mgcjag]

Hi Colin....if your doing o/p shaft bearings note that the original double row collapsable ball bearing type are no longer available and a poor substitute is offered by the usualls with shim spacers...but your unable to set the preload correct....worth considering a swap to the later xj6/xjs type o/p shafts that use taper roller bearings...lots of info here if you search and Bill has posted quite a bit about it.....Steve