IRS Diff Inner Axle

[westaj]

It would be great if the forum could provide some info on the IRS Diff side axles.

When beneath my TR250, I was surprised to note that my near-side driving flange (next to the diff) has about 2 mm of axial free movement. The drive flange is fitted with a taper fit, key and nut to the diff side axle, so the axle is also moving 2 mm.

My questions are:

-is the side axle bearing inner a press fit onto the side axle?

-is there a locating shoulder on the axle for the bearing inner to butt up against?

-in the event of loss of press fit and no locating shoulder and the driving flange disconnected, is it possible to pull the drive flange out complete with inner axle? This would leave the bearing housing, oil seal and axle bearing all in place, with the bearing housing still bolted to the diff.

-or will the bearing inner only fit over the taper end and not the splined end, hence preventing full removal?

Any forum info on this topic would be appreciated.

Thanks

Jerry

[RogerH]

Hi Jerry,

not sure if I understand your problem fully. I had my tapered drive shafts out the other week to renew the seal (great fun).

 

If you remove the drive shaft from the diff - 4 x nuts/bolts - you should see a large nylok nut http://www.moss-europe.co.uk/Shop/ViewProducts.aspx?PlateIndexID=2501

 

it may be that the nut has come undone - they certainly can do. You may be lucky in tightening this up will solve your problem. If it does then fit a NEW nut - never reuse nylok nuts.

 

If the seal body is loose on the taper then consider replacing the seal at the same time.

 

The torque load for these nuts is high plus a bit.

 

Give it a go and report back

 

Roger

[BlueTR3A-5EKT]

Yes the axial movement is possible as the bearing of the side shaft does not fully fill the hole depth in the diff casing - but I would not have expected 2 mm (80 thou in old money). The hole is deeper than the bearing width plus the raised edge of the bearing retainer plate that supports the bearing. Is the plate that holds the seal fitted the right way round to retain the bearing in the recess of the diff casing? Has someone fitted a gasket between the flange and the diff case? Should be metal to metal with a gob of sealant.

 

There is a shoulder on the inner end of the drive shaft to stop the shaft pulling right out the bearing. Movement might be shaft through the bearing instead of bearing in Diff.

 

To my mind the diff casing or the bearing outer surface may be worn. If it is sloppy the shaft will be able to shuttle, which it should not do in service. Are the splines of the drive shafts seized or very tight?

 

Peter W

 

NB There are Left and right drive shafts which are different lengths. The outer key and keyway got bigger on later cars, so watch out for that little gem, as the flange has to match.

Edited September 17, 2014 by BlueTR3A-5EKT

[westaj]

Roger and Peter W , thank you for your helpful replies.

 

I suspect the main drive shaft (to the wheel) splines are tight, and that has caused some additionasl loading at the diff side axle bearing.

 

I get an occasional light clonk coming out of a roundabout. This could be linked to the diff side-axle-shaft free play which I have observed.

 

When at Goodwood Revival last Sunday, I got talking the the Sales guy at SC Parts (Gatwick). To cut a long story short he sold me a couple of new cv shafts with hubs and these should arrive shortly.

 

There will be a delay before I can fit these, but I will hopefully be able to examine and replace the side axle diff beatring when fitting the new SC shafts.

 

I will post more data when I have managed to get everything apart.

 

Thanks again,

 

Jerry

[RogerH]

Hi Jerry,

I think you should have found the problem first.

 

The standard drive shafts are easy to check to see if they are sticking or seized.

 

The CV mod has a good following on here but I am still old school and prefer quality standard shafts.

 

When fitting the new CV/hubs be careful when tightening the 6 hub attachment nuts. If the studs are sitting in a corroded hub hole they may pull out.

 

When I was at Goodwood on the Saturday I bought a pint and a wine = £10. I managed to steer clear of the shiny stuff.

 

Roger

[RogerH]

I was chatting to Jerry last night at a group meeting and realised that the thing that is moving back and forth could be the dirt cover for the seal.

 

This is a flanged disc that is welded to the bearing carrier and helps keep muck away from the seal area.

 

I had exactly this problem on my diff a few years ago.

 

What will be revealed upon inspection !!!!!!!

 

Roger

Edited September 19, 2014 by RogerH