ek axles into fc diff

[Gary C]

Rear wheel bearings are slightly wider for fb onwards than up to fc and are shown as different part numbers.

What bearings have others used when fitting EK axe to FC housing?
I also noticed there is a about 2mm difference in face of axles EK being wider.

Thanks, Gary.

[ardiesse]

Gary,

Good question.  At the very least, you'd have to use FC rear wheel bearings when fitting an EK half-shaft to an FC rear axle housing.

Who's got a master parts catalogue?  Do FE-FC and FB-EK axle shaft assemblies have different part numbers?

Rob

[mcl1959]

Yes, FE FC axle is 7406280 and FB EK is 7419543
It is possible the difference is just the bearing land length on the shaft though.

Ken

[Gary C]

Yes that seems right Ken I fitted the narrow sealed fc bearing to a ek axle today and fitted to fc housing no problems also noticed other side is already fb/ek axle.

The Fb onwards bearing has the o ring seal and wider bearing.


As mentioned the flange face that the drum sits against is also 2mm wider.

[ardiesse]

Now I'm just going to confuse things.

I have a pair each of FC rear axles and FB/EK rear axles.  The FC axles have 7413279 forged onto the hub, the FB/EK axles carry no part numbers.

In all respects (overall length, flange thickness, flange-to-bearing-shoulder distance, flange-to-bearing-retaining-ring distance, bearing inside diameter) they are identical.  The only difference I can find is the smaller diameter machined surface where the rear axle oil seal bears on the axle shaft.  In the FB/EK rear axles, it's maybe 1/2" wide.  In the 7413279 FC axles, it's maybe 7/8" wide.  The inner races of both series rear wheel bearings appear to first approximation to be the same width.

It seems to me that you can run FE-FC axles in an FB/EK rear axle housing, as long as you change the rear wheel bearings over to FB/EK.  If you fit FB/EK rear axles to an FC rear axle housing (along with the FC rear wheel bearings) you run the risk of rear axle oil leaks, as the FC rear axle oil seal lip has nothing to bear on.

Just consulted page 4-2 of the FE/FC and EK shop manuals respectively.

Beware! The EK has no rear axle oil seal.  That job is performed by a seal assembly on the outside of the bearing assembly.  FE and FC do have the rear axle oil seal, inboard of the rear wheel bearing, and that's why the seal bearing surface on the FC rear axles is a lot wider than on the FB/EK rear axles.

Interesting to note that the rear axle oil seal was re-instated from EJ onwards, and the rear wheel bearings were lubricated by grease.

Rob

[Gary C]

Thing is the fc bearing is sealed,so in effect the fc has a seal in the housing and sealed bearing.

The fb has a o ring seal in  bearing also  a o ring seal on the oil deflector that sits against outside of bearing.

I havent had any leaks in left side with ek axle with fc bearing (just didnt know I had that combination till today) in 3 seasons racing with overfilled diff so yes Iam confused given axle flange facing also 2mm thicker.( on the 2 axles i have any way, main reason I changed to ek being I fitted 75 mm studs and the wider flange grips them better than fc.)
Axles were from ek auto not that that should make any difference.

Anyway all good and will let you know if they leak after 1st race  meeting of the year this Sunday.