Front Axle End Float

[geodon]

I'm @ the stage of refurbishing hubs & brakes.

Rears were straight foward enough but while removing the split pin from the castellated nut securing the front axle to the hub I noticed there was up to 2-3mm of end float.

At 1st I thought the bearings were sloppy but they were tight.

It was the same on both sides.

The short axle is out & the UJ was tight & the splines seemed OK.

Is this normal?

It has FW hubs.

[newhue]

If you are talking about the axel sliding in and out a littler then yes that's normal. The movement allows for steering and suspension articulation to all work at once.

[JDNSW]

Normal except, I think on 80" Series 1. Movement inwards is limited by the bearing at the end of the axle housing, and outwards actually by the drive flange, which presumably is not installed yet. The free play allows for tolerance in lining up the centre of the U-joint and the swivel axis.

John

[geodon]

Yes John & newhew, I agree. Except it's a 2A & the drive flange was/is still attached! I can actually grab the big nut outside the drive flange & get ~2-3mm of in-out movement. Both sides. The hub stays put.

Seeing the workshop manual is so anal about end float in the rear ( using a dial indicator, no less!) I'm non-plussed.

There's alot going on up front compared to the rear so I'd expect a bit more leeway.

I was ordering some gear from a LR specialist this morning & his mechanic told me that's pretty normal!

[Warb]

Seeing the workshop manual is so anal about end float in the rear ( using a dial indicator, no less!) I'm non-plussed.

The end float you mention (measured with a dial gauge) is the hub, not the drive shaft. It is float on the wheel bearings, and can be set without the drive axle and flange in place - adjustment is via the inner of the large pair of "special nuts" on each stub axle, and is then locked by bending up the locking washer on the outer nut. The same applies to the front, and has no interaction with the axle or drive flange.

The axle movement you are talking about sounds like the drive axle is moving through the drive flange. That does not sound right! The nut on the drive axle should be tightened to 10-15ft/lb, which I would have thought should be enough to pull the axle in to the drive flange and prevent any movement. However unless the nut bottoms out on the thread, I can't see how the nut can be tightened whilst still allowing the shaft to move through the flange, and if the nut has bottomed then the axle is too far through the flange indicating the shoulder on the spines or the mating surface on the flange have worn significantly.

It is possible that the nut, when last fitted, bound up on the thread (dirt?) and was tightened to torque without pulling the shaft to the correct position? Or possibly the mating surfaces of the axle splines and the drive flange have worn allowing the movement? I have one rear axle where the nut was not pinned, came loose and allowed the shaft to retract in to the diff, after which it simply reamed out the splines on the shaft and drive flange!

A simple check would be to try to tighten the nut, if it is loose and when tightened it pulls the axle to the correct place and loses the float, then the current assembly is incorrect. If you remove the felt seal, the shoulder where the axle thread ends should be well inside the flange (the felt seal should sit in that recess). Also it would be wise to check the shaft and flange splines!

[Wolfman_TWP]

This type of thing was brought to my attention the other week. I was purchasing new drive flanges for the front of my S3, and was asked if I had the clips that fit into the flanges.. (Not sure whether the S2's need them). But that free play may be due to them being missing..

Inside the flanges is a thin groove, these clips pop into that.. So when you tighten the nut it pulls the axle against the clip and stops it from moving about. (I don't have the part numbers for them here, but can pop them up when I get home)

Wolf

[Warb]

I can't see anything like that in the SII/IIA parts book. Just the nut, one washer and the felt seal. I'm still guessing the shoulder on the splines is supposed to be pulled on to the back of the drive member by the torque on the nut.......

[geodon]

Warb, thanks for a very well thought out reply. I'm *fairly* sure the nut is hard up on the shoulder of the axle splines.
Point taken on the dial indicator.
Off-side is now in bits but near-side is still intact. ( I NEVER strip both sides when I don't know what I'm doing!)
This car has Selectro FWH and this means the drive flanges are not original issue. I think the one I removed was very light. Aluminium?? If they are not as deep as the orig, the securing nut will bed down without pulling the axle all the way home leaving some free play which tranlates into end float?

I'm in the sticks till Wed night so will follow up with photos then.

[JDNSW]

There appear from the parts book to be three flanges. The first is 571235, which was fitted to all 2 and 2a (except those with salisbury rear axle), and I think is interchangeable with all Series 1, and all S3 88 to July 1980 - in other words, the twelve spline one. The second is 571711, all S3 109, and 88 from August 1980 up to October 1983, when it was superseded by FRC7013, also 24 spline. None appear to use clips. The only clip I can see is the circlip used instead of a nut on Stage 1 S3s, but it fits the drive axle stub, and the groove is in that not the drive flange.

John

[Warb]

This car has Selectro FWH and this means the drive flanges are not original issue. I think the one I removed was very light. Aluminium?? If they are not as deep as the orig, the securing nut will bed down without pulling the axle all the way home leaving some free play which tranlates into end float?

I've never taken Selectro's apart, so I don't know what they look like inside. As you say, if the depth of the hub is less than the distance between the shoulder on the splines and the shoulder of the thread, then there will always be end float.

Generally speaking, splined joints are designed to be "fixed" rather than sliding - except when specifically designed as sliding joints (like propshafts). Having no moving parts that need lubrication or expansion space, end float is not really desirable!

I have in front of me a PowerLock freewheeling hub (P.O.S. if ever I saw one!), an original Series II drive flange and a front axle - actually that's in the shed covered in grease! Measuring the splined section on the drive member, from the front to rear faces gives almost exactly 30mm for both the factory drive member and the PowerLock hub. Measuring the axle, from the shoulder at the end of the thread to the shoulder on the inside end of the splines gives about 25mm.

So when the axle is fully inserted in the drive member until the shoulders on the splines meet the back face of the drive member, there is still 5mm of "pinch" available. The same applies with the PowerLock, as it is the same depth.

That 5mm recess at the front of the drive member is ample for the felt seal (which is still fitted with the PowerLock), and tightening the nut to 10ft/lbs as specified locks the axle to the drive member (or hub) with no possibility of movement.

I somehow doubt that the Selectro is supposed to have end float in the spline. If it is not as deep as the axles spline-shoulder to thread measurement, then I'd suggest that either something is badly worn or perhaps you're missing a spacer?

[geodon]

Measurements & photos Wed night!

[I've never taken Selectro's apart, .....]

Take a look @ Wolfman's link 5/12 11.35am:



http://www.aulro.com/afvb/series-2-2a/140031-selectro-fw-hubs.html

Print it out & file it!

[geodon]

The attachment of the axle via the big nut is pefectly normal but it's to a sliding hub.

This sliding hub is splined to the drive member that bolts to the wheel hub ie the connection is not "rigidly fixed" as it is on normal drive flanges!

In effect there are 2 sliding connections for the axle. One at the diff & one at the FW hub. On the original set up, one end (at the drive hub) is fixed hence no endplay.

It looks like that's the price you pay for FW hubs??

It is of no consequence if the FW hubs are "free" as the axle does not rotate.

AND it MAY be that when the FW hubs are engaged, the end float is taken up but I don't if that can be checked without taking out the diff.

[Warb]

Glad you got it sorted out!

With the PowerLock hubs the drive shaft connects rigidly to a steel star gear, which (when the hub is unlocked) rotates on a nylon bush. This set-up gives perhap 10 thou of end float, though of course that may be due to the bush wearing over the years of use!