Jag rear axle end float

[millsd60]

Guys

Fitted the rear wheel to my GD's back axle for the first time last night, and after standing back and admiring my handy work. I started to push pull and poke, only to find that there is what seems to me to be an excessive amount of end float on each rear wheel. This has only become apparent now the wheels are on and I can push/pull with some purchase.

So what is it….. I think I have traced the problem to the rear hub carriers as everything else is new including drive shafts and UJs. I have taken the hub carriers off again and found that there is a Phosphor bronze bush fitted into the inner race of rear bearing of the carrier and I think that is where the end float is coming from. I have measured the end float and it is 3-3.5 thou, not excessive, but with the wheel on it seems to much for my liking. So is it a case of making a new thicker bush (by 4 thou ) to take up the slack and add some pre-load into the bearings, or is there something else I don't know about. Any suggestion/advice would be appreciated.

Dave Mills

[Glyn_Turner]

Dave

Out of interest, did you buy this as a reconditioned axle or have you done the work yourself?

Glyn

[millsd60]

Glyn

Removed the axle from a very sorry XJS, but it drove fabulously. Yes have done the work myself, 'not suprised then' do I hear. I have basically replaced every thing except the hub carriers.

I have made a thicker ph bronze bush and fitted in but it has made no difference, in fact I fitted both to make sure there was no end float but no difference. Am now totally confused. Mearsuring with a dial gauge mounted on the drive shaft with the foot of the gauge against the hub carrier there is 5 thou of play, but where is that play is the question? It can't be in the UJs cos they are new, so it can only be in the hub carrier, but where?

If I buy new hub carriers from Ward Engineering will they need adjustment or will they bolt on and be right from the off.

Anyone been hear before?

[callum]

I've done the complete job on my GD and the symptoms you describe are puzzling indeed. The hub needs a press to split it normally and a vice to close it up as the splined drive shaft stub needs to be mated to the bearing carrier with hd loctite to prevent movement and galling/wear. The spacer shims take out very small variations in bearings and alloy castings. In my experience OEM bearings normally only need the same shims fitting to each wheel station whence they came. My suspicions focus elsewhere. If the XJS was OK then it is the bits you've changed that attract my interest. What did you do to the diff? Replaced the seals? Properly torque the drive output shafts or have you crushed the collapsible spacers in the diff? These are best punch marked before disassembly and then count the unwind so you can re-torque to spec by aligning the punch marks. Is the disc and carrier set up shimmed centrally and tightened up? or is the movement not in the drive shaft at all but in the torsion bar yolk - the outer pivot bearings? Are the wheels tight to the mounting flange or are you using short nuts that go on tight but don't actually clamp the wheel?:'(

[paul]

When you say end float with the wheel fitted are you sure the movement is in the diff as it could be in the lower trunnion ??? can you see the disc's moving.
When I changed my diff from a 2.88 to a 3.31 I had the diff rebuilt and the only thing he couldn't replace was the output shaft bearings as these were of the old type although they appeared to be serviceable after one track day I got nasty metal to metal noises when I checked to see if the disc's were moving by getting someone to rock the wheel top to bottom I had several thou of movement Although when the output shafts/carriers were removed and then checked in a lathe there was only 1+thou difference but obviously this is added up by the distance of the disc.The remedy was that I had the later carriers of my 2.88 fitted with new bearings and put them on the 3.31 and hey presto perfect the only thing I had to check was the disc centralisation(shims) and camber shims
cheers
Paul

[millsd60]

Callum

Yes your right I changed the oil seals in the diff. Fitted new collapsable spacers and although I didn't torque them or mark their position with a punch, I followed the manual as best I could. I am convinced the play is not in the diff cos I have had a dial gauge on the drive shaft and can see the 5 thou measuring to the rim of the hub carrier when pulling and pushing the hub carrier.

Yep the wheels are tight......
But the spline of the drive shaft slip in and out of the hub carrier very easily, no vice needed. However I cant see how that effects the end float. The other odd thing is that is seems the same on both sides?

Did you have anything like this when you did your axle?

[wilf]

Dave - I know what you mean, with the rear end up in the air there does appear to be a lot of play in the rear wheel bearings on my own car. However, bearing endfloat is specified at between 2 and 6 thou. Mine comes out at 4. The spacer thing you see in the assembly is the item which controls the end float - to reduce it you put in a thinner spacer so that the big nut on the end preloads the bearings more by squashing them up. It is not a collapsible spacer like in the diff. You could turn it down a thou or two in thickness if you wanted. Just make sure that you have pressed the inner races of the inner bearings right up to their shoulder.
Out of personal preference, I would probably reduce the float on the easily adjustable front hubs to less than I have at the rear now, but it does not seem to give any problems on the road.

When you have sorted the thing out to your personal satisfaction, don't forget to put locktite on the splines on final (re)asssembly. If you don't you will get movement between the splines and the hubs. Don't use the ultimate grade of loctite - the "medium" strength one is correct I think. This is a bit*h to do and keep grease out of the splines! Could be worth chatting to Ed Ward - he is very helpful and a mine of info on jag back ends.

Lastly, do not be surprised if you can get slight movement even in new UJ's - I believe this is common. Oh - and double check to make sure the float is not coming from the diff output shafts - it really is very difficult to get that damm collapsible spacer thing right - I know!!

HTH

Wilf

[millsd60]

Thanks Wilf

Yes I have conversed with Ed at Ward engineering and he has mirrored what you have said. My new approach will be reduce the bronze sleave thichness by 2 thou at a time and see where that takes me. Ed has also said check the UJ cups are fully home, cos if they aren't, that can cause some play and I did notice whilst I was poking around in there that one wasn't fully home. So I now have some ways forward, or at least some enthusiasm to keep going.

P.S. What is the Crendon like. I nearly chose it instead of the GD. But sorry mate I was seduced by the way Andy Burrows scared my in the GD. And hey, I think your a help, not a trouble maker.

All the best

Dave Mills

[wilf]

Dave, you are welcome. My "troublemaker" tagline stems from when I was campaigning to keep the forum open to all, not restricted to CRC members. Maybe its about time I changed it to "(un)official nosey bu**er".

The Crendon is just fine, I am sure that if you read some other posts you will see what a fan I am. But... it is a totally different entity to a GD, with different aims and objectives. You already know that those objectives align with my own!!

In all seriousness, I enjoy driving the Crendon, it is comfortable, handles well, and with the fairly stupid engine I put in it, fast as hell! And it looks authentic. What more could a guy ask for?? (maybe Claudia Schiffer in the passenger seat?).

Don't give up on the jag rear end, they can be sods to set up, but once done will serve you well. Just remember that the best selling US kit uses a live rear axle from a Mustang.

Wilf

PS, if you still need scaring, ask me to take you out at one of the shows!

[STEVE T]

OH Wilf "a stupid engine " what else can you say .
It was Meena that sold me my Gd how could i resist!!!!!


Regards Steve T