though I’m not through MoT yet, I may give an interim report. As for the steering it turned out the inner tie rod end was entirely play-free, but the outer tie-rod end was shot. It was easily replaced - unfortunately I’ve got JLM 409 + a metric outer tie-rod end lying around that won’t fit my steering rack as the inner thread is metric as well.
As for the rear wheel play I was surprised the hub carrier came off quite easily. We saw that it was much easier to skim the spacer than to work our way through to the wheel bearing which looked as new. Only upon reassembly we found the play was still there … and identified the inner u-joint as the source. Robin and Aristides, you’ve earned the medaille d’honneur for suspecting it from the beginning! Luckily, I had an extra u-joint lying around and it took us one evening to pull the half shaft, remove the old u-joint that was obviously damaged at one “cup” and replace with the new one. Today we reinstalled the half shaft. Unfortunately, with the outer flange reinstalled it wouldn’t fit through the twin spring units and we had to remove the front spring/shock unit first. I was struck again by how well all the big nuts came off and were perfect to be reinstalled.
Due to the skimmed spacer there is hardly any play left in the bearing - I’ll keep my eyes open and - if necessary - get the new, original and correct J spacer (3.38 mm) to restore the original function.
So, now let’s keep fingers crossed!
Thank you all for your advice! Have a nice week end
An easy and inexpensive solution Jochen!
I imagine that you repacked the bearing with new grease, so I think that, at least for now, you are good to go.
we left everything pretty much unaltered at the wheel bearing: the grease was clean and the bearing (after only around 120 000 kms) as good as new. As the left inner u-joint was visibly damaged (some bit of the shell of one cup had broken out - why?), water had entered and rust developed, we just replaced this part and didn’t care too much about the right side.
As I mentioned - my first concern about symmetry now is about that spacer we skimmed unnecessarily and different from the spacer on the other side.
Jochen, the spacer wouldn’t necessarily need to be the same on both sides unless both sides happened to need the same amount of adjustment. Since you skimmed the spacer and still have a little play I sure wouldn’t go back to a thicker (non-skimmed) spacer. Sounds like you made it better and that’s where I’d leave it.
You’re right, of course. I won’t touch it unless required. I’ll check for heat in the wheel hub and - if I don’t find anything life is good. It’s just that it really bothers me that I messed up something that probably was perfect before:-(
That’s why I asked how is the other side.
Spacers do not matter, end float does.
Did you measure/feel the play of the hub before and after?
As I said before, I’ve put some preload on mine, tapered bearings run better and longer with preload.
I would also be concerned with symmetry, so if anything, and if there is a big difference, I would bring the other side at the same specs as the one you skimmed.
yes, there is a small rest of play, but now a lot less on left hand than on right hand. As I said, I’ll check for consequences (noise, drag, heat), and, if any of them occur, I’ll resort to dropping in another new J spacer to restore the original play. Though maybe a very uneducated guess I’d prefer to maintain some play on a tapered roller bearing.
I’d assume that on later cars Jaguar did away with the play as one of the shortcomings of their rear IRS, the lack of any upper guidance became obvious.
For the moment I’m very curious what our MoT will say about it on Thursday:-/
All bearings must have play for lubrication, Jochen, as specified by manufacturers - to tight and they will overheat. And is specified throughout by Jaguar.
For ordinary bearings the play is built in during manufacture, for conical bearing the play must be set by relevant procedures…
Yes, and that a little too much preload is far worse for bearing life than a little too much play.
I have never heard of play for lubrication, more like the preload increases a little because the thin oil film that is squeezed out of the grease is probably stronger than anything.
The jag manual says to back off 1-2! Flats which seems a little loose.
Jaguar had a change of heart at some point. Not sure about XJ40s but the X300/308 spec is for pre-load, not free play, on the (conical) rear hub bearings.
[shrug]
One has to wonder, though, if it was the best decision. Not that I’ve done an analysis, mind you, but rear hub bearing problems seem more common on those cars than on our earlier models. Could this related to other factors? I dunno.
OTOH, here is not the first place I’ve heard that pre-load is actually the preferred method.
We can all agree that too tight or too loose is problematic. My experience is that, in terms of wear or damage, a bit too loose is less problematic than a bit too tight. Surely the designers are faced with the same coin toss and make the decision they feel is best at the time.
One thing about the rear hubs on our older models is that the bearings were very generously sized and will seemingly soldier on almost forever, even though lubricating them is an iffy proposition and there’s often too much play while remaining smooth and silent
It’s likely more related to accessibility/precision, Doug. To measure play in rear wheel bearing is easy even in situ; to measure preload, torque value, really require ‘bare’ bearings, without external components interfering with torque. Typically; on front wheels we use preload, rotating the wheel while feeling the resistance - not very precise compared to play, but adequate. For diff pinion with collapsible spacer, there is no practical alternative to preload…
Main point is that there must be no metal to metal contact in a bearing - there must be room for an oil/grease film. Without lubrication, play or not, a bearing is quickly ruined. And with too much play something gets sloppy - and with alternating directions of loads the bearing also will take a hammering. But within reason; I agree that a bit too loose is better than too tight…
