…‘if any’ is somewhat ambiguous, Mark - either play is 0,002" (which is good) or it is not (which is not)…
Using the ‘master shim’ has two purposes. It is precisely 0,15" - allowing computation of the of the correct shim by reading the play. The second purpose is to ensure that the inner race of the bearing does not slide up the hub when the hub carrier is lifted to measure play…
When the hub is lifted to measure play; the outer race will push on the inner race, causing the latter to slide up the hub. Which will affect the play readings - causing confusion.
The initial use of the ‘master spacer’ prevents this as it can be held firmly down while the hub carrier is lifted. To do this without the ‘master spacer’ is ‘difficult’…
The alternative method is indeed as Aristides suggests. It requires the driveshaft to be inserted in the hub, using nut torque to crush the solder (or whatever) to the correct play. Then replace the solder with the appropriate spacer - all of which is a somewhat tedious procedure. But equally effective - then verify endfloat using the procedure described for measuring in-car…
This is in fact the procedure used on the diff input shaft bearings. Except that the crushable (sleeve) is set using preload - the force required to initiate shaft turning. Which is not spec’ed for the rear hub. The reason the crushable is used on the diff is that to change shims the diff must be disassembled each time…
It’s essential that the play is to spec; too tight and the bearings will rapidly fail due to insufficient lubrication/overheating - and possibly bearing spinning. A bit too much play is less catastrophic…
There isn’t any bearing sliding going on. The both inner and outer bearings are pressed (interference fit) on the hub and don’t move. There is barely any up and down movement. I can’t feel it, but the dial indicator registers .0002" but I don’t know if that is truly accurate. My dial indicator is not a Starett, and is fasten with hand clamps to the side of the carrier. So a .002 movement on my dial indicator is questionable. Nothing like second guessing your tools. Ugh!
I’ll look at again, worse case I’ll press the hub out again. I’ll waste another seal, but that’s acceptable loss.
Check out my other post about the JB Weld seal retainer. This IRS has seen some hard life. after both carriers being screwed up, this is forcing my hand to look at the internals of the Power-Loc. This something I really wasn’t planning on doing. The existing seals didn’t show any signs of leaking so if it’s not broke, don’t fix it. Right?
I’m even questioning that. The JB Weld carrier had .004 end float, the seals looked ok, still had some soluble grease on them. I seriously considered leaving as is. I’m glad I didn’t. The carrier bearings were all binned, the were obvious signs of moisture ingress. The grease was beginning to solidify - like rock hard solidify.
If the force used to press the inner race on to the hub is applied to the ‘lifting’ of the hub carrier, Mark - the inner race will move…
Admittedly, some force is required, but as levers are used while lifting the carrier…
I was just puzzled by your report on erratic play readings - trying to find a explanation. However, as the inner race is seated on the hub by the ‘master spacer’ it has a play of 0,15". Removing the mandrel and fitting the computed shim leaves a play of 0,15 minus the shim thickness.
So your ‘preload’ idea, using the mandrel to force the inner race further down on the hub, took up the slack. And you now have the play intended by the computed shim - 0.002".
Which proves you got the mathematics right - and the play!
But ‘preload’ doesn’t enter into the picture; the shim abuts the hub and blocks any further inner race movement - maintaining bearing play. It’s all as good as it gets - I should have paid more attention to your post…
As one aside; the original grease specified for all greasing points was ‘Multipurpose Lithium grease, N.L.C.1 consistency No 2’ - to quote the good book.
As a second aside; as the felt seal gets soaked (invariably) by the grease - it is impervious to water, water repellent.
Both sides the inner and outer tapered bearings were a interference fit; requiring a press to remove and install the inner and outer bearings. I used the mandrel to establish the proper inner bearing position. In doing so, I could move the carrier up and down with a pair of screwdrivers. The bearings didn’t move on the hub; just the carrier.
I positioned the tip of my dial indicator on the inner race on the inside bearing; with a preload of about .050 on the indicator. I could move the carrier up and down with a pair of screw drivers. That is how I determined the end play. I wasn’t satisfied with that much end play, so I used the press, and pushed the inner bearing on to the hub a bit farther. Now I have between .002 to .000 end play. Like I mentioned above, I’m not sure if it’s my series of clamps holding the dial indicator that is moving or if I actually have .002 end play. I can’t feel any end play by putting the hub between my feet, and pulling up on the hub (like I could earlier in the post).
There was so much play, It bothered me. that’s why I pressed the inner bearing on a bit farther so there wasn’t play between the two bearings (inner and outer)
Does this make any sense?
It’s nice to know the purpose of the shim. to keep the bearing from moving on the shaft under load. If understand then the bearing and shim should be flush, to one another. Right?
I’m still not on board with this hole felt seal. both sides of this IRS; there is clearly signs of moisture ingress. the felt seal retainer rusted. there is water mixed n with the grease on the tapered bearing itself.
I figured I’d give the rubber seal a go. I just am not sure where the shims are supposed go now.
The other piece to this puzzle is if I do use a rubber / metal seal. there isn’t any place for condensation to go. So unless I completely fill the cavity with grease, I will be back to square one? felt or rubber?
Once again, probably over thinking… Paralysis by analysis?
Shouldn’t the felt seal be soaked in oil and the rest greased?
I think felt seals have been the preferred choice for sealing in these applications. Steering columns and other low-movement areas. Back in the early 1900s. I don’t exactly know why, but at least felt will hold up some time when neglected.
Hmmm …I am not sure about that. If the bearings have been selected properly they will be happy to run for more hours than your Jag will ever be asked to do. And these particular bearings do not really do any work …quarter of a turn if you’re unlucky!!..so provided their static load rating is comfortably about the applied load they will last for a very long time…even with marginal to zero lubrication. A bush , on the other hand, is reliant on the presence of some sort of lubricant to function properly. And way less tolerant of contamination.
As you press the inner race on to the hub with the master spacer; it gives a play equivalent to a 0,15" spacer. Ie, deliberately too large. Just putting in the correctly computed spacer leaves the inner race where it was. So you have to, and did, press the inner race further down to acquire the right play…
Indeed; the shim abuts the hub and the inner race abuts the shim - all ‘flush’…
Similarly; to increase play if one gets it wrong - the inner race must be moved up the hub, and a recomputed shim used
0,000 to 0,002" is ‘right’ is arguable - it says 0,001 to 0,003" in the ‘good book’. You should only have one reading; 0,002" is jolly perfect - 0,000 is not.
You should really feel some play at the correct 0,002" - however, with grease in the bearings some force is required to get metal to metal contact for correct play readings. No play is ‘not good’ - particularly since there is no discernible difference between ‘no play’ and high force already on the bearing …
the lack of movement and gravity causes the grease to settle. away from the bearings so there isn’t adequate lubrication because there is very little movement. less than 5% at any given time.
I understand why tapered bearings where picked because tapered roller bearings are great at keeping things in alignment when both axial and lateral forces are present. Bushes work well for loads and little rotation. Bushes are ideal in well lubricated applications. Dry bushes looses it’s ability to maintain alignment. I’m sure there’s a penis joke in their someplace So I guess there isn’t a “perfect solution” so, ya piss with the cock you got; so tapered bearings it is.
That makes sense; I will review and remove the bearing and start over if need be. Thank you for taking the time to put it in words I could understand.
What would you recommend given the current time crunch; use the JB welded carrier or not? I figure since it’s the seal, no harm no fowl. worse case I have to replace the hub. It’s not like the cage has to come out, again.
Rolling element bearings have two load specifications, a static load and a dynamic load. The manufacturers specifically design the bearings for the load case encountered in the lower suspension arm. Also…needle roller bearings have a substantially increased load carrying capacity than a similarly sized roller or tapered roller bearing so it looks like a good solution to me. Plain bearings are a more complex solution in terms of the design required to get them right. The product of contact pressure and sliding velocity (called PV…) has to be carefully selected and adequate lubrication guaranteed to make them reliable. I would be reluctant to change this detail.
I have a how to video in the works - hopefully it will make this easier for the rest of us Jag owners who want to take on the challenge. the last two I had done I paid to have done at $3,000.00 US each. Not doing that again.