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You make a very good point. Based on that, replacement OEM bearings in the same hub should be able to be used with confidence with the original spacer. Compensating for wear over the life of a bearing, not so much.Quote:
Originally Posted by roverrescue
Genuine question... what wear in the bearing needs to be compensated for? Are you suggesting that either the bearing race or rollers wear down, i.e. material is consumed, introducing additional end float (slack) within the overall assembly that has to be adjusted for?Quote:
Originally Posted by POD
I only use Timkin bearings, and have spares of same on hand, so assume the only circumstance in which I'd need to change the spacer is if it became necessary to change the hub. It suits me to retain the spacers.Quote:
Originally Posted by POD
From what little I know and have read
Tapered roller bearing wear characteristics and life spans is up there in the Mechanical Engineers “We can debate this all night long” playbook!!
I think in this day and age of high tolerance / high strength alloys essentially a tapered bearing and race overall tolerances will remain on specification up to the point of failure.
I recall John from Western NSW saying he is still running well lubricated wheel bearings from 19dicketytwo with 917 thousand miles on them!
But seriously. Bearings die due to contamination or lack of lubrication. I would hazard a guess that if you measured the overall stack height of John’s well matured bearing and race against a brand new Timken there may indeed be some measureble variance
BUT I would also argue that the variance would be pretty insignificant !!!
Steve
Thanks for the info on this thread, I need to do the front brake pads and I've been trying to figure out the effort to regrease the bearings at the same time. From this all I need is a couple of new nuts, a big socket and a torque wrench. The explanation of how the spacer system works and the fact that you should be able to reuse the existing spacer with regreased or new bearings is a huge win.
Regards,
Tote
You might like to have a couple of bearing seals to hand as well - I replaced mine...Quote:
Originally Posted by Tote
Good luck
the end float (fore and aft movement) that you refer to is taken up by pre-load and the stake nut. i think you meant to say the bearing is able to move laterally (or concentrically) on the bearing cup as the bearing material is eroded. To some extent this is also taken up by pre-load on the stake nut as you push the cone into the cup taking up the tolerance (until a point that the tolerance is too much). the spacer is against the bearing cup and doesn't affect pre-load of the stake nut save to say it offers a second point of contact to prevent the bearing cup moving out of its perfect vertical plane. as others have said, it was LR's way of making the process idiot proof (and i thank them for that for i am dangerous with a spanner and hammer). For what it is worth, on my 35 spline sals conversion the outer bearing ID is a bees **** smaller than the inner bearing, with a small shoulder against which the bearing cup rests for pre-load. Hard to see in the pic.Quote:
Originally Posted by Samblers
Attachment 168761
Yep, just making the point that there is zero adjustment possible within the Puma assembly. The bearings are rigidly held in place between locknut, spacer (not shown, at pencil tip) and stub axle.Quote:
Originally Posted by MLD
Attachment 168762
This is a bit difficult to follow but if I understand what you're saying, I'm sure it is incorrect. The spacer is between the two bearing cones, not the cups. The staked nut is tightened down on the cones but can only move them as far as the spacer allows- unlike the older style where the adjusting nut being tightened too much will result in excessive preload by moving the cups inward toward each other and deeper into the cups. With the spacer, the nut can be tightened as much as you like but the cones will not be preloaded more than the spacer will allow.Quote:
Originally Posted by MLD
I know a bloke is not supposed to say this, but the information in this thread- particularly roverrescue's points- have prompted me to actually consider this and to change my mind about the spacer setup. When I think about it, it is of course correct that it is the hub casting and machining that will have variation from one to another, whereas the modern bearings will have effectively zero variation from one to the next and the wear will of course be as good as zero over the life of the bearing; so, unless one is replacing the hub- and assuming OEM bearings are used- the spacer will give the correct preload every time. This principle would apply to such things as diff pinion bearings and transfer case bearing spacers also. Way back when I was learning this stuff, they were not used so I have regarded them as a modern shortcut to be spurned.
Totally agree with you POD.
Both setups can clearly work, but after thinking about the merits of both, it's clear why the switch to the locknut/spacer design was made, hence I chose to stick with it.
Quite enjoying the torque wrench too...
Sam
