I'm sure I screwed something up and I'm guessing it was when I installed the hub and castle nut back on. It was too difficult to remove the old bearings, so I brought my mechanic the hub and bearing kit. I had read that it should be torqued to 100lbs and that's what I did. If that is the correct spec, the only thing I can think is that I used kgs on my torque wrench, rather than pounds. My mechanic packed it with grease when he installed the bearing and seal. I ordered a new bearing kit, but I'm curious if there is a step or something I may have missed? I probably put on 5k miles over the time of new bears to them going bad again.

Thanks,

 

What brand bearing? Timken, SKF or National are now usually made in China and are generally are OK, Many other low cost brands like WJB are not good and failure after a few thousand miles is to be expected.

Take the old bearings out, degrease them and get a good close look. Do some failaure analysis, that will tell the story. Discoloration or groovs means they got hot (too tight), cage damage or wear on the ends might sugges they were too loose. Rust spots right sugges water contamination. Chips or galling might mean soft or impropper heat threat. Have a look at this linked below.

https://www.timken.com/resources/tim...er_7352-small/

 

Thank you for the link , I will definitly take a look for potential causes. I ordered them from Moss, which I typically consider having good products, however the brand is not listed in the description. I do see in the picture the name stamped on the outer casing is Powerhouse. I'm not sure if that's actually what I had installed, just from the listing pic.

 

Probably "Powertune". Do a google search for Powertune Bearings, lots of discussion of them being overseas junk and reported failures. It's a common problem as inflation has caused quality parts to skyrocket so vendors go down market and hope for the best in search of profits with ZERO reguard for your time or personal safety.

You might want Timken, RockAuto.com sells them for about 22$ EACH. The cheap-o units sell for 5 to 7$ each. Companies like Moss aggrigate these items (bearings and seals) in to low priced kits which appears very helpful to the DIY'er but I learned long ago this is folly in many cases.

 

Well I called Moss and sure enough they are Powertune bearings. I'd already placed the order for another kit, so I guess I'll be returning those. I was having a hard time determining what bearings and seal to purchase originally because of the change in sizes over the years so when I saw the kit, I just grabbed it. Anyone happen to know part numbers for quality bearings for 1990? Thanks for the heads up on that brand, I just assumed I messed something up, didn't even consider bearing quality, makes me feel a little better about myself

 

Hi, Greg in France has done an excellent ‘sticky’ on rear hubs, probably worth a close read in this case as it explains ‘end float’ when installing new bearings.
Unless you have been particularly unlucky with a set of defective bearings, my money would be on in correct set up?

 

The spacer/shim usually sticks to one of the bearing races (covered in grease) and people unfamiliar with this setup throw away the spacer/shim with the old bearing and reassemble with new parts.

The shims are sold in various thicknesses but I re-use the original because someone at the factory spent time to measures and set it up properly.

 

Herewith the bearing setup procedure. the castellated nut should be torqued up to 140 llbs/ft.

https://www.jaguarforums.com/forum/x...shafts-263094/
See pdf attached to the first post. The endfloat setp section begins just after photo 20. Subheading: Setting the rear hub endfloat/preload

 

TIMKEN 18690 Wheel Bearing TIMKEN 18590 Wheel Bearing TIMKEN 18520 Wheel Bearing TIMKEN 18620

In the event anyone ever needs it, I linked what I ordered. Also, I did disassemble most of the hub the last time, so I know the shim was present when reinstalled. When I went today to my mechanic, he said don't bother with the Powertune, so I ordered the Temkin. I kept the kit for the seals, but got quality races and bearings on order.

 

Just thinking out loud here. Shims are needed because the hub is machined to tight tolerances on the bearing bore diameter but fairly wide tolerances on the bearing bore depth. The shims are set at the factory to provide the correct end float, so the shims and hub are a matched set. Re-using the shims (with the same hub) works because new bearings are precision ground to the exact same dimensions as the originals.

I wonder if that assumption holds true that the new bearing is exactly the same "depth" as the originals for the low budget products available nowadays. I'm probably over-thinking this (I usually do), but a micrometer check wouldn't be a bad idea to confirm the new bearings are indeed the same depth as the originals.

HTH, Dave

 

See post 8 above. You definitely need to measure the shim size required, in my view. It would be quite a waste of effort to do the rebuild and not check it. However, what you say may well be true, as bearings are usually made to absolutely microscopic tolerances!

 

Looking at the Timken online tolerance tool for bearing 18690 / 18620 which is the outer rear wheel bearing setup:
: https://engineering.timken.com/engin...ng-tolerances/
The overall max tolerance for the 'width', which is the width between the bearing cup & cones when assembled & what matters when setting the rear end float, is 0.0000 - 0.0080 inch.
Which is actually pretty large & does imply that you do need to check /replace the spacer to match.

in practice I'd guess this is basically always a near 0 tolerance, & I just reused the old spacer and it was perfect. Just make sur you clean everything up perfectly, run some 1000grit wet & dry lightly over the face of the bronze spacer & the bearing recesses etc to ensure no raised bumps.