Rear bearing procedure (1 Viewer)

[zapatius]

I had a rear end rumble I have been chasing. Ordered all new bushings for suspension components but also noticed play in the driver's side rear hub. Inner seal failed and bearings were full of gear oil.

I ordered the kit from Marlin Crawler. Thoroughly cleaned the hub, replaced the seals and put in new Koyo bearings with Lucas Green & Tacky grease. I used a Gearwrench bearing grease press and the bearings were thoroughly coated/filled.

Followed the FSM procedure. Set the preload at about 11 pounds with a fish scale and tightened nut until the marks aligned on the nut and flange. Clearance between flange and nut was less than 1mm, per FSM.

I drove city driving immediately after reassembly. Hit speeds of 65 over 10 miles and ended with several stop lights and stop signs.

I felt both rear hubs. One I just did was slightly warmer than the other side. I could still put my bare hand on it and hold it there but it was hotter than expected. I don't see how it could be too tight. I guess I could have a dragging brake but didn't notice abnormal wear.

Any thoughts or advice or errors in procedure? TIA.

 

[Malleus]

EDIT: this is for new bearings; I didn't reuse the old ones.

I just did this on two of my 80s. IME, the FSM spec is too tight. Both times I set the preload to the middle of the range, lined the nut marks up with the marks on the spindle and after the test drive, the hubs were too hot the touch. An infrared thermometer said over 180°. I pulled the cover and loosed the nut until it lined up with the next spindle mark. That seemed to be the right operating preload, but it didn't match the FSM spring scale load.

Thinking back on the procedure, it seems the preload isn't really critical (the preload range is really wide), as long as the bearings are seated it seems the preload is "right". I read through Timken's recommendation (the pub is 10424) for the rear bearing series and the only criticality they list is bore size for the hub, and that's a huge press fit (one of mine was nearly 0.004, which is at the upper limit). The spindle/bearing fit is a slip fit (which it has to be, you can't press it on, even if you have the axle out), so the shaft tolerance is really loose, for a bearing.

I think the objective of the procedure writers was just to ensure that everything was pulled up tight; the design seems to be self locating.

HTH

 

[zapatius]

EDIT: this is for new bearings; I didn't reuse the old ones.

I just did this on two of my 80s. IME, the FSM spec is too tight. Both times I set the preload to the middle of the range, lined the nut marks up with the marks on the spindle and after the test drive, the hubs were too hot the touch. An infrared thermometer said over 180°. I pulled the cover and loosed the nut until it lined up with the next spindle mark. That seemed to be the right operating preload, but it didn't match the FSM spring scale load.

Thinking back on the procedure, it seems the preload isn't really critical (the preload range is really wide), as long as the bearings are seated it seems the preload is "right". I read through Timken's recommendation (the pub is 10424) for the rear bearing series and the only criticality they list is bore size for the hub, and that's a huge press fit (one of mine was nearly 0.004, which is at the upper limit). The spindle/bearing fit is a slip fit (which it has to be, you can't press it on, even if you have the axle out), so the shaft tolerance is really loose, for a bearing.

I think the objective of the procedure writers was just to ensure that everything was pulled up tight; the design seems to be self locating.

HTH

Thanks for the info. The FSM picture showed aligning the approximately 2:00 marks, so that's what I did. It felt like it was well over the 45 ft lb of torque (iirc). So, as long as it's tighter than finger tight and a set of marks line up, I should be good? I agree there's a huge range in preload.

 

[Malleus]

Thanks for the info. The FSM picture showed aligning the approximately 2:00 marks, so that's what I did. It felt like it was well over the 45 ft lb of torque (iirc). So, as long as it's tighter than finger tight and a set of marks line up, I should be good? I agree there's a huge range in preload.

Now that I think about it, all the installs I did wound up at 2:00, too. At least for my hubs, yes, one mark below the "correct" fishscale preload seems to be the right way to go. I have to service the last hub on one of my 80s this weekend, and I may try setting the preload at the extreme low end of the scale and see where the nut lines up.

 

[zapatius]

I have about a four hour drive I have to make today. It's pouring rain and about 60 degrees, maybe that will help keep the hub cooler. I'll pull it back off tomorrow and redo it. When I took it off this time, the nut was able to be loosened by hand. Crazy how that happens.