W-22 Front bearing questions

[andrei]

Long Story short-Needed service on '04 WH chassis 33k miles, new brake pads (not recall), new rotors(cracked), new front seals, new front tires, and alignment, in preparation for a southern states trip. Workhorse would not honor brake work-go figure. Fifty miles into the trip heard a whining noise, and felt a pull, pulled over to find extreme axle heat, melted front right oil sight glass, oil everywhere and lots of smoke on right front wheel.
Towed back to same authorized WH service center Sunday PM(thank you Good Sam!) and went over Monday AM to see what happened. Outer cone bearing was destroyed, and most troubling the threads on the spindle bolt were flat, stripped completely. A scary scenario. The service center realizes the gravity of the situation and are taking care of the repair, new bearings, new spindle, and will now do WH brake recall since they were able to order the new calipers.
This is not about bashing the service center, but obviously something went wrong. When talking to the mechanic he said "I torqued evrything to spec, I don't know what happend, maybe the bearing was not seated right" He was a long time mechanic, not inexperienced by my judgement, and was visibly upset and apologetic. This svc center gets great reviews compared to others around here in eastern PA, and I feel they are handling the situation as well as it could be handled.
So after all that, here is my question: When assembling the front bearing assembly what is the proper procedure, in terms of tightening the spindle bolt, and do you back it off 1/4 turn like I do when repacking my boat trailer bearings? Any additional insight, similar incidents would be greatly appreciated. Thank you for any help.
Andrei

[DriVer]

Quote:

Originally Posted by andrei So after all that, here is my question: When assembling the front bearing assembly what is the proper procedure, in terms of tightening the spindle bolt, and do you back it off 1/4 turn like I do when repacking my boat trailer bearings? Any additional insight, similar incidents would be greatly appreciated. Thank you for any help.

Andrei, The front spindle nut needs to be torqued to spec. I spin and rock and shake the tire to make sure it's on there. If the castle nut does not come into the spindle enough, the cotter pin hole won't show. So having extremely loose bearings is unlikely. What you are describing appears to be an incorrectly installed bearing OR sight unseen ... was the cotter key in the spindle?

Spindle Nut Initial Torque While Rotating Hub 360° in Both Directions
Back Off 1/4 to 1/6 Turn to Align Cotter Pin Hole (I like: Back-Off One Flat)

153 Nm 113 lb ft

[andrei]

Thanks for your reply. Unfortunately I did not see the cotter pin, I can ask the mechanic if it was still in, or whether the nut had pushed past it. This happened on a busy highway section where two major NYC feeder routes combine for a bit (78&81) Ironically we went that way to avoid 95 southbound. I should have taken the remnants of the oil cover off and looked, but there was a lot of semi trafic rocking the rig constantly. At the repair shop I looked at the castle nut and its threads looked, and felt OK? Only the spindle had crushed/flat bearings. There were no "thread shards" as is typical when something gets cross threaded. As I said, I am not sure if the cotter pin was there. I agree with you that the bearing was probably not in right, it then self destructed, got incredibly hot, which overheated the oil and melted the cover. I think it then started to push the rotor assembly outward, crushing the threads? I attached a picture of the melted oil cover in case you are interested, would not let me embed in email. Thanks again for your help, I will discuss the proper torque spec with the shop and check the wheels myself in terms of rocking, as well as spinning freely.