Tightening wheel-bearings?

|After replacing bearings on the front wheel of a sports car, I'm wondering |how far down to torque the castle nut before installing the cotter pin. | |There's a clear point where the nut is snug and in less than 1/6 additional |turn the wheel turns less freely. On the other hand, there's a slight |rumbling noise even with less compression than that. | |So - what's the guideline, if there's no manual or factory torque spec? | |Thanks- | |Ctenos

some wheel bearing need to be loaded under torque. Some do _not_. If you don't know which is which in your case, find out ! Loading a bearing that isn't supposed to be loaded will break a stub axle on you in no time. No need to ask me how I know about this.

Most wheel bearings get snugged up, then the castle nut is -backed-off

1/4 turn, and the cotter pin inserted.

HTH

Lg

What kind of 'sports car'?

Normally, you tighten to seat the bearings, then loosen and retighten, essentially finger tight, to just remove side play.

I don't know of any case where you can't use this procedure, but there may be some.

Sorry to be vague; didn't want to get into a long story. It's a bike-engined tadpole trike (2F1R), with "home-made" (not by me) wire wheels on stub axles from some unknown car. With everything one-off, there are no instructions! The bearings, I'm told, are a common one for trailers, so load should be no issue. I'll try the in-snug-and-back-1/4 approach.

Is a little rumbling with a hand-spin OK, or does that mean I got dirt or something in the bearing when removing the wheel for repair? I'm pretty careful, but who knows.

Thanks-

Ctenos

For me, a rumbling sound from the bearing would not be ok.

If you are going to follow this tighten and back off some fraction of a turn, at least check the sideplay. You don't have to have a dial indicator.

Ctenos wrote in article ...

First of all, I will assume that you are talking about a tapered roller bearing.

If not, then much of the advice on this thread might not apply - especially if it happens to be a sealed ball or straight roller bearing.

If there is a "slight rumbling" in your wheel bearing, things may take on a whole new level of "sporty" when the bearing seizes and the wheel leaves the car.

Find the bad bearing and replace it.

Then, tighten things until there is no in-out play at the bearing, back the nut off to the next cotter/lock pin hole and insert a new cotter pin.

While some tapered roller bearings may have enough bearing contact surface to tolerate it, I believe backing the nut off a quarter-turn will produce too much play in most.

Bob Paulin - R.A.C.E Race Car Chassis Setup & Dial-in Services

He didn't say that he re-packed the bearing with grease, did he? If it's rumbling with a good pack of grease, then that's not a good bearing. And if it's rumbling because he put it in dry, then just how does he expect to get the grease in there now?

Ed

Yes, that's right. And I did pack both sets carefully with clean grease before assembling.

I'm convinced! Avoided this step because these hubs weren't designed for easy removal of races (no puller grooves or pin-punch channels), and I don't like to bag around too much on a wire wheel.

Thanks for this and other group advice-

Ctenos

when I first replaced wheel bearings on my car I wasn't sure what I was doing. I followed the instructions in the Haynes manual and got the same results you did. I was probably being over sensitive. I tightened the nut and losened it a few times, rotating the wheel a lot to see what felt good, and then went with what seemed best. The first few times I drove the car I listened carefully and I got out and felt the hub with my hand to see if it was heating up from friction. Everything was okay. The bearings have been fine. I've since had the nuts off to service the brakes and this time it was a lot easier putting the nuts back on.

--

------------------------------------------------------------------------------ William R Watt National Capital FreeNet Ottawa's free community network homepage:

warning: non-freenet email must have "notspam" in subject or it's returned

The rumble either means it is too tight or maybe the bearing race/seat is washboarded out.

The last bearing that I couldn't get a rumble out of unless I made it way too loose only lasted a couple weeks.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's