How much torque?

[kebabman 0]

Replaced the rear discs on my VR6 about 8-9 months ago, did the bearings at the same time, and they're knackered already. :roll:

 

I can see whats happened, the hub nut wasn't tight enough, I've driven around with too much play in the wheel and not noticed until the bearings got noisy.

 

I've got a Porter manual (which is shit btw) which covers the Corrado vaguely, but they don't specify how tight you need to do the hub net to seat the taper bearing. It just says "tighten nut to the specified torque, then back it off again until you can just move the washer behind with a screwdrive." Look in the "data" section and it's got no number for the VR6 rear hub nut.

 

So...I did the hub nut to the highest setting on my torque wrench (210nm), and then backed it off like it says. Drove fine, and I checked the wheels after ~50 miles and there was no play. All good. When I checked them this evening after a few thousand miles, and there was definite play in both the horizontal and verticle, not loads but too much none the less. Tightened the hub nut up again and then backed it off a bit less this time hoping I'd get away with it but the noise was still there. :(

 

So now I've got new bearings, how much torque is required to seat them? And how much should you back the nut off after?

 

Any help much appreciated!

 

Cheers. :)

[TREVR6 0]

The best way I believe is to do it by feel. With the wheel on slowly nip the nut up until there is no play but the wheel turns without the bearing dragging. Then take the wheel off and put the split pin etc in... I suggest giving the bearing a good tighten (210 is a bit on the harsh side tho) before the above procedure just to make sure it's seated properly. Also check and adjust after a week or so once the brgs have bedded in a little, you may need to nip them up just a touch, but then that should be them OK for good, make sure you take time to massage the grease well into the rollers too, no garage floor sweepings allowed in the grease mind :nono:

Buy top notch brgs too cos cheep ones don't last

[RW1 0]

The noises are cos the hubs have been severely overtightened!

 

Rear hub bearing nuts have no torque at all. Spin the disc/bearing and tighten until the thick washer behind the securing nut is just pushable with a screw driver. The disc being turned should not feel as though it is binding but will be a little stiff.

 

Final check with the while bearing assembly, split pin in etc., and bareaing cap cover in place and wheel back on, jack it down, put in gear on reasonably level ground, handbrake off. Now put your foot on the top outer face of the tyre and make the wheel rock into and out of the wheel arch. ie. at right angles to the wheel rotation. You should only hear/feel a faint clunk or nothing at all. If it clucks in both directions quite noticably, the bearing is too slack.

 

Slight overtightening of the bearing is like an sixteenth of a turn while slowly turning the disc from where it feels that it finally has finally bedded down but "good tightening" is miles to high! It may damage or distort the bearing assembly items.

 

I'd recommend that the bearings are changed again as they may have been damaged/distorted by the stress due to the 210Nm tghtening.

 

.

[andy 0]

Yep you've mullered them through overtightening!

[kebabman 0]

So you're saying don't tighten them to seat the bearing? Just do them up to the point where there is no play in the wheel/the washer behind is just moveable? Won't it go slack as the bearing settles?

 

The wheel spins freely and I've got rid of the play by tightening them up a bit, but it's still making a nasty noise. Always thought you had to tighten up then slack off taper bearings so they seated properly when in actual fact I was knackering the bearing. :oops:

[Kevin Bacon 5]

What you do is nip up the castellated nut with a socket so there's no play to seat them, spin the wheel a few times, then you back the nut off again and just gently nip up the nut a fraction more than hand tight.

 

These bearings need free play to counter heat expansion mate. After a few hundred miles, check the play. There should be the slightest amount of lateral rock when you grab the wheel and move it in and out.

 

It's a schitt design and a lot of MOT testers don't take the required free play into account as most modern cars use sealed ball race bearings at the rear (smaller versions of the fronts bearings) which don't have any play.