Topic: Wheel Hub-Bearing Bolt - Socket Size? (Read 6357 times)

lizardland · « **on:** November 28, 2006, 06:13:37 PM »

Anyone know the socket size for the wheel hub bearing assembly bolts? I dont want to buy a full set of 12 point sockets just for one socket.

Any help much appreciated.

Ta,

Stuart

daggie · « **Reply #1 on:** November 28, 2006, 06:15:30 PM »

13mm & 36 for the big fecker

lizardland · « **Reply #2 on:** November 28, 2006, 06:27:19 PM »

Toastie · « **Reply #3 on:** November 28, 2006, 10:48:51 PM »

1-7/16" works

Mr.Stu · « **Reply #4 on:** November 29, 2006, 04:05:32 PM »

The 36mm one needs to be tightened to 175lb.ft or you'll wear out your wheel bearings in no time. The torque on that nut pre-loads the bearing.

I only mention it as not that many DIY torque wrenches go that high. I had to get one just for that job as none of the ones I already had were up to it.

Stu.

Mik · « **Reply #5 on:** November 29, 2006, 09:45:18 PM »

Quote from: "Mr.Stu"

The 36mm one needs to be tightened to 175lb.ft or you'll wear out your wheel bearings in no time. The torque on that nut pre-loads the bearing.

Stu.

Dear Mr Stu,

just so you dont mislead anyone else with this particular piece of well distributed bollocks, you can tighten the hub nut until the frickin shaft snaps off and it wont make the slightest bit of difference to bearing pre-load.
The official torque figure is indeed 175lbs but it IN NO WAY relates to the pre-load, lifespan or any other working condition of the hub bearing.

If you only think you know what your talking about then say as much or STFU.

Rant over (except for the other bollocks regarding Copperslip)

Regards

Mik

greggmo · « **Reply #6 on:** November 29, 2006, 11:50:45 PM »

Bubba · « **Reply #7 on:** November 30, 2006, 06:22:42 AM »

daggie · « **Reply #8 on:** November 30, 2006, 06:46:09 AM »

MK1 · « **Reply #9 on:** November 30, 2006, 11:59:57 AM »

Mik, bad day at the office or too much stella?

I thought you were such a polite young man!

Mik · « **Reply #10 on:** November 30, 2006, 08:37:23 PM »

Quote from: "Mark Barrs"

... or too much stella?

I don't understand the question

Mr.Stu · « **Reply #11 on:** December 04, 2006, 03:39:51 PM »

Mik,

Sorry to see you think I'm mis-informed. The bearing assembly is in two parts with the actual bearing running between them - stick a slide hammer on a nicely stuck one and you'll see the way they come apart. If you tighten it down to less than 175 ft.lbs the two halves don't come together tight enough and the bearing wears quicker due to slop.

If you over tighten it the two halves deform and the bearing runs tighter than it should which will also foul it up.

I don't really care if you believe me or not but I'd thought I'd take the time to explain it to you.

Stu.

Mik · « **Reply #12 on:** December 05, 2006, 07:30:48 PM »

OK, lets put this fecker to bed.

Ive been busy this morning in pursuit of enlightenment for all.
What you see here is a cutaway of a unit bearing assembly as fitted to your TJ, XJ, WJ etc etc and with it I shall attempt to show how utterly unimportant the textbook 175 lbft of torque is.

Just to clarify, I am not condoning the use of breaker bars with scaffolding pipe extensions (you know who you are!), merely making the point that in this instance the home mechanic need not worry about getting this right.

It has recently been argued that 175lbft of torque is critical to the performance and longevity of a unit bearing.
It can be seen from the cutaway that the inner section of the bearing is in two pieces. The largest part also forms the flange to which the wheel is bolted and the smaller part is a 'sleeve section' which when in place, holds the bearing together.
This 'sleeve section' is the crux of this whole argument. First of all, it is pressed into place under great force and is very difficult to remove. Secondly, it comes up against a shoulder section forming the inner part of the bearing assembly.
It can be seen that provided the bearing is assembled as supplied then the nut on the end could be finger tight and hold it together without problems.
It can also be seen that it would be neccessary to collapse this 'sleeve section' in order to affect bearing preload. I can only guess how much force would be neccessary to collapse this section. Several hundered tonnes? Even when it did yeald it would shatter rather than distort.

This next pic is a typical pinion crush sleeve. It is designed to crush in order to preload pinion bearings. This can take as much as 400lbft to crush. It is not made of bearing steel.

So, in tightening this hub nut (36mm), if you have a torque wrench use it, if you dont then wind it as tight as you can with your 1/2" drive whatever.
It will be just Dandy.

:wink:

greggmo · « **Reply #13 on:** December 05, 2006, 08:05:29 PM »

i thought i told ya not to mince yer words mik :lol: it is funny what you can make some people believe if you tell em offten enough. it is like the fact you must change the sump plug every time you do an oil change

Dave69 · « **Reply #14 on:** December 06, 2006, 07:47:11 AM »

on the topic of sump plugs, a new copper washer is a good idea and are dirt cheap. Nothing worse than a dripping sump plug. If the sump is ally a torque wrench is advised, can be stripped easily over a period of time if changed alot.

nice explanation and cross section of a hub

Mr.Stu · « **Reply #15 on:** December 07, 2006, 12:40:02 PM »

Wow Mik, you've put some work into this! Nicely done!

The crux of the matter is whether the pressed join between the two parts of the bearing assembly is sufficient to hold it together under working loads. Seeing as these parts have been separated by the combined efforts of a bit of rust and a slide hammer I think its a safe bet to say the joint needs a bit of help in the form of being clamped at the right pressure provided by torquing the nut to 175lb.ft.

Not tightening the nut enough will allow the two parts to be slowly hammered out of tolerance by the shock loads encountered by the bearing as you drive over pot-holes, kerbs, etc. and will allow the bearing to wear quicker - I'm not talking about catastrophic failure, just accelerated wear.

Now about comparing a crush sleeve with a unit bearing - apples and oranges spring to mind. Think about what happens when you torque down the nut past its designed load. Maybe you get an extra 1/4 turn on it. I'm not sure of the pitch of the thread on the shaft but the distance between the nut face and the stub face has been shortened. Some of that will be taken up by extra stretch in the shaft and some will be deformation of the unit bearing housing or just extra squeeze on the balls. This is going to be within the elastic limits of the parts unless you get the scaffold tube treatment mentioned before. With a crush sleeve you are pushing it past its elastic limit which takes alot more force. When the bearing starts rolling its going to be a bit tighter than it should and that will increase wear - again not catastrophic.

So in summary, while static over torquing or under torquing won't make much difference. When the bearing starts moving and suffering the loads associated with that the wear will increase if the torque is under/over that specified.

If you still don't believe me think about trying to remove a stubborn ball joint. Hammer all you want and you'll hardly budge it. Stick a ball joint press on it and if it really stuck it won't budge either. Stick the press on to apply a preload and then tap it with a hammer and it will budge.

Again, nice work sectioning the bearing - how long did it take you?

Stu.

greggmo · « **Reply #16 on:** December 07, 2006, 05:24:49 PM »

i dont knw about all the rest but i dont like the sound of the extra squeeze on the balls :shock:

Mik · « **Reply #17 on:** December 07, 2006, 05:33:10 PM »

I'm going for a little lie down

MK1 · « **Reply #18 on:** December 07, 2006, 05:34:02 PM »

Mik, did you sell the XJ?

Mr.Stu · « **Reply #19 on:** December 07, 2006, 07:36:45 PM »

I take it we're going to have to agree to disagree then Mik.

Stu.

Author Topic: Wheel Hub-Bearing Bolt - Socket Size? (Read 6357 times)

lizardland

lizardland

Toastie

Mr.Stu

Mik

MK1

Mik

Mr.Stu

Mik

Mr.Stu

Mik

MK1

Mr.Stu