Idiot proof wheel bearing preload????

[Knucklehead]

All,

Came across this procedure for torque setting the final preload on the front bearings.

Never really went down the fish scale/FSM route, tend to set mine more by 'feel' but I think this is the first time I have seen anybody state final torque settings.

If I read/understand this correctly they are suggesting the inner nut goes 55 Nm which I think is about 40 ft/lbs, though maths was never my strong point

Pretty sure that would be a lot higher than my touchy feely approach ends up at.

Anyhow thought would put it out there for a read if nothing else, not recommending folks follow it..

http://www.euro4x4parts.com/en/mechanics_4x4_brake_pads.html

 

[StarCruiser]

I followed Julian Voelker's method when I did mine as everyone seems to swear by it. Double checked it with the scales and all seemed ok. IIRC that reading was for settling everything down and was repeated a few times before finally setting hand tight or at something like 4Nm. Don't rely on my memory of this though.

 

[frank rabbets]

Vital to use the scales on the wheel stud. RM184E SA 20-21 refers. If the bearings are loose steering is a little vaguer and after turning tight corners the calliper pistons can be pushed up into the calliper so when you next use the brakes there is excessive pedal travel. If the bearings are too tight they get too hot and wear rapidly. I've seen them go BANG and disintegrate if extremely over tightened. Smoke appears first though.

Any wheel bearing work should be checked by driving 6 miles without using the brakes then stopping using engine braking. The hubs should be about 50 degrees C. No hotter.

Well I'm still alive anyway.

 

[chapel gate]

Ive allways used the haynes manual method which states torque settings for the front. The old chap does them by feel, but hes been doing it that way for 50 odd years so hes quite good at it now..

 

[Chris]

I prefer the scales method because it measures the actual pre load rather than the torque of the nut. With damage and dirt you could actually measure torque that it not actually applied against the bearing. Personally, I tighten the nut and do all the back and forth stuff to seat the bearing but slacken the nut back to to get the rotational pre load. In other words rather than keep nipping it up to get the pre load, I start tight and back off to get the pre load. Just my preference. No, I don't use a 6' scaffolding pole to do that. I don't tighten them till the hub stops turning before anyone writes in.

I have had some nuts that went almost solid only to find it was damaged thread on the stub axle. If I'd only used the torque wrench I wouldn't have known.

Also, leave the nuts on the outer drive flange when you try to get the cone nuts out. It stops them pinging into the flower bed.

 

[frank rabbets]

As Chris says it's the only way to directly measure the preload Total load - Free load = Correct load.

I've had similar sized wheel bearings on another car where you had to use the correct sized internal spacer before doing the nut up really tight. You kept going down in size in spacer until there was no play then used a spacer .0003" thinner. The preload was therefore only .0003 but the bearings were quite tight to turn. This illustrates how accurate it should be done.

 

[frank rabbets]

P.S. Should be .003" above. My edit doesn't work.

 

[Chris]

Bit like my Quad then frank. A spacer in between the inner and outer middle race other than there's no shimming there. All that worked out fine btw. Bearing snugged up nice

 

[frank rabbets]

Yes. These were tapered rollers like on the front 80 bearings and the spacer was .003" thinner than the measurement between the hub shoulders. I don't think you can or should preload ball bearings so you have to use a spacer with an identical measurement to that of the hub. Some spacers are tubes and crush up to give the right preload when a predetermined torque is applied to the nut.

Years ago a Renault garage changed my friends rear wheel bearings. In the FWM it said "A TORQUE WRENCH MUST BE USED". On the mway he noticed smoke for a mile or so and then a loud bang and lost control of the car. The bearings had exploded.

 

[Towpack]

Any wheel bearing work should be checked by driving 6 miles without using the brakes then stopping using engine braking. The hubs should be about 50 degrees C. No hotter.

Well I'm still alive anyway.

I checked mine this way after fitting new discs recently. Did a 12 mile run on the M1 at 50mph (roadworks with cameras!) and the highest temp was the driver's side at 39 deg C although it was a fairly cool day. The NS always runs 2-3 degrees cooler even though they where torqued to the same spec.

All the motorcycles I've ever come across use ball bearings and precise spacers in the wheels. I guess MC's can get away with ball instead of taper bearings as there's hardly any side loading on them while cornering etc.

 

[Dave2000]

There are many ways/ideas/thoughts on tightening wheel bearings, mine is with brake pads removed (or at least pistons pushed back) tightened whilst rotating the wheel, when difficult to turn I stop and back off, then repeat. Finally back off and tighten slowly until all movement at 6 and 12 has gone, fit lock tab and tighten outer nut. The outer nut may apply a touch more load but not enough to be of consequence. I have used this system on this type of wheel bearings for many years with no issues, I have never measured temps either. These are old style systems and I do not recall ever being sent out to measure hub temperatures.

The only time I have seen hub temperatures measured is when the ministry check for non operational brakes on whatever HGV I was driving at the time.

The real issue here is that a manufacturer cannot simply say 'tighten hand tight and they will be fine' because the manufacturing process calls for a consistent method that can be applied by all members of the workforce who happen to be working on that particular area of the car during assembly, after that it is down to the individual mechanic's experience to apply whatever method he has been taught or has learned from experience, and that is the important word here 'experience'.

And for what it's worth, I have a Max Ellery manual and IIRC the wheel bearing load for the 80 is stated as something like 40 ft/lbs and call it done!! If I had read that and followed the instructions WITHOUT applying my own experience there would undoubtedly have been damage.

regards

Dave

 

[Towpack]

There are many ways/ideas/thoughts on tightening wheel bearings, mine is with brake pads removed (or at least pistons pushed back) tightened whilst rotating the wheel, when difficult to turn I stop and back off, then repeat. Finally back off and tighten slowly until all movement at 6 and 12 has gone, fit lock tab and tighten outer nut. The outer nut may apply a touch more load but not enough to be of consequence. I have used this system on this type of wheel bearings for many years with no issues, I have never measured temps either. These are old style systems and I do not recall ever being sent out to measure hub temperatures.

The only time I have seen hub temperatures measured is when the ministry check for non operational brakes on whatever HGV I was driving at the time.

The real issue here is that a manufacturer cannot simply say 'tighten hand tight and they will be fine' because the manufacturing process calls for a consistent method that can be applied by all members of the workforce who happen to be working on that particular area of the car during assembly, after that it is down to the individual mechanic's experience to apply whatever method he has been taught or has learned from experience, and that is the important word here 'experience'.

And for what it's worth, I have a Max Ellery manual and IIRC the wheel bearing load for the 80 is stated as something like 40 ft/lbs and call it done!! If I had read that and followed the instructions WITHOUT applying my own experience there would undoubtedly have been damage.

regards

Dave

Agreed, the 'hand tighten' method is quite vague to say the least but when you say you stop "when difficult to turn" this also introduces a variable. Just how difficult is "difficult to turn"? It will probably vary from person to person. Using the scales method to measure the rotational torque required to turn the hub at least gives a definite preload value. JMO

 

[Dave2000]

Agreed, but the word here is 'experience', 40+ years of it.

regards

Dave

 

[Shayne]

Any tips for getting this snap ring back on when I’ve got no pliers and the shaft slips back inside when I try anything else - it’s driving me nuts !

And do you torque the outer locking nut , if so to what ?

 

[David]

Any tips for getting this snap ring back on when I’ve got no pliers and the shaft slips back inside when I try anything else - it’s driving me nuts !

View attachment 157425

And do you torque the outer locking nut , if so to what ?

The hole is threaded screw a bolt in it

 

[Shayne]

David you are a hero !

Wish I’d asked an hour ago but it’s on

 

[David]

David you are a hero !

View attachment 157426

Wish I’d asked an hour ago but it’s on

I have a pair of plyers like this, makes a lot of clips easy

 

[Shayne]

Me to but its kept someplace safe with all the 10mm sockets .

 

[Chris]

You can use a large socket and a washer to get the snap ring back on if you're are in the field. Use the bolt down the middle with another nut on the washer. Wind the nut down the bolt and the socket will push the snap ring over the end of the shaft.

 

[nielsc]

At first I did mine hand tight but I could not seem to get it right and sometimes they came loose ( I run 35s tough)
Then I found this method on Ih8mud and this worked a threat !

copy paste:
We would do the bearing preload rotate then tighten again, rotate. Then we would back off to the point that the nut was loose. Hand tighten, then check to see how much the washer would move back and forth with a screw driver. IF no movement then loosen, if real easy movement not tight enough. this was a trail and error until you got good at it. when it was just right you put the lock washer on then the lock nut and tighten to what ever the man spec's were. then check to see if you could move the washer with some force, not two handed force but some more force then it took with just the jam nut. Sound hazzy but works real well. I have been using this method for over 20 years (yea I am old, but big enough to wipp most) and it is what I use in the shop today. It takes a feel and it may take a couple of times doing it but will serve well. The way you would tell if it is too loose(before driving the truck) is with the tire and wheel on, with every thing on the ground and you shake the tire(from the top) back and forth and you have looseness, the bearing preload is not enough, do it over or you will have problems.