Hub stake nuts:Why so tight??

DIFFLOCK66 · Jan 8, 2014

Haynes says to torque these guys to 360 lb/ft. Over 3 times tighter than a wheel nut! Why so astronomically high a value?

Most Landy engines don't get close to outputting that amount of torque (Doc Evil's big block V8 excepted) :wtf:

Looking at the install, all the nut does is secure the halfshaft to the inner (rotating) part of the hub. The halfshaft uses splines to transmit the drive to the hub, not friction!! The nut will not stop the halfshaft and wheel from parting company with the axle - if the inner hub separates from the outer, static part then that shaft's on its way out. Only the brake caliper would hinder the process

The hub assembly is held on the axle by 4 relatively beefy bolts which only require 74 lb/ft each. If they snap, it's game over again

Vanmancan · Jan 8, 2014

Yeh I did one before Xmas and had to ring round all my m8s to see who had a big enough torque wrench . Guess that's why you can't use the same nut .and have to fit with a new one after all the torque going on it

DIFFLOCK66 · Jan 8, 2014

Vanmancan said:
Guess that's why you can't use the same nut

Can't you?

My front hub is still going strong.... it never came with a new nut and at the time of doing the job I hadn't known about it plus there was nowhere open in the evening. Plus the amount of wobble scared my experienced colleague...so on the new hub went

All it does is hold the halfshaft steady :frown:

Vanmancan · Jan 8, 2014

DIFFLOCK66 said:
Can't you? My front hub is still going strong.... it never came with a new nut and at the time of doing the job I hadn't known about it plus there was nowhere open in the evening. Plus the amount of wobble scared my experienced colleague...so on the new hub went

All it does is hold the halfshaft steady :frown:

I was just following what it said in rave . Couldn't see nothing wrong with using it again I even kept the old nut .look good to me still. It's more than Likely just over kill from LR

listerdiesel · Jan 8, 2014

DIFFLOCK66 said:
Haynes says to torque these guys to 360 lb/ft. Over 3 times tighter than a wheel nut!

Yes, but you've got 5 wheel nuts per wheel on a PCD that is about 6" or so, the drive shaft is retained by a single nut and it can take very high shock loads, the tightness is to keep the thread and shaft end in tension and the hub in compression so no movement between the two is possible.

Haven't seen any coming off or coming loose, so it must work.

You don't re-use self-locking nuts in critical apoplications.

Peter

jamesmartin · Jan 8, 2014

you can use them again and they are so tight as cv shaft is tough material nuts are held by stretch as above but torque wrench isnt necessary

nrgserv · Jan 8, 2014

DIFFLOCK66 said:
Why so astronomically high a value?

to sort the men from the boys

listerdiesel · Jan 8, 2014

I've always used the torque wrench on mine, but then I do have a 3/4" drive that goes to 450+ ft pounds.

Ex Scania truck mechanic

Peter

DIFFLOCK66 · Jan 9, 2014

nrgserv said:
to sort the men from the boys

OOOH! Harsh... but fair

DIFFLOCK66 · Jan 9, 2014

listerdiesel said:
so no movement between the two is possible

Ah... so in a way, it takes out slop between the halfshaft splines and the hub not that there's much to begin with.

listerdiesel · Jan 9, 2014

The trouble then is that the shaft and hub rust together....

Peter

JordanTD5 · Jan 9, 2014

It's that tight because it sets the pre-load on the two taper-roller wheel bearings.

jamesmartin · Jan 9, 2014

JordanTD5 said:
It's that tight because it sets the pre-load on the two taper-roller wheel bearings.

no it doesnt thats done by fixed spacer as part of bearing,though it does stop bearing falling apart

JordanTD5 · Jan 9, 2014

jamesmartin said:
no it doesnt thats done by fixed spacer as part of bearing,though it does stop bearing falling apart

But what does the spacer act against until the two bearings are sandwiched between the hub and the half shaft?

jamesmartin · Jan 9, 2014

JordanTD5 said:
But what does the spacer act against until the two bearings are sandwiched between the hub and the half shaft?

bearing is built as a unit without a shaft holding it together the bearing would come apart but the torque doesnt effect the bearing preload

JordanTD5 · Jan 9, 2014

Where is this spacer you speak of? between the two inner races?

jamesmartin · Jan 9, 2014

JordanTD5 said:
Where is this spacer you speak of? between the two inner races?

its a while since i striped a disco hub, but sometimes between the 2 bearings sometimes its just the bearings as such

JordanTD5 · Jan 9, 2014

JordanTD5 said:
Where is this spacer you speak of? between the two inner races?

jamesmartin said:

its a while since i striped a disco hub, but sometimes between the 2 bearings sometimes its just the bearings as such

Click to expand...

I haven't opened up a discovery hub but if its anything like other wheel bearings I've worked on it will look like this (Google image not mine).

Not you James but for any layman reading this. Wheel bearings almost always have two apposed tapered bearings so that they can deal with axial loads (horizontal during cornering etc...) as well as radial loads (weight of the car verticaly). The bearings have to be tightened againced each other to work, too loose and there will be slack in the system, too tight and they will not turn freely. This is the preload.

I imagine the spacer your talking about James will be between the two inner races of the bearing and set the minimum gap between the two, This will in effect set how tight the bearings can get together (max pre-load). They will however be loose until they are sandwiched between the lip on the hub and the mating face of the CV joint.

The torque on the hub nut is high because this is the torque required to press the bearings together and doing so sets the preload.

nrgserv · Jan 9, 2014

JordanTD5 said:
I haven't opened up a discovery hub but if its anything like other wheel bearings I've worked on it will look like this (Google image not mine).

Not you James but for any layman reading this. Wheel bearings almost always have two apposed tapered bearings so that they can deal with axial loads (horizontal during cornering etc...) as well as radial loads (weight of the car verticaly). The bearings have to be tightened againced each other to work, too loose and there will be slack in the system, too tight and they will not turn freely. This is the preload.

I imagine the spacer your talking about James will be between the two inner races of the bearing and set the minimum gap between the two, This will in effect set how tight the bearings can get together (max pre-load). They will however be loose until they are sandwiched between the lip on the hub and the mating face of the CV joint.

The torque on the hub nut is high because this is the torque required to press the bearings together and doing so sets the preload.

its a solid lump thru the centre, so theres nowt to nip up bearing wise.

JordanTD5 · Jan 9, 2014

nrgserv said:
its a solid lump thru the centre, so theres nowt to nip up bearing wise.

Really? On a Discovery 2? Any pictures? I cant find any without the hub already pressed through the center as it comes as an assembled unit.

I'd be VERY surprised if the bearing didn't look much the same as this discovery 3 item when on its own.

Hub stake nuts:Why so tight??

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