Torque setting of rear hub nut

[letemglow]

Hi inmates,

I'm rebuilding the rear axle of my BJ8. I have found all the required alignment and torque parameters of the differential but with the exception of the torque setting of the 2 3/16" hub nuts.

Can anyone help me out here?

Thanks a lot!

Cheers Dieter

 

[GregW]

There is a torque spec section in the Wiki, click HERE to get to it. Looks like the number you want is 55 ft/lbs. If anyone sees something missing, new numbers can be added. Oh, and welcome to the Forum Dieter.

 

[letemglow]

Thank you Greg. Great Forum here...

I think I need to more precisely describe. I meant to say the gigantic 2 3/16" hub nut that holds the hub bearing to the axle stub. Its torque must be quite substantial I's assume.

Cheers Dieter

 

[Bob_Spidell]

Hi Dieter ("inmates" - good one :wink: )

I've never seen a torque setting for that nut. I've always figured:

- the hub is an interference (press) fit--would almost hold itself without a nut
- since the nut is locked with a tab washer, it isn't going to turn so even if the hub tried to come off it would only increase the tension--hence torque--on the nut
- the nuts are opposite "handed"--like knockoffs--so, in theory, if they do turn in the direction of wheel rotation they tighten (this may not apply to early cars)
- even with the "special" socket, it's difficult to get a humongous amount of torque on the nut anyway (judging from what I've seen, most people tighten these with channel-lock pliers). I think I was able to get about 100+ ft-lbs using a proper socket.
- I don't think it's possible to over tighten, unless you manage to strip the threads--hopefully, on the nut--or round off the corners of the nut

I think you should just make sure the hub is pressed onto the axle housing until it's stopped at the end of the (smaller diameter) machined surface. Then, torque as best you can--using the correct socket if available--and secure it with the tab/locking washer.

The Healey rear-end is known as a "three-quarter floating," which I believe means that it's all but totally secured without depending on the axle. I've never heard of a Healey rear wheel coming off (doesn't mean it's never happened, of course).

Cheers,
Bob

 

[GregW]

Well, I looked through three manuals (they were all different) and didn't see the torque figure you are looking for. But as Bob says, the locking washer will help.

 

[Keoke]

Thank you Greg. Great Forum here...

I think I need to more precisely describe. I meant to say the gigantic 2 3/16" hub nut that holds the hub bearing to the axle stub. Its torque must be quite substantial I's assume.

Well how about 6.93 kg.m-

However, in this case the size of the nut does not influence the torque specification of the fastener.-- ---Keoke

Cheers Dieter

 

[letemglow]

Great replies, thanks mates.

From the info that Bob and Keoke gave I understand now that the hub bearing nut indeed doesn't need to hold a lot and thus only moderate torquing is needed. Will go with 50 ft-lbs. then. I have recently bought a proper 2-3/16" socket - cost a fortune - so tightening will be a cakewalk.

Cheers Dieter

 

[healeynut]

Great replies, thanks mates.

From the info that Bob and Keoke gave I understand now that the hub bearing nut indeed doesn't need to hold a lot and thus only moderate torquing is needed. Will go with 50 ft-lbs. then. I have recently bought a proper 2-3/16" socket - cost a fortune - so tightening will be a cakewalk.

Cheers Dieter

The main thing is this nut needs to be firm against the bearing, but it doesn't need to be over tightened because there's the lock washer to hold it. 50 ft-lbs is probably just fine...

 

[Bob_Spidell]

On this topic (sort of): I've wondered about the locking tab washers. Since they're (apparently) made of mild steel they will compress some under pressure. I wonder if some of the tension on the bolt/nut will be reduced as the metal compresses--partially defeating the purpose of torquing/tensioning the bolt/nut--or, is the metal fully compressed on tightening, so there's no problem?

 

[healeynut]

On this topic (sort of): I've wondered about the locking tab washers. Since they're (apparently) made of mild steel they will compress some under pressure. I wonder if some of the tension on the bolt/nut will be reduced as the metal compresses--partially defeating the purpose of torquing/tensioning the bolt/nut--or, is the metal fully compressed on tightening, so there's no problem?

Yes, probably. The main thing is this nut needs to be tight so that the hub isn't loose when you drive. If there's some compression, it really doesn't matter....

 

[Bob_Spidell]

I've wondered about these locking washers (mainly because it's hard/impossible to find some of them). I've never seen them used anywhere on aircraft--including engines--on which it's fairly important that things don't come apart. On aircraft, everything of importance--pretty much everything--is safety wired or cottered. I would prefer that critical fasteners be safety wired; I presume they used these locking tab washers because they were quicker and easier to use on an assembly line.

 

[Randy Forbes]

Well, for what it's worth (over thirty-five__>35__years of British car ownership) I've never had a locktab fail in service, nor fail to be secure upon removal for maintenance.

 

[healeynut]

I've wondered about these locking washers (mainly because it's hard/impossible to find some of them). I've never seen them used anywhere on aircraft--including engines--on which it's fairly important that things don't come apart. On aircraft, everything of importance--pretty much everything--is safety wired or cottered. I would prefer that critical fasteners be safety wired; I presume they used these locking tab washers because they were quicker and easier to use on an assembly line.

Have you ever tried to hammer out the locktab? The locktabs are pretty darn stiff!

 

[Bob_Spidell]

Guess I didn't make my point clearly. I don't have a problem with locktabs' holding ability, only that they aren't reusable (except some like for the rear hub nut, which can be used up to 8 times) and I can't find (some) replacements (at least not at the 'usual suspects'). One can of safety wire would last a shadetree mechanic a lifetime.

Still curious why they aren't used on aircraft--maybe just not enough things like driveshafts and hub nuts and, though it's trivial, safety wire is probably a bit lighter.

 

[andybj8]

Try this explanation of the same system in the MGA and make your own conclusions:

https://mgaguru.com/mgtech/rearaxle/ra102.htm

Its not in the Healey, Kenneth Ball Autobook, but I guess the MGa one came out later.

cheers Andy

 

[BlueRidge1]

In support of Andys post I had a post back in 11/16/06 concerning the 8 sided nut and torque specifications.
The post was number 214661 if anyone would like to reference it. The link that Andy posted is the same link that Dave Russell posted back in 06 and Dave supported the idea of a torque setting of 150 lbs. I do remember following that advise and also that I had to borrow a torque wrench from my brother because mine would not work on the left hand threaded nut.I also fabricated my own 8 sided socket on a milling machine which took me several hours to make. If anyone would like to use it pm me I can send it to you if you will send it back in a timely manner.

Bob

 

[healeynut]

To be honest, at that torque wrench setting you really don't need a torque wrench. Just put it on as tight as you possibly can, by hand.

 

[Randy Forbes]

In support of Andys post I had a post back in 11/16/06 concerning the 8 sided nut and torque specifications.
The post was number 214661 if anyone would like to reference it. The link that Andy posted is the same link that Dave Russell posted back in 06 and Dave supported the idea of a torque setting of 150 lbs. I do remember following that advise and also that I had to borrow a torque wrench from my brother because mine would not work on the left hand threaded nut.<span style="font-weight: bold">I also fabricated my own 8 sided socket on a milling machine which took me several hours to make.</span> If anyone would like to use it pm me I can send it to you if you will send it back in a timely manner.

Bob

C'mon, hours? I know, you're really just trying the "play up" the socket's value :wink:

Yours must be a lot prettier than mine, 'cause I didn't spend much time on it at all...

But I remember that thread, and likewise used 150# torque (though I might've only "pulled" 37-1/2 Lbs, with the assistance of a 4:1 multiplier).

 

[BlueRidge1]

Randy
The several hours could also be atributed to my lack of skills on the milling machine. I will post a picture when I get a chance to spend several more hours learning that process.

Bob

 

[healeynut]

Or you could just buy the tool from British Tool!