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hub nuts keep comming loose???

Posted: Mon Aug 18, 2008 6:36 pm
by subie_1st_timer
i had to change out the front driveshafts in the brumby, and ever since been having issues with the hub nuts continually comming loose.

ive always done them under the advice you do them up tight, back them off a touch and fit the split pin. Now this hasnt worked and ive had to resort to doing them up really tight, replace a split pin each time but within maybe a couple of weeks, knocking sounds comes back and the nuts are loose, to the extent the other day it had shattered the split pin

any advice here as is getting a little concerning. cheers

p.s the wheel bearings have been replaced so the knocking isnt from them, its from the loose hub

Posted: Mon Aug 18, 2008 7:56 pm
by AlpineRaven
Does the spilt pins cut themselves off? It shouldnt happen.. you'll need to do them very tight.
Cheers
AP

Posted: Mon Aug 18, 2008 8:06 pm
by Outback bloke
Never back them off to get the split pin in. Always tighten more to fit the pin. I think the factory tension is about 172NM. Bloody tight. Get a bit of pipe about 1 -1.5 metres long and put it on the end of a big breaker bar and socket. Then stand on the bar to tighten.

Another point worth noting is that if your cone washer is worn then they will not stay tight either. You can buy new cone washers for about $9 each.

Posted: Mon Aug 18, 2008 9:10 pm
by AndrewT
Be careful when standing on the breaker bar too, while you need to do them up very very tight, you can do them too tight aswell - I stripped the thread on the outer CV cup once doing that. Might be worth using a torque wrench if you have one that goes up that far.

Posted: Mon Aug 18, 2008 9:20 pm
by subie_1st_timer
guess im just shocked as to how tight i gotta do these buggers. Ill go grab some new split pins and redo them both again... many thanks

Posted: Mon Aug 18, 2008 11:27 pm
by CPOCSM
Yepp they are bloody tight little buggers...it is the same to get them off too - best to tighten a smidge first then loosen. I just did the rears in the L and nearly did a pooper valve. I then tackles a mini first motion shaft nut - 200ft/lb!! - had 2 mates sitting on my bench with the box underneath the bench and a sampson bar 4 feet long.

A few beers also helps!!

Hooroo

Posted: Tue Aug 19, 2008 9:18 pm
by Matatak
Make sure the washer is the right way round.

Outside edge should taper out i think

Posted: Tue Aug 19, 2008 9:42 pm
by AndrewT
Matatak wrote: Outside edge should taper out i think
correct
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Posted: Wed Aug 20, 2008 1:58 pm
by RSR 555
Brett aka Outback Bloke is right on the money... buy yourself a new taper washer. Another point to make sure of, is that where the taper washer fits to the splined hud, make sure there is no damage. This will ensure the new taper waser has a snugg fit. If you do this, you will only need to tighten the CV nut to Subaru Specs.

Posted: Wed Aug 20, 2008 6:13 pm
by raynman
A torque wrench is your friend. I know they are expensive, but maybe you can borrow one of someone or assemble and get a local mechanic to set the torque. We have found if you don't torque them up properly you can have the following happen:

Hub nut come loose (obviously)
Damage the hub assembly and driveshaft
Brake pad knockoff (and consequent big accident - no brake pedal)

Posted: Thu Aug 21, 2008 3:58 pm
by subybrumby
Outback bloke is right on the money here, I had a lot of trouble with this on my 91 brumby and eventually bought the new cone washer and matching flat washer for each side. I have had no further problems but yes they must be super tight.!!!! Flat washer has a paint spot that goes on the outside. And no, don't back the nut off..I know what you're thinking that that is how we do taper bearings on trailers. That is because on a trailer taper stub axle you are setting the preload on the bearing and if it is too tight you will collapse the bearing from overheating.

But these brumby babies need for that nut to be a lot tighter than we would normally be used to. There are spacer washers between the two bearings that hold that preload. I have been to two local CV specialists in Toowoomba and they agree. And don't forget your back axles, same applies.