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80 Series Front Diff Leak / Pressure Problem

Posted: Fri Mar 12, 2010 3:33 pm
by Surfin Alec
I need help to diagnose my front diff leaking problem.

Its a 97 80 series with a front air locker. The air locker allways spits diff oil out the solenoid when used and seems to seep even when not used.

The diff started to leak to the CV on the passenger side a few months ago and out the swivel housing etc etc. I knew the axel had a slight groove where the seal sits and I suspected the brass bush in the spindle might also be stuffed.

So I replaced the spindle (a new type with a needle bearing), replaced the axel seal, replaced the axel. Re-built the passenger side as good as new.

Then a couple weeks later, the f'n axel starts to leak again......
So I thought the diff might be getting pressurised?? I pulled the diff breather off (I have it extended to under the fire wall with the factory black box end attached). I cant say 100% but I am sure that I heard a slight pfft. I blew in the breather and whilst I could blow / suck it wasnt free flowing, but not that much more that with the breather end off and just the hose only.

So I have left the breather disconnected all together, now I am getting diff oil out the breather top and the axel leak appears to have slowed (I think it only just seep from what was in the CV allready).


What could be the cause of the diff oil to pressurise and leak out the diff breather???? And more so the axel seal when the breather is connected???

Any help very appreciated before I chuck it and get a Nissan. :cry:

Posted: Fri Mar 12, 2010 3:46 pm
by berad
A bit of oil out the solenoids for the air lockers is normal, not seeping out though.

Does the compressor cut in and out constantly when the front locker is on.

There shouldnt be that much pressure inside the housing to push oil up 1 metre, and definately not when there is nothing at the end of the hose, not enough to notice it. I just have 2 dollar carby fuel filters on the end of my diff breather lines, that way there is never an obstruction and dust etc cannot easily get in there.

Is this an onroad and offroad problem?

Constantly driving through puddles, mud etc will cause pressure build up as everything that was hot cools rapidly.

Posted: Fri Mar 12, 2010 3:57 pm
by Surfin Alec
The compressor only restarts occassioanlly, not a lot.

The oil is only comming out the breather with the hose disconnected, only a bare barb. Havent tried with hose only as yet.

A mate has suggested that the caliper may be rubbing and causing excessive heat??? Have to check that.

Cheers,
Alec

Posted: Fri Mar 12, 2010 9:41 pm
by fester2au
Alec, did you actually check the barb on the diff to see if it was patially blocked. From memory they are a pretty small internal opening so it wouldn't take much to partially block them.

Posted: Sat Mar 13, 2010 7:39 am
by Auto-Craft
oil will splash out the barb when running.

80 series had a small catch bottle on the breather becuase they would pump oil up the breather,.

Air lockers shouldnt leak air into the diff, or oil into the air line, and most times install is what causes the oil in the air line, its not a design fault, as many will claim.

Install it properly, and it wont happen.