Half shaft oil seal

[Albannach]

When I replaced my diff some weeks ago, the oil that I drained from it had water in it! So yes I would have thought the breather alows airflow both ways.

It only allows air out, it doesn't let anything in. If you have water in the diff, either the breather is gubbed, or there's a hole somewhere...

[biosurf]

It only allows air out, it doesn't let anything in. If you have water in the diff, either the breather is gubbed, or there's a hole somewhere...

So with completely new breathers should you technically be able to submerge a hot diff with no problem?

[blackpoolsparks]

Tony (Dieselboy)
Its not a difficult job and the dismantling / reassembly of the shaft out the differential can be done in the drive.
Take shaft out
Take new bearings to man with hydraulic press (he'll know what to do)
leave
wait
return and collect shaft with new bearing on
when replacing shaft , the seal you replace is just inside of the diff opening
when you buy the bearing kit, you'll see where it goes and what it looks like
bolt everything back,
bleed brakes
check oil level ( I usually just drain old oil out and renew)
and away you go...

[Albannach]

So with completely new breathers should you technically be able to submerge a hot diff with no problem?

Unless there is a leak somewhere else, yes.

[blackpoolsparks]

Unless there is a leak somewhere else, yes.

so why do i need an extended breather (out of the water)if i want to go under the water with my diff?

mind, ive never had a problem without one

[Albannach]

so why do i need an extended breather (out of the water)if i want to go under the water with my diff?.

No idea, I've never understood that one.

[Apache]

Unless there is a leak somewhere else, yes.

So, let me see if I've got this right...

Hot diff, air inside expands so gets out through the breather. Diff cools down but air cannot re-enter so diff is now under negative pressure until diff gets hot again?

Sounds odd...

Personally if I was in and out of water regularly, I'd fit extended breathers and not have the worry about whether my breather is blocked and forcing oil through seals or stuck open and letting in water.

[Albannach]

Hot diff, air inside expands so gets out through the breather. Diff cools down but air cannot re-enter so diff is now under negative pressure until diff gets hot again?

Yep, the breather is a one way valve, out only.

[Albannach]

I guess the extended breather thing is for protection when the breather its self fails.

[BioHazard]

Yep, the breather is a one way valve, out only.

No it breaths in and out hence you extend them to prevent water ingress when the diff cools in water

[Albannach]

No it breaths in and out hence you extend them to prevent water ingress when the diff cools in water

My brand new Roughtrax one that I fitted the other day will not sook, it only blows.

Think about it, if it breathes both ways, what's the point in having it? A hole would do.

[Apache]

You're right of course Andy, I just wonder about the neg pressure. If you have a dodgy wheel bearing or axle seal, its going to actually suck water in.

[BioHazard]

The breather is there to equalise the pressure ...... a one way valve would not do that

http://www.toyotaoffroad.com/Article...f_Breather.htm

[biosurf]

No it breaths in and out hence you extend them to prevent water ingress when the diff cools in water

So, let me see if I've got this right...

Hot diff, air inside expands so gets out through the breather. Diff cools down but air cannot re-enter so diff is now under negative pressure until diff gets hot again?

Sounds odd...

Personally if I was in and out of water regularly, I'd fit extended breathers and not have the worry about whether my breather is blocked and forcing oil through seals or stuck open and letting in water.

That's where my confusion is coming from. I thought that the idea of breathers was to allow the pressure to regulate otherwise as soon as you do a long journey the diff is going to be in a pretty serious vacuum and the seals could fail. When I got my new breathers I was surprised that the are one way. Yes they can't be competely open but I thought they would let air in slowly but seal if the pressure changed quickly (i.e. if a hot diff got dipped in colder water)

Weird.

[Albannach]

It's a one way valve, if it weren't it would be a hole.

My old truck had new breathers fitted, after a few days with the new breathers I took the plug out and it sooked air in.