And.......breathe

[Buller]

When changing the differental's oil and transfer box oil, I noticed the oil spat out of the filler plug of the rear diff when I took it out. Too much pressure build up I think to myself. When I looked at the diff breather valve on the top of the housing it was rusty and falling apart. More to the point it was blocked solid.
So I bought a genuine breather from Milner, (cheaper than Roughtrax), and fitted it as seen below. The important part of this story is that if the Diff builds up too much pressure that it can blow out seals. So for £10 incl P&P its better safe than sorry.
Thought I'd share this...

 

[chadr]

Glad to see you managed to remove your old one without issues - I've been trying to get my (I believe original) breather off for a while without success. I just can seem to get decent access to it!!

 

[Dave_S]

Also worthwhile extending them up into the chassis if you're planning any significant off roading (or driving flooded roads in winter).

 

[Buller]

Yes, I thought about extending it, and I will, just wanted to get it changed first.
Regards the access. You can get at it from behind the diff and over the back axle. Wire brush it off then soak it in release agent first. Get a deep 14mm socket and undo it. Its easy as its on a tapered thread, similar to a pipe BSP pipe thread. Using a spanner isn't easy due to the access as you said CHADr, but doable.
Cheers

 

[chadr]

Thanks - I'll look for a 14mm deep socket in my set and give it a go....

 

[chadr]

Thanks again for the tip re: access and deep socket - eventually managed to remove mine but needed to break out the "freeze and release" spray. After that, it almost seemed like it had only been tightened by hand!

Put the old one back in for now, until the new one arrives.

 

[AdventureWagon]

I gotta check mine next service! Got to get the correct socket and somehow remove the buggered front diff plug first!

 

[Buller]

Ooo, thats a difficult one. The front diff fill plug is a swine to get at. I took of both skid plates to make it easier. The fill is a 10mm and drain is a 12mm hex socket. I got mine from Screwfix, £10 for a set and decent quality. Use a short breaker bar, it'll reduce the chance of problems.
I was fortunate all the diff and transfer box plugs came out ok. I sprayed them in Plusgas release first.
Another tip, use a 15/16 inch socket for the rear diff and transfer box plugs. Its slightly smaller that the 24mm suggested and a better fit.
What front diff plug can't you get out?

 

[Shayne]

Worst case scenario some have welded a nut onto buggered plugs just to get it out .

 

[MODVRS]

I'm in the weld-a-bolt-on club. It snapped off but the plug still came out with Mole grips on the weld blob.

 

[chadr]

Just curious but when I finally managed to get my breather off, I poked a piece of wire gently into the hole and it hit something solid almost immediately - pretty much at the same depth as the breather plug.

I was under the impression that the breather would vent the diff case directly - so was expecting the wire to go in at least 10mm or so into the case before hitting the internals.

Is there a baffle of some sort or similar protecting the breather outlet.

Obviously because of the location, looking into it is not an option unless you have a scope...

 

[Chas]

A one way valve to let air out but not let water in?

 

[Chris]

No it's just a hole tapped into the casing. It's not that clever.

 

[chadr]

I wonder what the wire hit then? It was literally at the same depth that the threaded part of the breather would reach internally. So far too close to the inside of the casing to be the diff it self.

 

[Chris]

Well could be crud or perhaps just the diff. It's actually a pretty tight fit in there. Can't recall if the bore is perfectly straight or if there's a bend. I'd say that would be over engineered if it was. Possibly worth just poking it harder. I had my diff out at the time and I ran a drill down it to clear it out a bit.

 

[Buller]

Guess if you have the time is to drive it then take out the filler plug and see if the oil spits out like mine did. If it does then pressure is still building up, if not then its doing its job ??

 

[chadr]

Not the best picture but you can hopefully see what I'm talking about - there is something solid at the bottom of the breather hole. I'm not sure if it's the diff as it seems far too close to the case - there's hardly any "gap" if any.

Edit : this was nagging at me so much so, that I've just ordered a cheap USB endoscope from Amazon. The camera is only 5.5mm so should be able to get a look inside......

Hope it doesn't become a case of curiosity killed my cat diff....

 

[Beastrider]

Hi Chadr - did you ever resolve what was at the bottom of the axle breather hole?
Also, I have been thinking about a cheap usb camera - would you recommend the one you bought?

 

[chadr]

No, I never did find out. The usb camera was a bit sh*t - though perhaps I was expecting too much for the price. It simply couldn't focus close enough (<15mm) to get a clear pic. If the focal distance was greater than say 30mm, it would probably have coped.

I fitted the new breather and it hasn't made much difference - I still have a very small leak from around the bracket where the handbrake cable guide attaches to the rear diff housing. Probably need to grind it back a tad and apply some more metal filler...

When I attempt that bodge repair, I'll take the breather out again and recheck the hole - it may just have been the position of the internals.

 

[Lancashire Cruiser]

I’m surprised the breather is steel. Land Rover, certainly the earlier ones, are brass and easy to remove.