Front hub under pressure

[Geoffrey F Miller]

My 1985 4-door Range Rover Classic has had the right hand (driver's side) front hub seals replaced four times over the last 19 years, due to leaks. In desperation it's now been filled with grease. I have always suspected that the problem has been due to a build-up of pressure within.

After a recent period of running, I removed the oil level plug and was greeted by a hiss of escaping air, like pulling the plug out of an airbed - sounded like several litres escaping!

Yes, the front axle breather is clear. No, it doesn't leak anywhere else (at least not from the front axle etc!)

Anyone else had this before? Anyone know what's going on?

[Landy-Andy]

Hi Geoffery,
I'm not convinced the breather is clear!
If the breather was open to breath, it would be impossible for pressure to build up (you can't blow up a balloon with a hole in it).
The breather has a little ball bearing in it, have you taken it off to see if you can you blow through it?
Maybe next time after you have been for a long run, slowly undo the breather to see if you get the same hiss of escaping air.If you do then the breather isn't opening.
I presume you have checked the breather tube is clear & unkinked all the way to the end?
Good luck,
Andy

[Geoffrey F Miller]

Andy, thanks for this
The breather on this age vehicle is of the newer pattern, with a banjo union onto the axle casing and a pipe up to the side of the engine compartment. It's definitley clear, been checked.
If it were blocked, there'd be pressure build up in the axle casing and left hand hub as well, which there isn't. It's just the one side hub.