Outer Limits 4x4 Board

My ARB is leaking inside the diff.

It pumps up & looses enough air that the compressor starts about every 5 seconds . It has gradually been getting worse.

QUESTION : What part normally leaks? Copper line had plenty of clearance so would it be the o-rings or something else?

I think it's time to fix this put it in the back & set up a new one in the HP front

If you think there was enough clearance on the ring gear then it will be the seals. They are only a few $$ from ARB. There is no sure way of telling if its seals or copper line without removing the centre.

Up until recently on new ARB lockers the "copper" line is actually Bundy tube . ie. copper plated steel.

Assuming an older type toyota diff as you havnt stated.

Leaks can be loose bulkhead fitting, worn or damaged "o" rings, leaking or loose seal housing.
99% of time "o" rings.
Obtainable from ARB or bearing distributor. (Viton)

Bazzle