ARB Problem

[Wingnut]

I fitted an ARB RD56 into a 200/300 Discovery (on the change over between the two models - hence the fine splines on the half shafts) several years ago. The unit has done approx. 40-50,000 mls.with no problems at all, despite the use it has had.

I recently bought a Td5 and eventually got around to changing the Diff. from one car to another. While I had it out of the vehicle I put new O rings in the seal housing although they had never leaked.

While we were up at the Scottish Hill Rally and using the ARB, the compressors started to cut in. This was not happening all the time the vehicle was moving, and not at all when it was stationary, leading me to believe the leak was not in the pipe work but in the Diff. itself. ( by this time the new seals had only done approx. 3,000 mls.)

I have finally got round to pulling the Diff. out to see what the problem was and to replace the O rings. The Seal Housing should be held firmly in place by the retaining clip but this is not the case. When the crown wheel was rolled backwards and forwards the seal housing was also moving by about 4-5mm. in a circular motion and also lifting off the bearing adjusting nut by about 2mm. so creating a "wobble" when the Diff. was rocked to and fro, hence the failure of the seals and the air leak.

I bent the legs of the retaining clip in a little and this has stopped the seal housing lifting but not rotating. After some thought I built up the bottom of the bearing adjusting nut locking tab with weld and profiled it to fit the shape in the seal housing and this seems to have stopped the rotation in the seal housing.

Anybody have any ideas what else I could have done to stop the seal housing moving and have I created problems for myself in the future ??? All ideas gratefully received.

Sorry for the ramble,

Peter

[Jon White]

I've heard a few people say that the new clip on affair for the air housing is cr@p! Both mine are the older type that bolts on with 3 socket cap screws. It might be worth seeing if you can convert back to the older type housing.

Jon

[ashtrans]

I fitted an ARB RD56 into a 200/300 Discovery (on the change over between the two models - hence the fine splines on the half shafts) several years ago. The unit has done approx. 40-50,000 mls.with no problems at all, despite the use it has had.

I recently bought a Td5 and eventually got around to changing the Diff. from one car to another. While I had it out of the vehicle I put new O rings in the seal housing although they had never leaked.

While we were up at the Scottish Hill Rally and using the ARB, the compressors started to cut in. This was not happening all the time the vehicle was moving, and not at all when it was stationary, leading me to believe the leak was not in the pipe work but in the Diff. itself. ( by this time the new seals had only done approx. 3,000 mls.)

I have finally got round to pulling the Diff. out to see what the problem was and to replace the O rings. The Seal Housing should be held firmly in place by the retaining clip but this is not the case. When the crown wheel was rolled backwards and forwards the seal housing was also moving by about 4-5mm. in a circular motion and also lifting off the bearing adjusting nut by about 2mm. so creating a "wobble" when the Diff. was rocked to and fro, hence the failure of the seals and the air leak.

I bent the legs of the retaining clip in a little and this has stopped the seal housing lifting but not rotating. After some thought I built up the bottom of the bearing adjusting nut locking tab with weld and profiled it to fit the shape in the seal housing and this seems to have stopped the rotation in the seal housing.

Anybody have any ideas what else I could have done to stop the seal housing moving and have I created problems for myself in the future ??? All ideas gratefully received.

Sorry for the ramble,

Peter

Hi this is a problem with the spring retaining clip, the idea is good ie it allows the seal housing to self center. But as you note can cause other problems. I have seen a few of these recently and in all cases caused by the retaining plate or roll pin catching on the seal housing. We now drill the cap M8 and after setting the backlash /preload dimple the adjuster nut fill the hole with loctite then insert a grub screw to lock the adjuster nut. this allows the seal ring to float freely and self center.

Hope this helps