Leaking rear axle hub [BT7] following instalation of new seal!

[fishyboy]

Hi all,
A few weeks ago my local garage replaced the seal on the O/S rear axle which was weeping slowly. When I took the wheel and drum off today everywhere was covered in oil from a major leak. Previously the garage replaced the oil seal, bearing, bearing spacer, hub lock washer and the paper gasket. There is no O-ring on this model.

Does anybody have any ideas what might have gone wrong?

Phil

 

[Bob_Spidell]

Just a SWAG: You mentioned the shop replaced the bearing spacer; why? If the shop put in a bearing spacer that is too thick the paper gasket can't seal. A different, but related, known issue is paper gaskets that are too thick, which prevents the necessary force--dunno off the top of my head what does this--from being applied to the spacer which allows the bearing to spin in its journal.

 

[steveg]

The bearing may have spun and eaten the seal. Check the seal.

You might want to have someone else do the work next time to avoid a re-run.

Because of the thick-paper issue, it might be better to just seal the flange with silicone.

 

[bob hughes]

Steve/Fishboy

I had to scrape the silicone off my BJ7 as it had failed as a gasket - put the paper gasket and O ring in - perfecto.

Just had time to examine the drawings in the SC Parts catalogue, similar to the Moss catalogue, and it would appear that the rubber O ring should be present on all models BN2- Bj8. I am no expert but are you sure that there should not be an O ring present?


Bob

 

[steveg]

Steve

I had to scrape the silicone off my car as it had failed as a gasket - put the paper gasket and O ring in - perfecto.



Bob

Bob,
Others have had success with the silicone. The o-ring does the heavy lifting. Phil doesn't have the o-ring so he should use the silicone as the paper by itself isn't good enough.

The paper gaskets compress down to about .010" which is too thick to clamp the bearing, which requires around .004". If the bearing isn't properly clamped it will eventually spin and eat the seal.

Also see this previous thread:
https://www.britishcarforum.com/bcf/showthread.php?99903-Learned-something-about-rear-axle-seal

 

[John Turney]

I am surprised there is no O-ring.

 

[steveg]

According to the Moss catalog the o-ring is found on all axles from the BN4 on. Maybe Phil has a BN2 axle on his BT7.

 

[fishyboy]

Hi all,
Having checked in the BT7 parts book, and from all your comments above, there should be a O-ring on the BT7. I have one on order and will check with the garage when the car goes back in next week.
Phil

 

[bob hughes]

Trust me I'm an Engineer :highly_amused:

Fishboy just check that you have the necessary projection on the spacer, it isn't rocket science , why don't you refit it all yourself.



Bob

 

[fishyboy]

Hi all,
Well the BT7 went back to the shop today to try cure the leak from the rear axle hub seal. The mechanic took the hub apart (much easier than I assumed). The half shaft looked fine and did not require sleeving. Secondly, we checked the hub oil seal which was in good shape and installed the correct way. It looked like the seal was doing its job correctly. The paper gasket,spacer and O-ring were all in place and looked fine. Everyone who looked at it assumed that the leak was past the O-ring and/or gasket, although but both looked fine. The mechanic took off the lock nut ans washer and replaced them. Then put on the O-ring with some black RTV sealant and installed a new paper gasket with a thin smear of RTV. Finlay, we re-installed the spacer and checked the projection which looked fine. The hub and drum were reinstalled a tightened down.

So nothing obvious as to what caused the leak. I shall inspect regular to see if the leak reoccurs.

Phil