Back Axle Q&As

Replacing rear hub oil seals

Question:-

Please if you could advise me again. I noticed oil on the inside of the o/s rear wheel so decided best to examine the brake linings for contamination. So I removed the hub and yes, the linings have oil on them which I have cleaned off with petrol as only about one third worn and looking good for further use. I can purchase the rear hub oil seal and collar from the Octagon Club but am bemused as to how to remove the existing oil seal. Is it a case of prising it from its housing ? Presumably it is best to replace both the seal and collar at the same time when combating an oil leak ?

Answer:-

Simply remove the brake drum first, then the brake shoes. Then undo the four nuts and bolts that secure the back-plate to the axle case end. CAREFULLY lift the brake back plate away from the axle, it will move enough to be able to see the seal case. Support the plate on some wooden blocks. You will find the oil seal is in its own casing, pull it away from its gasket and it simply presses out. I doubt very much if the tapered collar will need renewing, they last for centuries. Press in the new seal, and after cleaning up all the faces make new gaskets for the casing and backplate, refit it all remembering to put a little oil on the collar for the seal to spin on (a dry seal will not last very long). Ensure you tighten up the ‘big nut’ on the half-shaft tight, or it will ‘chatter’ and ruin the splines.

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Rebuilding Differential

QUESTION;- I’m thinking of rebuilding my Y’s rear axle, it’s a bit noisy and has an oil leak on the diff.

ANSWER;- To change the diff nose seal on a YA/YT axle is easy, once you have undone the big nut holding on the prop-shaft flange. BUT to rebuild the axle is a very, very specialist job indeed, requiring the ability to ‘blue’ gears to check their meshing and possibly lapping-in the crown and pinion gears. Unless this chap has some excellent and vast experience of mechanical engineering, he will only ruin the axle!!!!! (If it is a YB axle that is certainly a specialist’s job and not for the amateur) The noise no doubt comes from the ball bearings on the diff carrier being worn and these are not too difficult the renew BUT we are up against that ‘correct meshing’ problem again. The taper-roller bearings on the pinion require pre-loading and AGAIN that meshing problem. Get the meshing of the pinion and crown wheel just out a tiny, tiny bit will have an axle that will howl loudly all the time as well as running hot due to the gears ‘sliding’ over each other and not ‘rolling’. It may well be cheaper in the long run to buy a second-hand differential unit in good condition.

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Oil leak from dip stick on rear axle

QUESTION;- I was wondering if there is a mechanism in the club to ask for technical advice regarding my YA. I have an oil leak from the  dip stick on the rear axle. When I’ve done a few miles oil runs down the down the axle from the dip stick. I have changed  the oil and refilled it with one and a half pints of the recommended 140 grade. The dip stick seems to be seated correctly  but I’m at a loss as what’s causing this. I can keep topping it up but I was just wondering if anybody had the same  problem. I’ve checked various websites and one suggested just using one pint of oil in the axle, but I’m nervous about that  approach.

ANSWER;- The rear axle dip-stick should have a felt washer directly under its head to seal the hole. It should (and must be) a very good tight fit in the filler plug as well. If the hole is worn have it machined out and a brass collar pressed in by a workshop. Are you sure its the axle dip stick that leaks? The seal in the diff-nose can leak and its oil blow back over the axle casing, looking like the dip stick leaks. Also the engine itself often leaks from the rear crankshaft scroll-seal, drips from the drain hole in the bell-housing, and again blows back over the axle case.