rear hub leaks

[muttlee]

hello all
Been having trouble with my rear hub leaking, first time i replaced oil seal for it to fail almost straight away, so now thinking that layshaft o ring had failed i stripped engine and replaced oring and oil seal for it yes you guessed it got home today with no back break.could it be posible for the hub bearing to fail and allow oil throught?? it's a mb racetour bearing and only done ruffly 500 miles layshaft i had from another block that i used for a few year no probs

Cheers for any info

Lee

[rosscla]

I've just ruined two sets of brake shoes in similar circumstances. First time the oil definitely came from a leak on the neutral switch on the top of the casing and through the hole for the (missing) rubber inspection grommet.

Second time It was definitely the seal. Left for a couple of days I could see a drop of oil at the bottom of the plate. When I took it out the spring was round the bearing. I've fitted a new seal and left it for a a couple of days and no sign of weeping, so I've fitted another set of new shoes and will take it out for a good run tomorrow and see how it goes.

Someone did also suggest that you can get cracks around the studs on the retaining plate and the bearing housing. Might be worth a closer inspection there. Perhaps you could heat the area with a heat gone to see if you can track any weeping.

[Warkton Tornado No.1]

There have been reports of the MB rear hub bearing failing because the cage can pop out.

I have gone so far as to remove them from engines because I believe there is a serious safety issue in the fact that the cage can not only become dislodged, allowing the balls to go where they will, but IMHO there is the very real risk of the cage melting in adverse circumstances, therefore allowing failure.

(Moulded cages are fine where there is no safety issue, such as the flywheel side crank bearing. In that instance, the reason such cages find favour is that the design contributes to a higher rating, because more, or larger, rollers can be fitted in the 'space' as the result of not having two piece, normally metal, cages. In any case, were a flywheel side crank bearing to fail, causing a top end blow up, the clutch would allow the rider to maintain control, which is not possible if a rear hub bearing fails)

[rosscla]

Having had the cage come out of one I was building and reading some of the comments from others I will be stripping that one out again.

I think they've stopped using the plastic cage now though.