Oil on rear brake. R80ST

[jimish]

Appears to be coming from 6 o'clock in the bevel drive housing.

Has anybody changed the gasket PN 33 11 1 242 788 under the cover?
Is it an easy job?

Looks like there's just 8 bolts holding the cover on. Haynes manual says take it to a dealer!! but it does give a torque figure for the bolts. I think I will just check the torque loading on the bolts first.

it's only started leaking since I topped up the oil in the drive shaft so I'm also wondering if the oil seal twixt shaft and bevel drive has gone. Thinks : check oil level in shaft, if it's gone down then the seal has gone and that's going to be a bigger job.

All suggestions welcome guys.

 

[MickDB1]

Has the bike been parked up for a while
My rear end was leaking a tadge - ooooo eeerrr I was to start the process of getting all the seals etc. changed Someone on here advised me to run it for a few hundred miles and keep checking and wiping oil up
All seems Ok now lots of thousands of miles later Dont always be in a rush
with the spanners
Hope yer lucky

 

[jimish]

Just used the bike today after sitting for a week, did about 50 miles, but the other week I was out on it for a rally and did 600 odd miles, so I don't think it's because of lack of use.
I'm going to check tighten those bolts in the morning then clean up the back brake and ride it again, see what happens.

 

[Richard A]

Jimish, you write that the leak is coming from 6 o'clock in the bevel drive housing, so it's probably not what I'm about to say... however, it's not uncommon for the oil seals (o-rings) on the brake cam actuating shaft to gradually fail and maybe weep down the inside face of the bevel drive housing and start dripping at the bottom. Either way, it's probably worth replacing those seals if you're going to drain and replace the gasket.

I thought it odd that BMW would run the shaft through the bevel drive oil space (rather than a dry, greasable tunnel in the casing), but I suppose the upside is that the shaft is constantly lubricated.

 

[jimish]

Thanks Richard, I had the brake shaft out yesterday to check the o rings. I only restored the bike a couple of years ago and they were replaced then and didn't leak.

I reckon there was too much oil in either the drive shaft or the bevel drive (probably the bevel drive) because I filled them up according to the Haynes manual. Viz. 2mm above the hub gear for the drive shaft, and dribbling out of the level plug for the bevel drive.
Yesterday I drained out both oils (should have done them separately - doh!) and measured the quantity - 50 ml too much.
I've now refilled them with the quantities quoted in the manual - 150ml and 250ml, and stuck it all back together again. Time will tell . The next run probably.
I'll keep the forum posted.
Jim

 

[jimish]

Well, I went for a run yesterday, only 50 miles, and when I got back I whipped the back wheel off and lo and behold.................No oil!

BTW, the bolts on the cover were tight when I checked them.

So lets hope that's fixed it then.

Jim