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Author Topic: Final drive Seal  (Read 144 times)

Offline Adrian

  • Posts: 516
  • The Old Hairy Biker Sez...
Final drive Seal
« on: May 15, 2021, 03:43:50 AM »
Hi there brains trust - deleted the post - found a video 👍😉

« Last Edit: May 16, 2021, 05:14:24 AM by Adrian »
1984 R65 (860)

Offline georgesgiralt

  • Posts: 1265
  • I Love YaBB 2!
Re: Final drive Seal
« Reply #1 on: May 15, 2021, 06:57:48 AM »
Before dismantling anything, do you have the correct amount of oil in the drive ?
If I were you, I would check that first.... And check it is the correct oil (type and viscosity)
Just my 2

Offline Bob_Roller

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Re: Final drive Seal
« Reply #2 on: May 15, 2021, 08:17:25 AM »
Have you removed the rear wheel to confirm the final drive seal is leaking ??
My thought is the outside chance the rear brake cam seals may be leaking .
Have you checked the tightness of the bolts that hold the final drive cover on ??
If you find that the final drive seal is the issue, you may want to order the paper gasket that goes between the cover and the final drive, if it has sealant on it, it won't be reusable, also, if you have no idea when the brake cam seal were last replaced, may want to do this as well .
The paper gasket only goes on one way .
To get the rear cover off, use two of the bolts that hold the cover on, there are two threaded holes in the cover that don't match up with holes in the final drive, you put the bolts in these two holes after all of the bolts are removed and start tightening them alternate between the two and they will push the cover off .
'81 R65
'82 R65 LS ?
'84 R65 LS
'87 Moto Guzzi V65 Lario
'02 R1150R
Riding all year long since 1993 .
I'll give up my R65, when they pry my cold dead hands from the handlebars !!!!!

Offline georgesgiralt

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  • I Love YaBB 2!
Re: Final drive Seal
« Reply #3 on: May 15, 2021, 11:12:47 AM »
If you remove the cover, the paper gasket has to be renewed. The OEM gasket has some sort of glue from factory and it sticks very hard to one or both surfaces. You'll destroy it when removing the cover. And you have to remove the gasket remains on the cover and the rear drive housing. It is a nice task to practice your seldom used curses...

Offline Carott

  • Posts: 18
  • 1980 R45/N
Re: Final drive Seal
« Reply #4 on: May 15, 2021, 11:50:30 AM »
Just one more tip is to use the genuine BMW seal.
I tried to reseal a final drive from an R75/5 with generic double lip seals from a local supplier. I kept thinking my technique was bad and I must have nicked the seal but after the third try I got a genuine seal and the drip was gone.
Also make sure to clean the oil weep holes so that any future leaks stay off the brake shoes.

Offline Tony Smith

  • Posts: 2274
  • Graduate, Wallace and Gromit School of Engineering
Re: Final drive Seal
« Reply #5 on: May 21, 2021, 04:32:27 PM »
From the top.

Do not use sealants on any gasket in the final drive (or anywhere else on an R65 for that matter). When cleaning the sealant off surfaces that was put there by a previous owner you can amuse yourself by thinking up suitable inventive tortures for them - I do.

If any mating surfaces are damaged (by a Moronic Previous Owner "MPO") dress them with an oilstone. If you are unable to recover the sealing surface a th an oil stone, then and only then, use the most minimal quantity of a non-hardening sealant such as Hylomar.

Never put sealant on the final drive to swingarm gasket, the gasket thickness precisely sets the alignment. Whilst on this topic, on reassembly insert the axle so that it holds the FD in alignment whilst you torque the nuts down.

To remove the inner cover insert two 5mm bolts in the two unused holes and after heating the cover a th a flame or heat gun, wind them out evenly to gift off the cover

Using a stud remover, or locked nuts, remove the 8mm studs to facilitate removal of the old gasket.

Use a beer can with the top cut off to protect the seal from the final drive splines.

When fitting a new seal, remember that the open side of the seal goes towards the oil to be contained. Ask me what happens if you get it wrong.

Heat the cover when you put it on - it will just drop on. Make sure the shims are correctly in place, findi g them on your bench when tidying up is very, very annoying (again, just ask me).

If you plan to change bearings, do you have a depth micrometers and a supply of shims? It is not a simple matter of just putting in the old shims.

To replace the outrigger bearing seal you need a puller. If your FD has the older needle roller bearing go carefully, they are expensive.

To replace the input seal you need two special tools, firstly to remove the lock nut and the second to remove and replace the seal carrier.
1978 R100RS| 1981 R100RS (JPS) | 1984 R65 | 1992 KLE500 | 2002 R1150GSA |