The New And Improved Unofficial R65 Forum V2

Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: DeeG on September 01, 2018, 12:50:17 AM

Title: Final drive maintenance
Post by: DeeG on September 01, 2018, 12:50:17 AM
How much of a chore is it to crack open the final drive and inspect the bearings?  I'm concerned about the condition of the bearings based on what my swing arm and rear wheel bearings looked like.  And I noticed some blue sealant of sorts peeking out from under the housing cover. 

At the least (no damage to bearings) I would need a new gasket. 

#2 in the drawing.  Would I also need #3, the gasket ring?

Title: Re: Final drive maintenance
Post by: georgesgiralt on September 01, 2018, 02:23:00 AM
Hello,

Having my splines badly worn, I bought a second hand rear drive. It was so cover with muck and oil that I decided to crack it open and change all seals.
It is not a very difficult job if you have the tools to lock the input arbor while removing the nut. Do not forget to change the seal under the input pinion.
And the lip seal on the castellated big input nut.
Use a torch or a heater to heat the housing in order to have the needle bearing out. (there is a lip seal under it).
All in all I spend an enjoyable afternoon looking at that fine piece of work.
Hope this helps.
P.S. the needle bearing under the crown has two oil passages. They where to the crown on my drive. I've learn that you can put them in the other way...
Title: Re: Final drive maintenance
Post by: Tony Smith on September 01, 2018, 03:58:53 AM
Motobins sell a kit with  all gaskets and seals needed for somewhat less than the parts individually would cost.

If you need to replace the big output bearing, buy the same brand bearing and you may avoid having to re-shim it, at least that's how it worked out on the 2nd hand final drive I rebuilt recently.
Title: Re: Final drive maintenance
Post by: Bob_Roller on September 01, 2018, 06:48:26 PM
A little tip, the paper gasket between the cover and final drive case, it only goes on one way figure it out before you add any sealant to the gasket . ;)
Title: Re: Final drive maintenance
Post by: Tony Smith on September 01, 2018, 07:18:43 PM
Quote
A little tip, the paper gasket between the cover and final drive case, it only goes on one way figure it out before you add any sealant to the gasket . ;)

Yep it only goes on one way. BUT, do not use sealant on it, it is enough of a bastard to clean the mating surfaces (as you are shortly going to discover) without also having to scrape sealant off - this one, like a number of airhead gaskets, does not require sealant, what it does require is scrupulously clean mating surfaces.

Also, if you do find yourself in need of re-shimming, when you take a deep breath to buy a selection of shims (they are expensive little suckers), then buy a couple of extra gaskets as you will find that the process of torquing the cover and then removing it to inspect the bearing blue will quickly destroy the gasket.
Title: Re: Final drive maintenance
Post by: Bob_Roller on September 01, 2018, 08:05:46 PM
I work in the commercial aviation industry, found a material, parting compound, put it on the metal surfaces, then put sealant on a gasket .
When you take the parts apart, the sealant and gasket just peel off .
Title: Re: Final drive maintenance
Post by: Tony Smith on September 01, 2018, 11:00:44 PM
Sound great Bob, but why use anything when none is required?
Title: Re: Final drive maintenance
Post by: Carott on September 02, 2018, 11:44:37 AM
DeeG,

Unless you have some indication of a problem I would not open the final drive just to inspect it.
If the drained oil is free of metal particles, not brown in colour (water in oil), of a volume close to 250cc and there have not been any strange noises or substantial oil leaks, leave it alone.
The swingarm and wheel bearings are subject to more abuse as they do not give the owner any indication that the seals have failed unless the owner is inspecting them during regular maintenance.
The final drive bearings are inside a sealed oil bath and will give ample warning of seal failure before any damage to the bearings.

Brett
Title: Re: Final drive maintenance
Post by: mrclubike on September 02, 2018, 08:05:04 PM
Use the Quad rings instead of the standard O rings on the brake shaft
Way better and cheap
And i have heard to lower the fluid level a bit

A was hassled with a leaking brake shaft until i install the quad rings
Title: Re: Final drive maintenance
Post by: mrclubike on September 02, 2018, 08:47:41 PM
Here is the Mcmaster Carr page
https://www.mcmaster.com/#o-rings/=1efj2wd