oil leak at the rear brake

[guyom]

Hi guys, I have to remove my rear tire and since i do that i've got a oil leak. So i remove again wheel, check and the leak looks to come from the brake arm which go trough the final drive shaft. Is there a o ring or some thing i can do or change... sealer ? thanks for time
G

[Bob_Roller]

There are two O-rings on the shaft .

[Bob_Roller]

[movedhere] Misc. Technical Discussion [move by] Bob_Roller.

[Barry]

The number of O rings varied as BMW struggled to make it work.

[Bob_Roller]

There  usually are additional grooves in the shaft, all three of my R65's have an additional 4 grooves but they are shallow and will not accept an o-ring .

[peteremc]

I experienced this problem recently following reassembly.

I did a foolish thing and thought "Yeah, those o-rings look fine" (I have 2) and put the shaft back in. I also checked how many o-rings there should be, because there were, certainly, a number of extra grooves in my shaft.

On test riding, I found I had oil neatly distributed all around the rear wheel. Not a nice feeling.

Small job to disassemble, took the shaft to the local bearing shop (with o-rings intact) just before closing time on Saturday lunchtime and they measured, located the correct o-rings and advised me that the cost was going to be a whole 60 cents.

I left them some beer money as well and had the bike back on the road in about 30 minutes. No sign of a leak since. Happy customer.

[Barry]

Rear brake shoes are not that cheap and it must be annoying if they have to be replaced because of oil contamination especially as they otherwise last a very long time. I still have the original shoes fitted. Out of curiosity how big is the opening between the pivot shaft and the main body of the final drive. Would it be impossible to seal it off and revert to a greased shaft like the early model.  I guess one way would be to bore it out and fit a sleeve.

[suecanada]

Well my old bugga boo problem...well I'll be a brake shaft oil leak thread!! As some of you guys probably know, for years I battled this oil leak. (I hated a dirty white rear wheel!) So I replaced all the o-rings with the proper BMW ones several times and made sure the o-rings only went into the square profiled grooves. Well after say 10 years of reoccurring leaking I bought a new brake cam actuating shaft from Motobins and for the first time I can go out to the Brrmm Closet, wipe my finger under the hub and NO OIL! Yes I am shouting and for a good happy reason!!

[suecanada]

Oh and one more point...the Motobins site lists the arm as for post 1985 R65's. But it fit and worked perfectly on my 1983 R65LS. Don't forget to order the right o-rings too. They will help you get it all right...good company and fast delivery. Around $45.00 CDN if I remember correctly. Sounds a lot but for my peace of mind...priceless!

[Bob_Roller]

Barry, there is just enough clearance between the final drive case and brake camshaft, to allow the O-rings to enter, you have to give it a slight tap with  a hammer of other suitable tool to get the shaft started .

I think one of our members has had the final drive case hole opened up and had an insert placed there, to eliminate the oil once and forever .

I think the member was marcmax that had this done .

[guyom]

hi guys thanks I tried to remove the arm... is there something to do specifically because i can not. I clean everything and obviously, want the arm is under tension : i have the oil leak. When the arm is not under tension : nothing. Anyway i would like to check the o ring. So if you have any comments to remove it ? Thanks

[Bob_Roller]

I don't know how far along you are, so I'll assume nothing has been done .

Remove the rear wheel, loosen the adjuster on the rod that moves the arm on the right side of the final drive, remove the arm on the shaft .

Mark it before you remove it, so you get it back on correctly .

Remove the brake shoes, then use a rubber, or plastic face hammer on the end of the shaftshaft where the arm was located .

A few taps is all it should take to get it removed .

[nhmaf]

Mine started leaking this year, after several years of no leaks.   I replaced the o-rings with BMW replacements (2), plus I also fit one in the small groove on the 'splined' end that protrudes out to engage the rear brake lever/rod (a felt "washer" goes there, and this ends up going under the felt washer).  That strategy worked fine with the previous leak/changes where it was leaking on that shaft opening inside the brake hub area and also outside on the rear brake lever attachment.

This latest time, it was again leaking from beneath the metal flat washer inside the brake hub area where the brake cam rod passes through the final drive cover.   This time, along with changing all the o rings and flat washer, I used a bit of permatex form a gasket on the back side of a new replacement flat washer in that location.   I've only put 50 miles on the bike since then, but no leaks yet.