Rear brake shoes

[darrylri]

Is it true that one must buy a complete kit, to replace the shoes?

I spent a couple hours yesterday cleaning the rear half of my free bike, after removing the rear wheel.  I remember now how I cursed those snowflake wheels when I owned my first R65, too.  

Anyway, the shoes were thin and there was dirty grease all over the inside of the drum; I think the PO had been too enthusiastic with it on the splines -- which are in great shape, so at least that part worked.  And the wheel bearings felt good, too.  But it took me two cans of brake cleaner to get all the dirt and grease out of the drum and off the final drive.  

Next jobs:  

• cleaning the front half
• disassembling the forks to install new seals and steering head bearings
• replacing the master cylinder

 

[Barry]

Is it true that one must buy a complete kit, to replace the shoes?

Not sure what you mean by a complete kit. The shoes are supplied on their own as far as I know. There are still one or two outfits that will reline your shoes but I suspect it would work out just as expensive.

BTW those shoes must have done some miles as they are reckoned to last a very long time.  

[montmil]

As brake shoes are manufactured as matched pairs for maximum braking efficiency, it would be false economy -both money and stopping performance- to replace only one shoe. The springs would make up a 'kit", I suppose.

If there's adequate brake lining meat remaining on the pair, have you considered boiling the shoes to remove contaminants? Also check the condition of the brake cam shaft 10x2 O-rings as a possible gear oil leak into the brake drum area.

Monte

[darrylri]

The bike has 169,000 miles on it, but I have no idea how old the shoes are.  However, they only have about 2mm of lining left, and I noticed before I disassembled it that the brake arm was well over center at rest.  

The kit includes the shoes, springs and another part that realoem doesn't list separately, but might be a cover for the spring coils.  (Whatever it is, I didn't see it on the shoes/springs I removed.)

Thanks for the hint about the O-rings, I will check it out.  I didn't suspect a seal leak because I have ridden the bike some and didn't notice any fresh oil.  Since it's up on the lift, it certainly won't hurt anything to drain and refill the final drive.

[Barry]

Motobins sell just the shoes (in pairs of course) for £27.50 which seems very reasonable. The springs are so strong I doubt they would have deteriorated much unless from severe corrosion. They also sell anti resonance rubbers which as you mention may be the other part of the kit but I think were not fitted as standard and may not be required.

Not sure what year your bike is. The early 78 - 80 models don't have or need O rings on the brake spindle but obviously still worth a clean and re-grease while the shoes are off.

[montmil]

...Not sure what year your bike is. The early 78 - 80 models don't have or need O rings on the brake spindle...

...Due to the shaft's passage through the final drive case being a sealed "tube" rather than the later models with an opening directly to the brake shaft from the drive case. BMW evidently thought the brake shaft would benefit from a continuous splash of 90wt gear oil. You know you need new O-rings when the drips fall off the bottom of the final drive case onto the rim and tire. Brakes also may not be as "superior" as before.

The O-ring grooves are milled with a flat-bottomed groove to permit the O-ring to expand and seal as the shaft is pushed through the gear case. Some models, varying by year, have two O-rings -as on my 1981 R65- while others may have four O-rings -as my 1983 R65. Some owners have had the brake shaft machined to accept additional O-rings. There are very shallow grooves on the shaft that are helpful milling locations.

And I finally gave up attempting to locally source the correct 10x2 mm rings. Nothing worked, either metrics or SAE or Ace plumbing rings. Called Benchmark in Sturgis MS. Bought a handful of spares for coffee money. Cheap coffee money. http://www.benchmarkworks.com/

Monte