R65LS Rear Brake Issue

[Bob_Roller]

My '82 LS had a rear brake problem when I got it .

The adjuster nut was almost bottomed out on the threads of the brake rod before the brake shoes would finally make contact with the drum .

I assumed the brake shoes had been replaced, and standard R65 shoes installed, the LS has a larger diameter rear brake drum, and usually the symptom is you need to adjust the brake until it bottoms out before the brakes even begin to work .

I swapped out the brake shoes from my '84 LS, no help

After messing around for an hour or two, I tried re indexing the arm that comes off of the brake cam to see if it made any difference, I re indexed the arm 5 serrations clockwise and everything is fine now .

I compared the cam to the other R65's that I have, and I found that the dot that is punched into the cam, which is supposed to be in line with the gap in the brake arm, was put in the incorrect spot !!!!!!!!!

It's 5 serrations off, what are the odds ??

If I didn't have another bike to compare this to, I may have never figured this out !!!!!!!!!!!!!

[Rob Valdez 79 R65]

I compared the cam to the other R65's that I have, and I found that the dot that is punched into the cam, which is supposed to be in line with the gap in the brake arm, was put in the incorrect spot !!!!!!!!!

From Duane: See the upper shaft and the two punch marks at about 10 O'clock? I made those punch marks.  This allows one to remove and reassemble it in the same position.



http://w6rec.com/duane/bmw/rear_brake/index.htm


I don't know what punch is "supposed to align with the gap".  It seems Duane made his own punch marks before taking it apart.

[Bob_Roller]

On the '81, 82 and 84  bikes, there are no punch marks on the arm, you line up the punch mark on the cam to the gap in the brake arm .

[Rob Valdez 79 R65]

Duane made BOTH of those punch marks before taking anything apart.

Of course, if a PO took things apart w/o marking them, and put them back wrong, it won't matter.

I'll have to look at my bike when I get home tonight and see if there are any marks on my cam.  (never been apart)

My bike has one punch mark (it looks like a line) and it is lined up with the gap.

[Ed Miller]

On the '81, 82 and 84  bikes, there are no punch marks on the arm, you line up the punch mark on the cam to the gap in the brake arm .

I never noticed any of those marks.  I need to clean my bike more often.

[Bob_Roller]

Ed, I gave up on keeping the bikes looking like just came out of the showroom a long time ago .

Living in a dusty dry environment, they look the same after two weeks, or two months .

With the ongoing construction  at work for the last 11 months, it's a unending battle, and why 'risk' possible corrosion damage to the bike . [smiley=grin.gif]

Now they get washed twice a year, whether they need it or not !!!

[R65Guy]

On the '81, 82 and 84  bikes, there are no punch marks on the arm, you line up the punch mark on the cam to the gap in the brake arm .

I never noticed any of those marks.  I need to clean my bike more often.

You're not blind Ed.  I recently refreshed the rear brakes and o-rings on my 81.  The only marks I found on my arm or shaft were put there by me before I disassembled it.  I was surprised not to find any marks.
Neal