Rear brake question

[flongr65]

Took my bike out today from winter storage. The rear brake barely works. Was fine when I laid it up in Dec. R65 has 23,000 original miles, Any thoughts on what might be the problem?
Thanks, Frank

[drewboid]

A little more informatiion needed -
what do you mean barely works?
What year - disk or drum brake?
the pedal doesn't move?
The pedal moves but the shoes don't?
the shoes move but the bike doesn't slow down?
The pedal has to move too far to start braking?
Is only one shoe moving?

You will have to pull the rear wheel to fully check this out.
Are the brake shoes contaminated with water, oil or grease? If the drain hole in the bottom of the final drive is clogged rain water, oil, etc will fill  the space below the splines and drip onto the brake drum.

If the cams are corroded in the sleeves the shoes won't move properly.

Brake show linings do harden with age and stop working - how old are yours?

I do find that the rear brakes are not really as effective as I would like; however you should be able to lock up and skid the rear wheel with a lot of pressure on the pedal. (at low speed please - we don't want to do a high side flip!)  

You may be able to improve braking by breaking the glaze on the shoe and drum with emery cloth (temporary fix).

To adjust the rear brake I get the rear wheel off the ground and slowly tighten the winged thumb nut on hte adjusting rod while turning the wheel by hand. the nut has high and low places. At the first sign of drag at the high point I back off a 1/4 turn.  YMMV - this works for me.

[montmil]

...You may be able to improve braking by breaking the glaze on the shoe and drum with emery cloth (temporary fix).

This does help some as I've tried it on the '81.

New R65 shoes are available, without a core swap, from:

http://www.denniskirk.com
http://www.motobins.co.uk/

Monte

[Semper Gumby]

HI FlongR65,

What year is your bike?  Is there rear diff oil leaking from the seal?  Maybe some grease got on the pads from the wheel spline?

Good luck,

[flongr65]

Bike is 1981, with drum rear break, 23,000 miles. When you step down on the rear brake peddle it slowly grabs but not enough to stop the bike. When the bike is on the stand and you spin the rear wheel and push down on the peddle it stops, but under speed it barely stops the bike. Front disc works fine. New master cylinder and front pads but drum break is original. As I said when I laid it up it worked perfectly.

[flongr65]

Thanks guys, problem solved !! Scuffed up the drum pads and adjusted the peddle rod as suggested

Frank

[Yikes]

Over the last 3 months, I  lost pretty much all braking power on the rear of my '83.  I pulled the wheel and found things very wet with oil.  A good cleaning of the drum interior and sandpapering of the inner drum face and the surface of the shoe got me back up to an acceptable level of braking power.  I'm not sure if the source of the oil is leaky O-rings on the cam or the rear seal.  (Darkness was falling when I did the work so it was hard to see what was happening in there.)  I'm thinking I will replace the O-rings first and see if that dries things out in there and If not, then do the seal as well.  Not sure how involved that job is yet.  Once that is done, I'll spring for some new non-oil-soaked shoes.  It is good just to have a rear brake again!  

Now after four days of solid rain here, I'm looking forward to doing some riding again! [smiley=clap.gif]

John M

[drewboid]

John,
check the drain hole below the splines in the final drive. It should take care of any minor leakage and any rain water that penetrates.

I had over-greased the splines and the excess grease blocked the drain. the next time it rained the water had no place to go so it mixed with the grease and contaminated the brake shoes! Now I make sure the drain hole is open. I don't think the hole is straight so you need a flexible wire or pipe cleaner to make sure it is open.