Rear brake starts sticking after rides

[Twanginblues]

I've used the search feature and couldn't find any relative posts so I thought I'd ask in a new one.

It seems like everything is fine before I ride. Granted there is a tiny bit of drag on the rear brake but, I'm hearing that is normal. After I ride it to work (20miles) it seems like the rear brake is half way pressed down. When I park the bike in the driveway, walk in the front door, open the garage and push the bike in....it drags a lot! To the point where it's rather hard to push it.

Any ideas what this could be?

Thanks!

[BA80]

Can you reach down and pull the pedal up and release the rear brake when that happens?

[crazy steve]

.. Granted there is a tiny bit of drag on the rear brake but, I'm hearing that is normal...

You've got more than a 'tiny bit' probably. After a ride, how hot is the brake rotor? Too hot to touch? If it is, the chances are good that your brake piston/pads aren't retracting enough and a rear brake rebuild in in your future. Could be either the caliper or the rear master cylinder, I'd disassemble/clean both. To narrow it down, after your next ride and if the brake is dragging, try 'cracking' the bleed screw on the rear caliper; if the brake now releases, it's the master cylinder.

[BA80]

What I was getting at Steve was the shaft that runs through the frame for the rear brake pedal may be rusted and sticking, holding the rear master cyl from releasing fully.

[crazy steve]

Granted, a rusty pedal shaft could be a contributing factor, but he says that 'everything is fine' before riding so I doubt that the pedal is releasing itself when the bike is sitting. More likely is a hot brake from dragging, which will give a low pedal...

[Tat2demon]

I had the same thing happen. I pulled the rear MC and it was packed with gunk.

[ViperRon]

Same symptoms I had when my rear master went bad. I put it off and put it off just working the brakes draining and refilling with fluid. It did not work. It left me stranded on a lonely road on a hot day working on it with no shade.

Don't get stuck on a lonely road on a 100 degree day with no shade. Take it all apart clean it all and rebuild all that needs it. IF IN DOUBPT GET REBUILD KITS.

[DGXSER]

Don't get stuck in a roadside ditch!!

Don't get stuck in a roadside ditch.

Sorry Ron, just had to play on your terminology there....

I agree with the thought to clean up the rear brake system if you have not done so yet.

[ManagerMike]

You need to determine the base cause for the brake dragging in the first place (adjustment, MC, caliper piston or caliper slide binding, or collapsed brake hose).
I don't care who said what, any brake dragging on any vehicle of any type can never be shrugged off as "normal".

The reason it gets worse after a 20 mile ride to work is the heat from the dragging causes the brake fluid to expand, causing more drag, causing more heat, causing more expansion, causing more drag....... eventually, the brake will drag to the point the the bike is unridable, or, if you continue to push it, the brake fluid will boil rendering the brake utterly useless, which I hope noboby will ever tell you is "normal".

The first and simplest check is the adjusment, do you have enough free travel in the brake pedal? Despite a locknut, vibration does happen.
If I sound a bit too earnest forgive me, but we are talking about brakes after all.

[DGXSER]

The reason it gets worse after a 20 mile ride to work is the heat from the dragging causes the brake fluid to expand, causing more drag, causing more heat, causing more expansion, causing more drag....... eventually, the brake will drag to the point the the bike is unridable, or, if you continue to push it, the brake fluid will boil rendering the brake utterly useless, which I hope noboby will ever tell you is "normal".

I can attest to this from experience on an XS750. Got the bike for basically free. The bleed screws on the front calipers were broken off. I never did the work to fix them, just rode the bike. As I would ride it the front brakes would lsowly get tighter and tighter until when you let off the throttle the bike would stop!! I dropped it more than once from that, this was back in my much younger dumber days. Well, eventually, the fluid did give out, and was coming down a hill with no brakes, up to a redlight at a three way intersection. I honked the horn and luckily people stopped as I ran through the light to the right side of my lanes across the corss street. bike hit the curb, jumped about three feet in the air, came down on the side walk and I rode it to a stop using the rear brake.

Do not let this be you.....it is NO FUN!!!