Rear Brake dragging

[AApple]

Otay...I know this subject has been discussed before, but a search turns up nothing.
Anywho...I have noticed that my rear brake is dragging big time...to the point of me not being able to turn the wheel with it up on center stand. It will sometimes be ok, then then next time I check it will be almost locked up. Sometimes, it's hard to push the beast out of the garage in the morning to go to work. This has only started in the past few days...maybe a week at the most.
The reservoir is not full, nor empty, but it is a wee tad bit lower than "normal". I did replace the rear pads when I put the new tire on about 3 months ago, as the old ones were almost to the metal. The rotor itself is not in bad shape. I'm wondering now if the rear wasn't dragging some before, and just slap wore the pads out.
I hardly ever use the rear brake, anyway, but I do use it. I would, however, like to be the one to decide whether it is on or not... :head bang: When I got to work this morning, the rear brake was super tight..it took both hands to turn the rim. It sat on center stand all day, and was still almost locked when I got ready to head home. When I got home, I checked it again...and it turned freely... :Awe: (I did NOT use the rear brake at all on the ride home)
Now...I know I've read other posts on this, but I can't seem to find them here. Am I looking at a master issue, or a caliper issue, most likely?
Where should I start, or should I just plan on re-doing the complete rear system...caliper & master?

 

[dan filipi]

The master cylinder return is plugging.

I would try flushing the lines and mc real good with new fluid and see how it goes.
If you still have old rubber lines they could be flaking off. SS lines may be in your future.

 

[toytender01]

:hi: MAKE SURE WHEN YOU INSTALL NEW PADS THAT YOU LUBE REAL GOOD BOTH BREAK HOLDING BINS AND THE SLIDERS...BOB

 

[slabghost]

Yup! What they said. :builder:

 

[joedrum]

old brake line are like one way valves that wont let the brakes relax in a timely manner .....if it sets all day outside and the brakes are locked up its because heat expands the fluid ....locks the brakes in stead of returning to the resivore ....new lines and master cylinder clean up ....oh what a pain in the but i hate brake work but i like to be able to take off and stop on my command :nea: :mrgreen:

 

[AApple]

Tanx, fellers! Looks like a complete brake system overhaul is in the near future... :builder:

 

[AApple]

Ya'll reckon when I put the new pads on, that pushing the piston back in the caliper shoved some doo-doo back up into the master, and created a clog, as Dan suggested? I know I had not had this issue before mounting/installing the new tire, and I put new pads on at the same time. What is weird is, I know I had added a small amount of brake fluid to the reservoir earlier in the summer, because I was needing to pump the rear pedal a couple of times to get any rear brake action. I figure when I installed the new pads, it would overflow the reservoir, but it did not. In fact, it was still low. I see no leaks, either.
So....what's the best line a master cyl rebuild kit?

 

[rkthev]

Joedrum is right. It could be a bad hose. We found this on my brother in-laws motor home awhile back. Right front brake kept dragging. After working on master cylinder and proportioning valve with no help, we found that the hose was collapsing inside and acting like a one way valve. It would let pressure go to the caliper, then collapse and hold the pressure in the caliper. Put a new hose on and it worked fine.
Open the bleeder on the caliper and see if it relieves pressure. If so it is probably the hose or master cylinder. If no pressure, look for caliper binding.

 

[mcgovern61]

What is weird is, I know I had added a small amount of brake fluid to the reservoir earlier in the summer, because I was needing to pump the rear pedal a couple of times to get any rear brake action.

An indication that master cylinder needs a rebuild. Brake fluid might be bypassing the seals (or just low fluid level) causing the need to pump the pedal. Even if the pads are worn, if there is enough fluid, the pedal should apply the brakes the first time without the need to pump. I also agree the hoses need to be replaced.

 

[Smokey66]

I had the same prob with the rear brake draggin.I took the rear caliper and the rear master cyl. apart(MAN THEY WERE FULL OF TRASH) cleaned everthing up and put back together using all the OLD parts and seals(fresh brake fluid of course) and it`s been working great for about a year now.....did I mention I`m kind of a "Low Buck" type of guy...don`t buy new stuff untill you`ve tried to fix the stuff ya got......

 

[Tomahawk]

I would change the rubber lines as suggested and flush the whole system with clean fluid before rebuilding everything. A collapsed hose or or one coming apart could do what your describing. I have had it happen. I expect the master to be okay or it wouldn't hold as well as it does. It would tend to be soft if it was the master. Also a seized caliper would just lock up and not release at all in my experience.

Try a new line from the master to the caliper and flush it out and bleed it real good. If possible use a vacuum bleeder to be sure all the air is out. Wing calipers can be a bear to bleed sometimes. Careful too brake fluid attacks paint and plastic big time

Good luck

Cheers
Tom

 

[AApple]

Thanks for all the tips. I been riding without using the rear brake for the most part...a couple of times I had to, tho, and it stuck pretty good, but then it did loosen up. I know a brake hose can do that...I see it in cars quite a bit. Guess I'll have to start looking for a hose!
I have both a vacuum pump AND a pressure bleeder...bleeding brakes ain't an issue around my place! :ahem:
:thanks: