break problems

woodrrow

Registered
brake problems

Ok so my rear caliper isn't wanting to open up at all.. I had to take it off and pry it open with a screw driver. The pads are gone now. Brake fluid is good. What could the problem be? I've never messed with brakes before on any vehicle..
 
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Calipers are a pain to open up there is actually a tool for car calipers that makes it easy most people use a piece of wood and a C-clamp are you replacing the rear brake?
 
I just plan on changing the pads. Whenever you release the brake aren't the pads supposed to release the rotor a bit? I took the caliper off, turned on bike and pumped the rear brake and the brakes just closed up all the way. When I release it the pistons would open up 50% of what they just closed. So every time I pressed the brake pedal they came closer and closer together.
 
one of my friends just had this happen to her, the pads would compress but wouldn't let them back out and it ended up that her master cylinder had trash in it and she had it replaced and that solved the problem.
 
I just plan on changing the pads. Whenever you release the brake aren't the pads supposed to release the rotor a bit? I took the caliper off, turned on bike and pumped the rear brake and the brakes just closed up all the way. When I release it the pistons would open up 50% of what they just closed. So every time I pressed the brake pedal they came closer and closer together.

Im no mechanic, but I am pretty sure they arent supposed to open all the way up to what they were before pushing on the brake. I believe when you let off the brake, the spinning rotor actually kinda pushes them a little bit, just barely. The pads are just barely hovering over the rotor. This is also why you shouldnt press on the brake when the wheel is off, or it can be a pain getting them open again haha...

But then again, I am no mechanic.
 
Whenever you release the brake aren't the pads supposed to release the rotor a bit?
Yes, but just enough to where the rotor spins.

I took the caliper off, turned on bike and pumped the rear brake and the brakes just closed up all the way.
There's no need to turn the bike on, the brakes are not power assisted.
Yep, they're supposed to close up (on the rotor) when the brake is applied.

When I release it the pistons would open up 50% of what they just closed.
??? Not supposed to do that.

So every time I pressed the brake pedal they came closer and closer together.
Exactly, that's what they're supposed to do, but with the rotor between them. It's when you release the brake lever and the calipers don't release at all and the pads maintain constant braking pressure on the rotor that you have problems.

Since there is no spring to pull the pads away from the disc, the pads always stay in light contact with the rotor (the rubber piston seal and any wobble in the rotor may actually pull the pads a small distance away from the rotor). This is important because the pistons in the brakes are much larger in diameter than the ones in the master cylinder. If the brake pistons retracted into their cylinders, you'd have to pump the brake lever several times (each time you wanted to stop) just to pump enough fluid into the brake cylinder to engage the brake pads.
 
Ok, I've never worked on my own car because I have a mechanic friend who I always trade work with. But I want to wrench on my bike though, so thanks for all the input fellas. Sounds like all is good I just need new pads :whistle:
 
Yes, as the book says, NEVER squeeze the hand brake or push down on the foot brake
when you have the rotor out.!! I changed my pads recently and found an easy way to push your
pads or pistons back. You'll need a couple of those wedge shaped wooden door shims. You push
a shim in from each side of the pads and as you push them in, they push the pistons back
into their cylinders. I hope I've explained that right. It works really good and there's no chance
of damaging anything because it's soft wood.
 
Probably too much brake fluid in the pump.Check the level of it when the pads refuse to move inwards further more.??? Pads never return back when you release the lever ..not even a bit , unless something forces them to do so...eg rotor.Another reason ,besides liquid,can be the sealers o.If your bike is older than 7 years they maybe need replacement ,Also try first to clean the pistons when they are at their outer possible position.Its really difficult to force a dirty piston to moove through a tight sealer.
 
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Take the top off the master reservoir and take out about half of the fluid. It should be easier to push back the pistons with the top off the reservoir. You should probably clean the pots before you try pushing them back in. Use some brake cleaner or WD40 and wash it off after. Then push in the pots.
 
Take the top off the master reservoir and take out about half of the fluid. It should be easier to push back the pistons with the top off the reservoir. You should probably clean the pots before you try pushing them back in. Use some brake cleaner or WD40 and wash it off after. Then push in the pots.
I usally use brake cleaner spray and a toothbrush before EVERY pad change.
 
Hey Woodrrow, your always more then welcome to come over and have Randy help ya out...:laugh: Don't tell him I said that.:whistle:
 
Haha, aight thanks. Yea I talked to him yesterday about it. If everything is functioning properly, which now it seems to be, I shouldn't have any problem putting new pads on.. I'll find out tonight though.
 
Many DIY folks swap out the pads, but neglect to clean the caliper pistons. This can lead to uneven pad wear (due to pistons sticking), pads dragging or brake failure.
Below are 2 videos from Dave Moss, these and many others can be viewed at Catalyst Reaction. Lots of good info on suspension tuning!
 
I was planning on cleaning it all with a toothbrush & brake cleaner. Thanks for the link though rusher, very helpful.:thumbsup:
 
If you haven't figured out your problem yet, check your brake line. Pull it off and try and blow through it from the caliper side to the resevoir side. The inside of the brake line could have colapsed on you which will cause the brakes to apply, but not let the pressure back to release. I had this happen on my moms truck, she could apply the brakes and stop, but the driver front wouldn't release. The inside of the rubber line had collapsed. Changed line, bleed the air out and she was good to go. Just something to try.
 
If you haven't figured out your problem yet, check your brake line. Pull it off and try and blow through it from the caliper side to the resevoir side. The inside of the brake line could have colapsed on you which will cause the brakes to apply, but not let the pressure back to release. I had this happen on my moms truck, she could apply the brakes and stop, but the driver front wouldn't release. The inside of the rubber line had collapsed. Changed line, bleed the air out and she was good to go. Just something to try.
Hey......!!! We both live to the same city Athens by name only.You're in Ga ....I'm in Greece.Your point is good , but very rare to happen on a bike JMO :beerchug:
 
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