rear brake staying on

[Little Chick]

Thanx guys for all the replys. I will let u know what happens. Im scared to take it apart but at least i have another one to take parts off of. wish me luck!

 

[boblepp]

Thanx guys for all the replys. I will let u know what happens. Im scared to take it apart but at least i have another one to take parts off of. wish me luck!

You'll need air pressure to push out the piston, make sure you don't aim the piston at a body part or anything which will damage it. Shoot it into a pile of rags in a bucket or something at least. It may come out at high speed even if you can control the air pressure. I've never had to clean up the bore, it has always been corrosion under the seal. It's a very satisfying repair when you get that nice smooth action back!

Good luck!

 

[danf]

Yes yes, try the air pressure first, I read that people actually would get that piston out by using a grease gun to the bleeder fitting, I would think that they are filling the cavity with grease pressure in turn forcing out the piston, air would be my first try, maybe less messy :smilie_happy: , but the amount of pressure from a grease gun would be unmatched. Maybe someone with more experience can confirm any of this as I just read this and not done it..

 

[joedrum]

grease gun is the only ay i do it its safe nd grese only helps in the clea up departmt if its stuck it needs to be cleaned througaly anuway ...un screw the zerk fitting on the end of the greas gun open bleeder ...put the greasegun end on bleeder and tighten it good and snuged up the bleeder and pump ...if you take the pads off you can pump the pistons out while its still on the bike ....orks good for two piston systems when you nededt stopone piston from moving to looden the oher piston ....tenjust take it off the pisto wel come out esy after that ...good luck tough jo just stay with it ou will get it... :mrgreen:

 

[skiri251]

I heard that they use the brake fluid itself. Just remove the caliper off of the rotor and pump the brake pedal.
In my case on other bikes than GL, the air didn't work on some occasion. I didn't use grease gun. I just pulled the piston out with vice grip. I was going to put new piston anyway.

At one occasion I put my finger between the rag and the caliper, and the piston caught it. That was a painful and dangerous experience.

 

[dan filipi]

When I did the rear dual piston popping them out with air pressure, one piston would pop out and left the other in place.
What I did to get them both out was to position the one piston that did pop out back in just barely enough so it would seal the air pressure then used a old pad against the piston and cast housing to hold that piston from popping out. Then applied air pressure to get the other one out.
I've never used grease, only air pressure and I'd only use air pressure because clean up would be a mess and contaminate the brake fluid unless every last bit of grease was removed.

 

[mcgovern61]

I used the brake pedal and just pumped the pistons to near the end and then I turned them gently while pulling and they came right out. When pumping the pedal, one would come out before the other so I just took my large jaw slip lock pliers and would hold one or the other until they were both at the end.

 

[joedrum]

well when im talking stuck ...that means the brake fluid is not doing it and its realy stuck bad...ive never had any problems cleaning things up either ...the greese gun will just out do braking system in a safe way has never failed me or been dangerous

 

[AApple]

I've stayed out of this one until now...mostly because my rear brake was also sticking on, and I was interested in what everyone had to say. I took the time today to fiddle with it some, and got it working again...for free! :yahoo:
The rear brake had been sticking for a while. It started after I replaced the rear tire last summer. It would stick on, but not lock up, and would eventually release. I also noticed the master cyl reservoir was REALLY low(ie: empty!) today, but I had filled it when I did the tire, also. I found no leaks anywhere, but...
Anywho, I took all the crap off so I could get to the caliper. I took the caliper off, and used a small(2") c-clamp to push the piston back into the caliper. Pressed the pedal, and the piston moved out. I did this maybe 10 times, and then got some channel-locks, and twisted the piston around a little. I finally got it to where the piston would move in/out fairly easily, and the piston would retract a smidge on it's own, as it should.
I then took the bleeder out of the caliper, and made sure it was clean, then started pushing the pedal to get fluid to the caliper. Once I had fluid, I hooked up my vacuum bleeder and sucked all the old nasty stuff out, and then bled the thing normally. It's working fine now! I'm sure the rear master is gonna need to be redone, but for now, I'm just gonna ride....with front AND rear brakes, for a change! :yahoo:

 

[Little Chick]

thanx! i will be checkin it out shortly.

 

[toytender01]

I have used the procedure dan described on 2 motorcycles and two trusks all 4 work just fine now :Egyptian: :Egyptian:

 

[54Greybeard]

THAT was a slick fix AApple! Nice going, I'll remember that one.

 

[danf]

thanx! i will be checkin it out shortly.

Little Chick, How's that for answer's to your question, Man alive, I'd say you should be able to get it done or fixed now...Cheers :salute:

 

[boblepp]

THAT was a slick fix AApple! Nice going, I'll remember that one.

I'm sure everyone will agree this is not a "fix" but rather is a workaround, it temporarily frees the piston obstructions, but the locking can and will return any time. Everything you loosened up is still in the fluid and is awaiting to mess up again. I used the clamping trick to be able to move the bike but it quickly returns, especially if stored over winter. Any marks you leave with tools on the outer piston surface may actually become inside the bore when you eventually install new pads so be careful to not mark the metal at all.

But, hey, if you're happy to put off the repair a while this will work. If the pads still have some depth.

 

[AApple]

I did state that the master would prolly need to be rebuilt. :good:
The edge of the piston where I was grabbing sticks out past the sealing surface, and I was very carefully not to damage anything. I also flushed the whole mess...it DID have some nasty old doo-doo in there! It definitely worked well for me today both to and from work(52 miles). Much better that having front brakes only, fer sher! The rear pads are new, also...or they were a few months ago.
Not saying this is the total fix...just that it got mine working again. At least I know now which component was causing the problem. I'll be rebuilding both the caliper and the master this winter, anyway....I hope! :Egyptian:

 

[danf]

Sometimes we all have to get a little creative when we do stuff, we all know that, ok, here it goes, I wasn't gonna tell anyone this trick I dreamed up until I tested it. On the master cylinder there is a Circlip that keeps the piston ect. in place. Well, I cleaned it up well used a small file to make a better groove and the brake pedel would sometimes spring up because that Circlip wouldn't hold...Did this to me a few times, so I came up with a way to keep that sucker from popping out anymore,[groove was too worn] here's where you guys will think I'm crazy, I put the clip on and drilled three small holes at a angle just above the circlip and placed in three small stainless steel screws to hold the circlip in place and contained, It's worked now for over a year with zero issues, I never worry about it not holding anymore..Hopefully you won't ever need to go this far, but it is better than not riding your bike..These master cylinders are getting a lot harder to find too..I know Hillybilly technology...Cost to you three screws..

 

[slabghost]

Or you could do the same with a couple cotter pins.

 

[danf]

Or you could do the same with a couple cotter pins.

Sounds like another opinion to me and a great one at that..cotterpins cool...good one... :Egyptian: It's amazing how we dream this stuff up is it..As long as that Circlip is trapped is all I care about..Never to pop loose again..

 

[slabghost]

In the Army we safety wired everything on helicopters. Same basic principle with cotter pins. Just block the ring from coming out.

 

[Little Chick]

replaced caliper still stickin a bit. master cylinder is next. thanx for all the input guys!