caliper piston sticking?
#1
03-15-2007, 02:20 PM
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#4
03-15-2007, 06:00 PM
RE: caliper piston sticking?
you still having bleeding issues mang?
you don't necessarily need to rebuild them unless they are leaking cause all you're replacing are the seals anyway...LOTS of them.
to clean it, you need to have brake pressure...unbolt caliper (just one not both) from the forks, remove pads and do the following:
1. extend ONE caliper at a time. wedging a nut or something btwn one set of the 2 opposing pistons so they don't move.
2. ever so lightly pull the brake lever in. you'll see the pistons come out. apply some force to one of the pistons so it doesn't come out, this way the other piston can extend out further.
3. use brake cleaner and wipe off the gunk that has accumulated around the piston. there may be some stuck crap too...so you want to either use sandpaper (like 600 grit) or steel wool to get this stuff all out.
4. gently push the piston in...hold it and do the brake lever again to extend the other pistion and clean, etc. as in step 3.
5. move on to the next set of opposing pistons and do the same.
6. put everything back together, back on the fork and do for the other caliper.
so what is going on with the rest of the brake? if you got all the bubbles out but still have mushy brakes, you may have killed the MC when you were pumping trying to build pressure to bleed the system.
you don't necessarily need to rebuild them unless they are leaking cause all you're replacing are the seals anyway...LOTS of them.
to clean it, you need to have brake pressure...unbolt caliper (just one not both) from the forks, remove pads and do the following:
1. extend ONE caliper at a time. wedging a nut or something btwn one set of the 2 opposing pistons so they don't move.
2. ever so lightly pull the brake lever in. you'll see the pistons come out. apply some force to one of the pistons so it doesn't come out, this way the other piston can extend out further.
3. use brake cleaner and wipe off the gunk that has accumulated around the piston. there may be some stuck crap too...so you want to either use sandpaper (like 600 grit) or steel wool to get this stuff all out.
4. gently push the piston in...hold it and do the brake lever again to extend the other pistion and clean, etc. as in step 3.
5. move on to the next set of opposing pistons and do the same.
6. put everything back together, back on the fork and do for the other caliper.
so what is going on with the rest of the brake? if you got all the bubbles out but still have mushy brakes, you may have killed the MC when you were pumping trying to build pressure to bleed the system.
#5
03-15-2007, 06:21 PM
Senior Member
RE: caliper piston sticking?
I would also recommend using 3 old brake pads against the piston that you don't want to move. Also a space 2 pads thickness should be enough on the ones you're cleaning. I also recommend retracting after cleaning and pushing them back out...sometimes you get a bit more junk. Then apply grease around the piston surface and work it in/out a few times to lube.
#6
03-15-2007, 06:44 PM
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RE: caliper piston sticking?
ORIGINAL: Tahoe SC
you still having bleeding issues mang?
you don't necessarily need to rebuild them unless they are leaking cause all you're replacing are the seals anyway...LOTS of them.
to clean it, you need to have brake pressure...unbolt caliper (just one not both) from the forks, remove pads and do the following:
1. extend ONE caliper at a time. wedging a nut or something btwn one set of the 2 opposing pistons so they don't move.
2. ever so lightly pull the brake lever in. you'll see the pistons come out. apply some force to one of the pistons so it doesn't come out, this way the other piston can extend out further.
3. use brake cleaner and wipe off the gunk that has accumulated around the piston. there may be some stuck crap too...so you want to either use sandpaper (like 600 grit) or steel wool to get this stuff all out.
4. gently push the piston in...hold it and do the brake lever again to extend the other pistion and clean, etc. as in step 3.
5. move on to the next set of opposing pistons and do the same.
6. put everything back together, back on the fork and do for the other caliper.
so what is going on with the rest of the brake? if you got all the bubbles out but still have mushy brakes, you may have killed the MC when you were pumping trying to build pressure to bleed the system.
you still having bleeding issues mang?
you don't necessarily need to rebuild them unless they are leaking cause all you're replacing are the seals anyway...LOTS of them.
to clean it, you need to have brake pressure...unbolt caliper (just one not both) from the forks, remove pads and do the following:
1. extend ONE caliper at a time. wedging a nut or something btwn one set of the 2 opposing pistons so they don't move.
2. ever so lightly pull the brake lever in. you'll see the pistons come out. apply some force to one of the pistons so it doesn't come out, this way the other piston can extend out further.
3. use brake cleaner and wipe off the gunk that has accumulated around the piston. there may be some stuck crap too...so you want to either use sandpaper (like 600 grit) or steel wool to get this stuff all out.
4. gently push the piston in...hold it and do the brake lever again to extend the other pistion and clean, etc. as in step 3.
5. move on to the next set of opposing pistons and do the same.
6. put everything back together, back on the fork and do for the other caliper.
so what is going on with the rest of the brake? if you got all the bubbles out but still have mushy brakes, you may have killed the MC when you were pumping trying to build pressure to bleed the system.
i have no idea why i can't get these to bleed. i just put on a 929 mc (this is the second one i've tried), replaced all the crush washer, and replaced the tube (from the cup to the mc). so i really don't know whats up. the only thing i haven't replaced is the lines (russel) and the calipers.
when i pump them up i can only get the right caliper's pistons to move out, but on the left caliper only one sides' pistons come out. when split them apart i get tiny air bubbles coming up and into the cup. sooooo, i figure there's just air in the lines still. so i get that mity-vac hooked up and when i get to about 15psi a **** load of air comes out. BUT, it doesn't stop coming out and i'll go thru 5+ cups of brake fluid then i get really angry.
i can probably get a pair of tokicko (sp?) calipers, should i try those? could it be the ss lines? how do i know if i "killed" mc?
this is driving me bonkers, thanks for all the help
#7
03-15-2007, 08:32 PM
RE: caliper piston sticking?
oh yea, i forgot about the lube...thanks jaybird...yea lube the sides of the stuff...only one piston comes out cause the others are gumm'd up!
now about the mity vac...you're seeing all these bubbles cause you likely have too much suction and are pulling in air from where mity vac hose connects to the bleeder screw!!! make sure it's really tight there.
only other place would be a hole in your line...and since you can't build any pressure you can't see the leak. bring your ****E over mang...let me work on it already!
nice and slow!
now about the mity vac...you're seeing all these bubbles cause you likely have too much suction and are pulling in air from where mity vac hose connects to the bleeder screw!!! make sure it's really tight there.
only other place would be a hole in your line...and since you can't build any pressure you can't see the leak. bring your ****E over mang...let me work on it already!
nice and slow!
#8
03-16-2007, 03:05 AM
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RE: caliper piston sticking?
ORIGINAL: Tahoe SC
only other place would be a hole in your line...and since you can't build any pressure you can't see the leak. bring your ****E over mang...let me work on it already!
nice and slow!
only other place would be a hole in your line...and since you can't build any pressure you can't see the leak. bring your ****E over mang...let me work on it already!
nice and slow!
but thanks for the help jaybird and tahoe. i'll be hard at work on these things...
#9
03-16-2007, 03:25 PM
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#10
03-16-2007, 04:13 PM
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