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DT125R Forum -> CALIPERS -> Rear Caliper/Piston Problem!?
Post Info TOPIC: Rear Caliper/Piston Problem!?
NEV


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Rear Caliper/Piston Problem!?
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If that were me, I'd connect the pipes back up again so as to try and get pressure behind the piston, no need to connect the bracket up mind, then spray penetrating oil around the piston give it a while to soak, and break the crap thats making it stick, failing that try some freeze spray into /onto the piston, hopefully it will make it contract enough to free itself with a pump on the pedal, but remember if it does work, you'll need to thoroughly, clean the caliper afterwards, deffinately replacing seals, and possibly the piston too.

You could also whip off the caliper, and nip down to your local garage workshop that has a compressed airline, and see if they can 'pop' it out for you, they'll only probably ask for a couple of quid to chuck into their tea money.



-- Edited by NEV on Tuesday 24th of January 2012 12:10:12 PM

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Mattydav


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Ok well heres my problem

 

i went to change my rear pads and when attempting to push the piston back i realised it was seized up. i checked online and seen that if you push the piston out and replace the seals and piston then it should be okay, one problem is i cannot get the piston to move even when i press the brake pedal down.

 

I've removed the caliper, made sure that fluid is coming out of the flexi and it drips out fine, i put the caliper back on, bled the rear brake by pumping the pedal, holding it down, openining the bleed nipple. i repeated this until there was fluid squirting out when the pedal was compressed and tightened the nipple up.

 

When i then pumped the peddle, still the piston didn't move at all. i tried fitting another 2nd hand caliper which i had spare, repeated the process and the piston didn't move.

 

Maybe its something im doing incorrect but i need to get my bike on the road ASAP, so if anybody has any tips on what i should do please fire away, would be much appreciated thank you! 



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MJDavenport
Mattydav


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Okay well i put the caliper back on, bled the system, pumped the peddle, i can see the piston moving up and down but in the very slightest, not enough to push the piston out.

I've sprayed oil down the side of it and let it soak in but its not budging. could it be anything else like the master cylinder or flexi? i dont see how if the fluid is coming out of the caliper bleed nipple when the peddle is compressed but its like there isnt enough pressure to pump the piston out.

How would a garage pop out the piston with the airline, how would that even work?

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MJDavenport
NEV


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"How would a garage pop out the piston with the airline, how would that even work?"
Trust me it does, just dont be standing in front of it when it does,
As for why the piston moves slightly, maybe the seal has twisted itself out of its seating and has raised its profile against the piston, therefore jamming itself up against the piston.

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NEV


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How much did you open up the nipple?

I use this method, over a few years I've done many ways but found this simple way the easiest and cheaper than forking out for a bleed pump machine. Cost about 70p and saves ages, plus you can do it by yourself.

 

 

Uploaded with ImageShack.us

 

 



 



 



-- Edited by NEV on Thursday 26th of January 2012 05:22:04 PM

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Mattydav


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Ok i bought a new caliper off ebay, i fitted the caliper, bled the brakes by pumping and holding down the peddle then opening the bleed nipple.

I cannot seem to get any peddle, its soft and not alot of pressurisation ?

I need some help as i need to get the bike back on the road asap for work ect...

What would you reccommend ?

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MJDavenport
Mattydav


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i didn't really open it a specific amount, i just opened it until the fluid came out, why is there a specific way to do it?

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MJDavenport
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Less is more, so to speak

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