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sticky piston on my...
 

[Closed] sticky piston on my shimano's..advice needed please

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[#613381]

they're fairly new so not covered in shitee,

so with pads out i pumped the pistons out, cleaned (not very much) gunk off the pistons with some IPA relubed them with some brake fluid and popped them back in, they went back in with little resistance so all good me thinks.
when centering the caliper on the bike one piston is still coming across more than the other and hence dragging on the disc, apart from repeating the process is there anything else i can do..?


 
Posted : 07/06/2009 10:11 pm
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You could try using red rubber grease - its a better lube than brake fluid

Work the pistons in and out a few times/


 
Posted : 07/06/2009 10:29 pm
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You can hold the piston that comes out too much back with a screwdriver, and [u]gently[/u] work the lever, the other one can move, and you can balance them out a bit.


 
Posted : 07/06/2009 10:31 pm
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yea may try that, is that the stuff for car brake pistons thats hard to find anywhere to buy..?
nickc, yea cheers i did try that to no avail.


 
Posted : 07/06/2009 10:33 pm
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you can get red rubber grease on ebay..

i got some last week in a little pot 🙂


 
Posted : 07/06/2009 10:36 pm
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Check the quality of the anodising on the pistons. My XTs had discoloured anodising for the first few mm and it caused them to be sticky when new pads were used. But I'd run them for 4 years. They were fine a bit further into their "travel".


 
Posted : 07/06/2009 10:36 pm
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Try a motorcycle shop for small quantities of the red grease.


 
Posted : 07/06/2009 10:37 pm
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cheers all,

the anodising is just fine an dandy.
will pester my local motorbike shop tomorrow


 
Posted : 07/06/2009 10:40 pm
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Did you use "brake fluid" in the traditional (DOT 4) sense, or "brake fluid" in the Shimano (mineral oil) sense?!


 
Posted : 08/06/2009 6:53 am
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This happened before on my XT brakes (started doing it after about six months) - as mentioned before give the pistons a good working back and forth and wipe around them with a cotton bud dipped in Shimano brake fluid. Repeat for 10 - 20 times(?). As Nick says hold the good piston while you work the sticky one free if needed - and just be careful to wipe as much brake fluid away as you can otherwise you'll contaminate the pads like I did 😕


 
Posted : 08/06/2009 7:07 am
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jimbo as in mineral oil, wont go near them with dot fluid..!!

pbr- i'll just keep doing it until its free, i only cleaned and worked piston 3/4 times so maybe i was being hopeful...

red rubber grease ordered.


 
Posted : 08/06/2009 7:40 am
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update.

red rubber grease arrived this morning from evilbay (100ml for £2.85)

cleaned off again and applied said grease, worked piston in and out 3-4 times and hey presto all is good in the world again.

cheers all for your help


 
Posted : 09/06/2009 2:09 pm
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This thread has been really helpful, I've been having the same problem with my rear SLX.

Off home to fix it now.

It's great when STW works like this!


 
Posted : 09/06/2009 4:58 pm
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aye, tis the font of all knowledge when you need something bikey

oh and its a font of rather a lot of shite when talking about most other things!!! 😆


 
Posted : 09/06/2009 5:27 pm