How to adjust disc calipers?

jimmy5willy

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So I just bought my first ever set of hydraulic disc brakes.
I put new pads in and they are almost touching. No way the disc is gonna fit between.
Is there any adjustment/way I can back the pistons off a bit?
They are modern Shimano XT brakes. Help!
 

dyna-ti

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Pistons are sticking out.

Take out the pads and using the back of a spoon handle prise them apart.

#IMPORTANT. Try to keep the piston square as you push it in. You might be able to do this with your thumbs, using both openings, which is also a way to judge how easily the pistons are moving in their sockets.

You should never pull on the lever beyond 1/2" just to see if they move. Any more than that and they come out further as there is no fixed rotor in between.
 

Supratada

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Take pads out, put in suitable tool to spread pistons back out, ie push them back in the body. Should be easy if they are not seized. If they won’t budge, you might have to remove reservoir lid or plug/screw to allow some fluid to seep out.
 

dyna-ti

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Actually if those are 2nds then do as follows

Remove pads
Pump lever till pistons come out 10mm or so, but no more, and you might find one comes out further. If so using your thumbs push it back a bit, or hold it til the other piston comes out about equal
DO NOT PUMP OUT TOO FAR, or the piston will fall out completely.
Use cotton bud to clean pistons using Isopropyl Alcohol.
Use cotton bud to lube with silicon lube
Push piston back in.
Repeat a couple of times till both are cleanish and move easily when you jiggle the lever a little bit.

With the piston pushed back in fit the pads and attached to the frame and shim or adjust till it is spot on exactly centered and dont skip here, take whatever time is needed, frustrating as it is on PM, stick with it :cool:
 

jimmy5willy

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Re:

So theres no adjusters as such, it's just push the pistons back physically?! Random. I thought there might be a winder or something somewhere.
Ok I'll give this a go. Cheers.
 

jimmy5willy

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Re:

You guys nailed it.
Took the pads out again, sprayed the pistons with brake cleaner and pushed them back with my fingers.

Brakes are sharp as sh!t now!
Thanks for all the help.
 

Supratada

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Sharp as a tack, surely? Sh’#£ is soft, hence the saying, soft as sh’#3.
Although you can freeze it and use it as an impromptu cosh / cudgel.
 

captaincowelly

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Just stumbled across this,very late to the party but looks like you're missing the steel spring that sits between the pads,it pushes them back against the piston as it retracts.
Not a show stopper,but if the pads are moving in and out fully,they're less likely to start sticking.As it is they may just stay close to the disc and the pistons will be moving to meet them instead of pushing them all the way.
If that makes sense?
 
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