# Hydraulic disc brake...whats going on



## enc (Jan 25, 2006)

Im new to hydraulic discs ...

the trailing edge of the pad is sticking. whats going on? can it be fixed?


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## Mac- (Apr 9, 2019)

Are they new pads? Depending on the caliper some need rewinding.


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## slim_boy_fat (Jun 23, 2006)

That looks to be out of alignment, where's the disc?


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## enc (Jan 25, 2006)

Mac- said:


> Are they new pads? Depending on the caliper some need rewinding.


Not sure if they are new. Was on the bike when I bought it.


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## enc (Jan 25, 2006)

slim_boy_fat said:


> That looks to be out of alignment, where's the disc?


Disc is attached to the rim.


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## Caledoniandream (Oct 9, 2009)

Is there damage to the caliper?
While the disc is out don’t press the brake lever, causing the pistons to come out
Try to carefully force the pistons back, remove the “loose” one, and than carefully wriggle the othe one free, check where it catches and check for damage, you can use a fine file and file where it clamps carefully off, little bit at a time.
Make sure the pad is perfectly straight, use no big force but light taps or a little wriggle with a pair of pliers or a screwdriver.


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## ridders66 (May 24, 2019)

That looks like the pads could be warped, the piston can't be bent, otherwise it wouldn't work. Take the pads out, clean everything fully and refit. there may be a small stone behind the pad. I have never seen a set of pads which touch. Something clearly wrong here.


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## enc (Jan 25, 2006)

well , turns out the retaining clip was not fitted properly ...

this is what i found...










after comparing with the rear brake caliper it was obvious the clip was not seated correctly..

this is the rear caliper ...the clip is more central...










and after removing the pin and faffing the clip with needle nose pliers...










fiddly but got there eventually ... buzzing  
saves me a trip to the LBS
Thanks for the sugestions.


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## garage_dweller (Apr 10, 2018)

Is the circlip missing from the retaining pin?


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## enc (Jan 25, 2006)

The rod which goes through the spring clip is threaded and can only be removed by Allan key. 

Having downloaded the xt pad replacement guide from Shimano, it would appear Im missing a clip (snap ring as shimano call it) from the right hand end of the threaded rod (which explains the groove in the rod) I can only assume this is a secondary, fail safe device to stop the rod from falling out in the event the rod somehow unscrews… which is highly unlikely under normal circumstances as it’s bloody tight and removed by Allen key. There’s few if any images online showing the calliper at the correct angle with this clip in place.


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## garage_dweller (Apr 10, 2018)

enc said:


> The rod which goes through the spring clip is threaded and can only be removed by Allan key.
> 
> Having downloaded the xt pad replacement guide from Shimano, it would appear Im missing a clip (snap ring as shimano call it) from the right hand end of the threaded rod (which explains the groove in the rod) I can only assume this is a secondary, fail safe device to stop the rod from falling out in the event the rod somehow unscrews… which is highly unlikely under normal circumstances as it's bloody tight and removed by Allen key. There's few if any images online showing the calliper at the correct angle with this clip in place.


Yes I know how they work . As you say it is a fail safe but bolts in 6 bolt rotors can work loose hence the need for thread lock and with the small size of the allen bolt you can't do it up very tight, not that you would want to as they can seize very easily.

It's not a fail safe I would skip personally.

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## enc (Jan 25, 2006)

im working on some "safety pins"


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