m9020 xtr brakes pistons not even

[bmar560]

Hi All,

I just bought a new set of m9020 xtr bakes, I had the hoses shorten and installed them last week.
The rear one is fine but I'm having issues with the front pistons, they don't come out evenly, the left one will stick out more than the one on the right.
I've bled them numerous times top down and down up using syringes, but can't seem to get them to come out evenly.

Is this a common issue, google didn't come up with anything, I know there's a known issue with the brakes having floating bite point, but I don't think my issue is the same.

Any other ideas on resolving this ? or does my caliper have to be replaced ?

thanks !!

 

[Flow-Rider]

Try and hold the piston that comes out easy and work the other one in and out a few times. Try not going too far and popping the piston out. It just might be some assembly grease that's making it tight from being in storage.

 

[schred]

Despite being new I'd still suggest pushing the pistons out a little and cleaning with a toothbrush and soapy water in case there was a storage crust on them, then a drop of brake fluid on the piston/seal junction & push them back in. Cycle the offending piston in and out a few times before reinstalling.

Fwiw I've found any differences between the pistons movement is exacerbated by a sh1tty bleed.

 

[teK--]

Might also be an air bubble behind the slow piston. Push the slow one out and in a few times and tap caliper whilst bleeding to get all the air out.

 

[Joe_MTB]

Sounds like a dry seal. Extend the piston and lube with silicone or better still red rubber grease and work the piston. Should free it up, I've had that happen before.

 

[Ky1e]

Sounds like a dry seal. Extend the piston and lube with silicone or better still red rubber grease and work the piston. Should free it up, I've had that happen before.

Yep do this. worked a charm on my new hopes..

 

[bmar560]

thanks I'll try these new things to do tonight
hopefully I'll get this sorted. It's a damn expensive brakes to not work properly

 

[bmar560]

Much better now!
Thanks again
I think there was a trapped air bubble in the calipers

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