Hi Guys

I recently lost power in the front brake and had to bleed the system.

When I came to test the brake though I noticed that only one piston was moving freely. I’ve had this with other brakes before so lubed and cleaned the other piston but still the same.

I then sent the caliper off to SRAM and it has been returned to me without fault ? again, when I press the brake lever only one piston comes out ?

If I hold the one piston that works, the other piston does come out, but surely they should both work at the same time ? I know this is how my old XT brake worked.

I have been told that the piston on the side with the hose attached comes out and when it meets a restriction i.e the brake disk then the other side will come out ?

Does this sound right ?

Mitch

I have just checked my almost new Elixir R brake which is essentially similar in operation to an XO, and on both front and back, both pistons move immediately the lever is pulled. Not sure if this is true of all elixirs though. However, does your brake work ok in use? when you pull hard on the lever with your finger against the disk/calliper can you feel the disk deflect one way or the other?

I’m just about to refit the caliper to the bike again so will check again, but just pressing the lever with the caliper off only the piston where the cable goes in moves freely. The other does not come out until I resrict the good piston – seems rather odd to me but SRAM and the bike shop recon there was nothing wrong with it ?

mitch

thanks for checking your brake mate

No Problem Mitch.

I can’t find a manual for the X0, but on page 26 of this elixir manual

http://www.sram.com/_media/pdf/avid/dealers/TM_MY09_E.pdf

it gives instructions on how to attempt a fix for a sticky piston which suggests they don’t think that it is normal or desirable.

I also checked on a spare brake ( don’t ask why it is spare) that I have recently rebuilt with a new set of pistons and seals, which does show a hesitancy for one piston to move but almost immediately it will follow the other so they then move equally but with one side very slightly further out- this is easy to fix on the bike by the method they suggest on page 26 outlined above.

Hope this is of use!

edit:

by the way it was the piston opposite to the hose connection that came out first!

Thanks mate – looked at that and have setup the calliper on the bike now – seems better now that it’s come back from SRAM but 1 side does definitely lag behind the other. Will give it a few rides and see what happens

Thanks again

Mitch