Major brake pad rub - (hydraulic disc, maybe pistons?)

king_jeffers
king_jeffers Posts: 694
edited June 2011 in MTB workshop & tech
Hi Guys,

I changed the brake pads front and back a couple of days ago. The front is fine but the rear is driving me nuts.

Towards the end of my commute home today I noticed when I apply the rear brake the bike begins to judder, I could also hear a rubbing noise coming from the back, this is when cycling normally.

I got home, took the rear wheel off and removed the pads. I notice one of the pistons is sticking out quite a bit further than the other one. When I apply the brakes it exacerbates this.

So I gently try to ease the pistons back into place, pop the pads in and they close up. I open them up manually (screwdriver), put the wheel back on and it no longer turns freely.

Bike is fitted with Tektro Auriga Pro, hydraulic disc, dual piston with 160mm rotor. I've checked the documentation on the website and scouted a few posts and can't seem to find out how to fix it, any ideas?

I understand the caliper might need to be aligned but I have no idea how this is done. Help

Edit! Found a couple of videos on youtube re caliper adjustment, carried this out and it made no difference, the pads seem to really tight together.

Also pistons extend, well one does, and id doesn't retract.

Any ideas?

Comments

  • nicklouse
    nicklouse Posts: 50,675
    too much fluid in the system. allow some out from the lever end.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • king_jeffers
    king_jeffers Posts: 694
    nicklouse wrote:
    too much fluid in the system. allow some out from the lever end.

    So ignore the bleed nipple on the calliper just slacken off the screw on the leaver and let a small amount out then try reset the pistons if needed?
  • king_jeffers
    king_jeffers Posts: 694
    Sooo.... let some fluid out. Only a very, very small amount and now the damn brakes won't do a thing and the piston is still sticking out. Wend to halfords for a bleed kit, have to order them in and could take a while... Came home and ordered via chain reaction cycles instead... hopefully quicker. No commute for me tomorrow :-(
  • nicklouse
    nicklouse Posts: 50,675
    why do they need bleeding?

    did you pour all the fluid out?

    have you now reset the pistons by pulling the lever a few times to pump them back out?
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • king_jeffers
    king_jeffers Posts: 694
    nicklouse wrote:
    why do they need bleeding?

    did you pour all the fluid out?

    have you now reset the pistons by pulling the lever a few times to pump them back out?

    Pumped the level a few times, one of the pistons comes out (fails to noticeably retract), the other side does not move at all... very odd!
  • mattrixdesign2
    mattrixdesign2 Posts: 644
    My Spesh has Tektro Auriga Pro - and I have a bit of sticking piston.

    It has never been completely resolved, but after replacing the pads, and loosening the calipers, apply the brakes, tightening the calipers I seem to have improved things, but the piston still seems to stick/lack movement of the others.

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