Avid BB5 pads wonky

TomvanHalen
TomvanHalen Posts: 181
edited February 2013 in Workshop
Okay, this is driving me up the wall. Is there any way to get the fixed pad on Avid BB5 brakes to sit straight and flush? No matter how much I fiddle with it, the bottom of the pad sticks out towards the caliper feeling all springy and doesn't straighten up until you brake with it, so it's impossible to get a good lever feel without brake rub.

My rotors are no less true than any I've had on an mtb before, maybe a 1/4 mm, but I can almost pull the levers to the bars, even with the faintest rub on the most out of true part.

Comments

  • Monty Dog
    Monty Dog Posts: 20,614
    Remove the pads and check to see if there's anything between the caliper and pad to make it sit not straight - perhaps the pad isn't seated correctly - particularly the locating pip. Frankly, they're not complicated so should be easy to sort.
    Make mine an Italian, with Campagnolo on the side..
  • Had a good look last night, the pads are definitely seating properly, but the piston for the fixed pad seems to be able to rock about a central pivot, so when the pad spreader is put in, it presses the top of the pad away from the rotor. Fscking stupid thing.

    No one else have this problem? Might see if I can take it apart and put a shim in to stop the movement and keep the piston straight
  • logie48
    logie48 Posts: 30
    Anything like this?

    643884_368157489936349_316275528_n.jpg
  • Pretty much exactly like that, yes. I think I've found a way to reduce it and am trying it out on the front caliper; if there are no problems I'll do it on the second and post some pictures. If anyone else has had any luck though...
  • Mine does exactly the same thing. Removing the spreader clip seems to help, seems like a design fault. Unless anyone has managed to correct it?
  • My fix seems to have helped and I'm not dead yet, so I'll do the rear soon and post a pictorial
  • Okay, while the front worked, I've managed to knacker the rear caliper trying to reattach the moving piston (tightening the fixed pad to press it back on with an additional shim the fixed piston has seized in place) so I can't exactly recommend it.

    So, if you can get the whole moving piston out (I couldn't), it's probably safe to try it. This is what I was going by:
    http://forums.mtbr.com/brake-time/avid- ... 57262.html