M
Michael Slater
Guest
So the pistons got pumped out on both the front and rear brake of my wife's Trek Liquid 20. This
bike has Hayes Hydraulic disc brakes. When the pistons get 'pumped out,' there is continual friction
between pad and disc.
Reading through the service manual and the online manual
(http://www.hayesdiscbrake.com/pdf/General-45-14575A.pdf), the short answer is to remove the pads
and then 'walk the pistons back into their bore.'
Well, much easier said than done. The pads come out easily, but getting the pistons back in the bore
seems to be impossible. I can get them in, and the rubbing between pad and disc is much reduced, but
it's still there. The rear brake is more difficult than the front.
The instructions suggest using 'the box end of a 10mm end wrench.' I used exactly that instrument,
and it was not clear to me at all how this is the magic implement for doing this. I still am left
with either a tiny lip of the piston still overhanging the bore, or else one side shoved in
adequately and the other side poking out terribly. Either way, there is still friction.
Before I drag this thing back to the shop to get it corrected 100%, does anyone have any suggestions
about how to do this exercise more effectively?
It's a really alarming problem, because it's not that unlikely that the brake lever will be thrown
while the wheels are out (like in the back of my car, for example), and I didn't notice any
lock-outs on the brake pads or levers to prevent it.
regards
[email protected]
http://karavshin.org
bike has Hayes Hydraulic disc brakes. When the pistons get 'pumped out,' there is continual friction
between pad and disc.
Reading through the service manual and the online manual
(http://www.hayesdiscbrake.com/pdf/General-45-14575A.pdf), the short answer is to remove the pads
and then 'walk the pistons back into their bore.'
Well, much easier said than done. The pads come out easily, but getting the pistons back in the bore
seems to be impossible. I can get them in, and the rubbing between pad and disc is much reduced, but
it's still there. The rear brake is more difficult than the front.
The instructions suggest using 'the box end of a 10mm end wrench.' I used exactly that instrument,
and it was not clear to me at all how this is the magic implement for doing this. I still am left
with either a tiny lip of the piston still overhanging the bore, or else one side shoved in
adequately and the other side poking out terribly. Either way, there is still friction.
Before I drag this thing back to the shop to get it corrected 100%, does anyone have any suggestions
about how to do this exercise more effectively?
It's a really alarming problem, because it's not that unlikely that the brake lever will be thrown
while the wheels are out (like in the back of my car, for example), and I didn't notice any
lock-outs on the brake pads or levers to prevent it.
regards
[email protected]
http://karavshin.org