Disc brake caliper not centering.

[Hulk_slogan]

Hey all. Not sure how it happened but my rear disc brake is rubbing. Its the inside pad that is rubbing constantly on the rotor.

Its a pain getting the bike in and out of the car so Something could have been knocked I suppose.

I tried loosing the caliper and squeezing the brake lever and retightening the caliper bolts while the brake lever is held, but as I'm tightening the top caliper bolt, it moves the caliper no matter how firmly I hold the brake lever.

Can the caliper be tightened etc and centered without pulling on the brake lever? Seems like it doesnt move around as much when tightening the bolts that way.

 

[cyberknight]

What bike/brakes do you have ?
The tektro brakes on my subway were a pain to get right as only the outer pad moves with the brake lever / barrel adjuster and the inner pad is adjusted by an allen key on the inside of the brake caliper .
Once i had it right they have stayed right.

 

[raleighnut]

If its a hydraulic system you may have a sticky cylinder, cheaper cable op types (as on my Saracen) have an adjuster that slides the caliper across and an Allen key to take out slack on the 'static' pad.

 

[Hulk_slogan]

Ah sorry for the lack of details. Yeah they are mechanical disc brakes, hayes mx to be precise. Bike is a b'twin rockrider 500.

Everytime I attempted to 'centre' the caliper by holding down the brake lever and tightening the bolts, the caliper moves as a result of tightening the bolt, no matter how careful or gentle I go!

It results in the static pad pressing right up against the rotor. I can adjust the static pad, but I havn't yet as the brakes were fine one day and not the next!

There is also a little allen head grub screw on the static pad side of the caliper, any ideas what this does?

 

[User33236]

With cable disc brakes I found it easier to loosen the caliper retaing screws, wind the pads in clamp the rotor, retighten the caliper retaining screws and back the pads back out by the appropriate amount.

This give me less movement, when retightening, than trying to hold the brake on and allows me to fine tune the rotor centring by how much each pad was wound in.