Disc Brakes Rubbing

[Rustybucket]

Help - just fitted new wheels and my front disc brake is rubbing! I've been on Gcn and have followed their videos on removing the pads and pushing back the pistons and also undoing the actual brake from the frame to realignment.

Still rubbing! Anything else to try before I take it into cycle surgery for them to look at?

Thanks for all help!

 

[Flick of the Elbow]

Are they hydraulic or cable ?

My cable BB7 discs rub all the time. Given up trying to adjust them. Every time I just about eliminate it, next time I take the wheel out and back in it starts again. (Just normal quick release, not through axle).

 

[Rustybucket]

Hydraulic with quick release, pretty much brand new bike too

 

[fossyant]

You need to look through the callipers to see where the pads are rubbing - could be a slightly bent rotor which you can fix by pushing or pulling on the warped area. Also look at centralising the rotor between the pads - undo (not remove) the calliper, and gently re-align.

Pretty simple.

 

[Plumster]

Loosen the caliper retaining bolts, apply the brake, whilst applying the brake, tighten the bolts.
Is there any free movement in the brake lever? or does it apply as soon as you touch it? If there is no free movement, you could bleed a small amount of fluid out

 

[lpretro1]

If you have fiddled about with them then they just need to bed in again. Go out and ride....

 

[fossyant]

Psst, just be careful, it's missing a saddle !

 

[Rustybucket]

If you have fiddled about with them then they just need to bed in again. Go out and ride....

Not sure about that, there's quite abit of rubbing and squeaking!

No-rush won't be taking this bike out until at least April at the earliest, don't want it to melt in the rain!

Will have another play around with the discs and rotors tomorrow after my ride!

 

[Custom24]

Are the rotors new as well as the wheels?

You can tell from sighting through the caliper and watching the rotor with respect to the pads as the wheel spins, whether it is a warp or a caliper alignment problem. Use a light If you need it to see the gap.

If warp, the gap will vary as it spins. Use a clean adjustable spanner to tweak the rotor true. You tube it

If alignment, undo bolts and try holding brake on while retightening. Retighten alternately each bolt bit by bit to correct torque. Sometimes, I find holding the brake on gently rather than firmly helps. Also sometimes, better to retighten while monitoring the gap to maintain alignment, rather than the brake on method.

You should be able to see consistent gap each side of rotor all way round. The rotor should not contact pads ideally. Listening for rubbing also useful to identify where you need to true

 

[Rustybucket]

Are the rotors new as well as the wheels?

You can tell from sighting through the caliper and watching the rotor with respect to the pads as the wheel spins, whether it is a warp or a caliper alignment problem. Use a light If you need it to see the gap.

If warp, the gap will vary as it spins. Use a clean adjustable spanner to tweak the rotor true. You tube it

If alignment, undo bolts and try holding brake on while retightening. Retighten alternately each bolt bit by bit to correct torque. Sometimes, I find holding the brake on gently rather than firmly helps. Also sometimes, better to retighten while monitoring the gap to maintain alignment, rather than the brake on method.

You should be able to see consistent gap each side of rotor all way round. The rotor should not contact pads ideally. Listening for rubbing also useful to identify where you need to true

Thanks will try this again tomorrow, didn't really look for the gap Today whilst tightening the callipers up

 

[fossyant]

Thanks will try this again tomorrow, didn't really look for the gap Today whilst tightening the callipers up

That's key !

PS the bike won't fall to bits if you ride it before April !!. You do need to bed the discs in so it doe need some riding.

 

[Rustybucket]

That's key !

PS the bike won't fall to bits if you ride it before April !!. You do need to bed the discs in so it doe need some riding.

Maybe end of March then...

 

[fossyant]

Maybe end of March then...

 

[Rustybucket]

Just occurred to me that I think the brake must have been rubbing from when I bought the bike late last year, but didn't really make much noise. As i remember it definitely seemed hard work to get going on it & my speed was lower than average!

I hope I can fix it tomorrow as I already spent an hour on it today with no success after fitting the new wheels!

 

[mrandmrspoves]

If you have hydraulic brakes - loosen the caliper mounting bolts, squeeze the brake lever hard and while keeping it squeezed tighten the mounting bolts again.
The above method will also work on mechanical brakes which have 2 moving pistons.
On mechanical brakes like BB7's where only one piston moves, adjust the fixed piston to tighten it by about 3 notches. Then loosen the mounting bolts and apply the brake fully. Keeping the brake applied, tighten the mounting bolts again. Then release the brake and loosen off the fixed piston by the 3 notches.
Both above methods will centre your brakes. If you still have rubbing you have either got a warped disc rotor (spin the wheel while looking at the edge of the rotor to see if it is moving laterally) or a seized piston (hydraulic)
seized piston or sticky cable (mechanical)