Hydraulic discs rubbing, is that ok?

MrVoila · 08-29-2010, 05:00 PM

Hi everyone. New to the forums, and am excited to learn a lot about maintenance from you all! When I transport my bike in my car, I have to take off the front wheel and put a spacer in between the pads. Recently, I forgot to put the spacer in and accidentally pulled the brake ever so slightly. Now the inside brake pad (i.e. the one closest to the frame) is rubbing just a bit when I spin the front wheel, but the outside pad is fine. I can see light through the inside gap just a bit, so it looks as if wear on the pad will alleviate the problem. I took my bike in to a shop, and they told me to 'ride the hell out of it' and the pad will wear down.

My question is this: is that a good idea? Will riding with the slight rub of the pad hurt my brake system or rotors? Thanks for your help everyone!

dave_sd · 08-29-2010, 07:52 PM

It will generate unnecessary heat, but wont really hurt anything. I have to recenter my disc brakes all the time because of various reasons. Typical method is to take off your wheel and loosen the bolts holding the caliper to the adapter bracket on your fork, and spread the brake pads with a spreader. A flat head screw driver can work if you're careful, but you can gouge your pads pretty easily. If you do, you can take them out and smooth them on a piece of sand paper lying on a flat surface. The spacer you have will probably do the trick better than a screwdriver. Anyway, you're basically pushing the brake drums back into the caliper to get more space between the pads. Once they're spread, but the wheel back on, and then squeeze the brake lever hard 5 or 6 times. Then squeeze the snot out of it and snug up the caliper bolts again. When you let go of the lever the disc should be centered between the pads again. Spin the wheel to be sure (redo the bolt snugging process and the hard brake pull if it's not), and then you can tighten up the bolts to their recommended torque value (usually 7 N-m, if memory serves). I've found that just taking off the wheel and putting it back into the dropouts can screw up the disc alignment, though. You can sometimes correct the problem buy pulling on the quick release lever, wiggling the wheel, and tightening it back up.

Good luck!

-Dave

MrVoila · 08-30-2010, 01:36 AM

(08-29-2010, 07:52 PM)dave_sd Wrote: It will generate unnecessary heat, but wont really hurt anything. I have to recenter my disc brakes all the time because of various reasons. Typical method is to take off your wheel and loosen the bolts holding the caliper to the adapter bracket on your fork, and spread the brake pads with a spreader. A flat head screw driver can work if you're careful, but you can gouge your pads pretty easily. If you do, you can take them out and smooth them on a piece of sand paper lying on a flat surface. The spacer you have will probably do the trick better than a screwdriver. Anyway, you're basically pushing the brake drums back into the caliper to get more space between the pads. Once they're spread, but the wheel back on, and then squeeze the brake lever hard 5 or 6 times. Then squeeze the snot out of it and snug up the caliper bolts again. When you let go of the lever the disc should be centered between the pads again. Spin the wheel to be sure (redo the bolt snugging process and the hard brake pull if it's not), and then you can tighten up the bolts to their recommended torque value (usually 7 N-m, if memory serves). I've found that just taking off the wheel and putting it back into the dropouts can screw up the disc alignment, though. You can sometimes correct the problem buy pulling on the quick release lever, wiggling the wheel, and tightening it back up.

Good luck!

-Dave

I read on another post to try business cards, I think I'll give that a try. The rub is BARELY there, I can even see light for the bottom 3/4 of the pad. But as you say, even without messing with it, it should be fine to ride.