6

I just got delivery of a road bike with SRAM Red disc brakes. It was delivered with little inserts in the brake pads to prevent accidental squeezing of the lever when the rotor was not in.

When I put the wheels on, I noticed that the pads were too tight on the rotor even in the released position, so they were rubbing heavily (not because of misalignment but because of being too tight.)

So I did what I read online:

  1. Removed the wheel
  2. Removed the brake pads
  3. Gently used a flat-head screwdriver to push the pistons back in (the best I got was so that they were flush with the body of the brake caliper)
  4. Put the pads and wheel back on.

Unfortunately, when I squeezed the brake lever again, I could feel that the feeling got firmer and firmer for 2-3 squeezes, until, again, the brake pads would not recede from the "braking" position, and be in contact with the rotor at all times.

What can I do to fix this?

6
  • 1
    Are the pads actually in contact with the rotors now? Do the wheels spin freely? Hydraulic brake pads do not retract very much and may look like they are contacting the pads. Mar 22 '19 at 23:12
  • Yes, it's a very heavy rubbing. The wheel won't spin half a turn if I push it with my hand. Mar 22 '19 at 23:25
  • 3
    Try aligning the calipers? Also try riding the bike and doing the pad bed-in procedure. Mar 22 '19 at 23:27
  • @ArgentiApparatus done that and didn't help. I even took it to a bike shop and they could not fix it! Said that the pistons will not recede properly after the brake levers are released. Sounds super weird to me, with brand new SRAM Red calipers. Mar 27 '19 at 9:21
  • 1
    @SalvatoreIovene I've had 2 sets of Avid (SRAM) brakes fail this way, and my lbs gave the impression it is fairly common. Since yours is new, I would look to get the caliper replaced under warranty.
    – Andy P
    Mar 27 '19 at 14:18
6

My avid brakes had the same problem and it was due to too much fluid in the system, to solve the problem :

  1. Remove the pads and keep them away from any oil (fluid).

  2. Unscrew the bleed screw a little and put a towel on it

  3. Push the calipers back completely

4.Clean calipers well before reinstalling pads.

Be aware that the amount of fluid that will exit should be a drop or a little bit more. Let too much fluid exit and you will have to rebleed them, so do it gradually.

This is a common problem on new avid sram brakes.

5
  • 1
    +1 this is something I would try on my own bike, because I’m confident I could spot if I messed it up. Otherwise I’d have the shop do it.
    – Swifty
    Mar 27 '19 at 20:14
  • 2
    Maybe suggest explicitly to remove the pads first of all and keep them away from any oil (fluid). Clean calipers well before reinstalling pads.
    – Swifty
    Mar 27 '19 at 20:15
  • 1
    Thanks, I did exactly that. All it did is that now the brake lever needs to travel farther, in order to activate the pistons. But in the rest position they remain too tight and rub. Mar 28 '19 at 9:23
  • 1
    @SalvatoreIovene if it didn't solve your problem you will probably have to go back to the shop that sold them to you and have them repair the brake(or replace them under warranty). Mar 29 '19 at 11:59
  • Note that SRAM brakes use automotive DOT brake fluid, not mineral oil. The stuff is more toxic and eats paint. More caution than just “clean well” should be exercised.
    – MaplePanda
    Jun 24 at 3:44
2

I released a few drops (4) from the lever. that solved my issue. held lever in and slowly unscrewed bleed screw. Kept lever pulled and after a few drops evacuated turned bleed screw back in. then released lever. perfect.

1
  • Hi, welcome to bicycles. Please note that there is already a more detailed answer that suggests doing this. It's good form not to post new answers unless you have something additional to contribute that's not covered in any existing answer. You might want to take the tour.
    – DavidW
    Jun 24 at 15:10
1

It sounds like you reset the caliper piston correctly. Most hydraulics will automatically set the brake pad distance as you cycle the brakes. This is why it got firmer and started rubbing.

Next I would look at caliper alignment. Disc brakes have tight tolerances (i.e., the pistons only retract a short distance). If the caliper is not correctly aligned parallel to the rotor, part of the pad will touch the rotor, especially if the rotor isn’t perfectly true. Generally, you release the caliper fixing bolts, until the caliper can move, engage the brake firmly (to center the caliper on the rotor), then re-tighten to fixing bolts. Use a flashlight to check then alignment, there should be an even gap between the pad and rotor on all sides.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.