Question

Anormal brake wear

Hello,
I own a 2015 Mazda 3 sport 2.0(skyactive). I'm working on changing the brake pads and noticed some abnormal wear. The rear brake pads are unevenly worn off and the rotors is severely grooved. I got new rotors and brake pads but I can't compress the caliper piston. It's one that needs to be screwed in. I use the universal box that I've put on a ratchet and I'm trying to screw it back it, but it just spins and won't compress. I'm hoping ai

Discussion is locked

Answer
Follow
Reply to: Anormal brake wear
PLEASE NOTE: Do not post advertisements, offensive materials, profanity, or personal attacks. Please remember to be considerate of other members. If you are new to the CNET Forums, please read our CNET Forums FAQ. All submitted content is subject to our Terms of Use.
Reporting: Anormal brake wear
This post has been flagged and will be reviewed by our staff. Thank you for helping us maintain CNET's great community.
Sorry, there was a problem flagging this post. Please try again now or at a later time.
If you believe this post is offensive or violates the CNET Forums' Usage policies, you can report it below (this will not automatically remove the post). Once reported, our moderators will be notified and the post will be reviewed.
Comments
- Collapse -
Answer
Brakes

Hi, Alex; Yes, the caliper piston must turn, usually with a bit of down-force at the same time. There is, of course, the possibility that the caliper is 'frozen'. That would also explain the uneven wear. Reman calipers aren't very expensive, and some come 'loaded' with pads. Each time you use your e-brake, the pistons rotate outward to take up any slack in piston travel, but not overtighten.
Good luck.
Loren

- Collapse -
Answer
rust

Sometimes the piston can get a small bit of rusted spot on it, or more often the cylinder it fits in. That can cause it to stick, often while against the brake disc. If that happens, and in the rear, you may not smell the burning like from front brakes. Removing the piston and rehoning the cylinder, if the rust spot isn't too large, sometimes that part can also be slightly brazed and polished down. Most often today they just opt to replace it.

If there is no rust involved inside the cylinder or between it and the piston, you can use a large "C" clamp to press the piston back into the cylinder. That's what I do, and open the bleed valve slightly at the same time, to aid any air removal in the brake line. Close the bleed valve before releasing the C Clamp when piston is fully back in the cup's cylinder.

CNET Forums

Forum Info