Grinding noise left rear wheel

Tiny
JEAND
  • MEMBER
  • 2003 MAZDA 6
  • 2.3L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 138,000 MILES
Hey 2CarPros,

I recently changed my rotors, brake hardware and brake pads on my car. When test driving I noticed a grinding noise coming from the rear left side wheel. It would really only be heard going at low speeds, and would on intermittently. I examined the old braked pad and noticed one side had worn very very unevenly. So I took it apart greased the caliper guide pins. Made sure they moved smoothly and test drove again. Same problem. Just bought a new caliper and bracket assembly with new guide pins. Still having the same problem. Also, the noise doesn't stop whether I brake or not. Any suggestions?
Wednesday, July 17th, 2019 AT 8:31 PM

95 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Welcome to 2CarPros.

Did this noise just start since the brake work? Does it change pitch when turning, coasting, accelerating or anything you can think of?

If it just started and nothing changes it, first check to make sure the backing plate behind the rotor wasn't bent and is rubbing the rotor. Remove the wheel and move the rotor back and forth to see if you can identify where the sound is coming from. My guess is that it is touching and making the noise. If nothing is toughing or hanging up, I would recommend returning the brake pads and trying a different set. I have had situations with less expensive pads that made noise no matter what I did. I don't know if it was the compound used, but nothing would get rid of the noise.

Let me know if this helps or if you have other questions. One last thought, make sure the parking brake isn't too tight and hanging up.

Let me know,
Joe
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Wednesday, July 17th, 2019 AT 9:26 PM
Tiny
JEAND
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Yes, it just started after the brake work. I tried everything, it does not stop no matter what I do. They are good brakes, I do not think they are the problem. The dust shield was my guess as well. I just bent and pushed it back a little and drove it before seeing this the email. The noise has gotten noticeably lower in sound and frequency. The dust shield wasn't bent but could it be that the new rotor is slightly thicker than the old worn one I had which could lead the the rubbing/grinding sound? I might just remove the dust shield altogether. What do you think?
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Wednesday, July 17th, 2019 AT 10:04 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Welcome back:

The rotor should be a little thicker, but shouldn't touch. You may have accidentally bent the backing plate. See if the noise stops if you bend it away more. I don't recommend removing it. It has a good purpose. It keeps all the junk from under the vehicle (while driving) from covering the rotor.

Let me know if that takes care of it.

Joe
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Thursday, July 18th, 2019 AT 6:11 PM
Tiny
JEAND
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  • 62 POSTS
I just came from my car before seeing this message. I took off the wheel and jacked it up in the air. Spun the rotor and heard the grinding noise. The dust shield is not touching it from the back or the sides so I took the caliper and caliper bracket off. When I spun the wheel there was no noise coming from it. I put the caliper bracket and caliper back on with the brake pads installed and spun it hearing the grinding noise. So I took the brake pads out and spun the wheel. There was no noise at all. The caliper is not coming out uneven and is brand new so now I am lost. Any suggestions?
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Thursday, July 18th, 2019 AT 6:44 PM
Tiny
JACOBANDNICKOLAS
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Are the pads floating in the caliper? In other words, when you have them mounted, are you able to move them at all or do they seem frozen in place.

Next, if they are free, what kind of brakes did you get. I have a feeling it is the brake pads. Also, is there anything on the mount, caliper, or rotor that indicates something is rubbing?

Let me know.

Joe
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Thursday, July 18th, 2019 AT 6:52 PM
Tiny
JEAND
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  • 62 POSTS
The only thing that was rubbing was the brake hardware Wich I remove and shortened with a dremel. Also, the pads on both the right and left side wheels would not go on without shortening the ends of the brake hardware.

If I lift the caliper the brakes are easily moved, and would just drop out of the bracket if I nudge them. I lube my brakes well.

I bought the *Power Stop Evo* rear brake pads. I think they were bout 17 or 19 bucks.
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Thursday, July 18th, 2019 AT 7:11 PM
Tiny
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Welcome back:

I'm not sure why the hardware needed shortened. Are you certain the are the correct brakes for the vehicle? And I'm not familiar with the brakes you used. If there is no noise with them off, that is the only thing I can think of. Is it possible to return them and get a different set or brand? Also, is it possible for you to record the noise you are hearing and upload it for me to hear?

Sorry for all the questions. Not being there causes me to think of all types of possibilities. As far as the hardware, in over 35 years or working on vehicles, I never had to shorten the hardware to fit. Did you compare it to the old hardware?

Let me know and sorry if I'm being a pain. LOL

Joe
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Thursday, July 18th, 2019 AT 7:17 PM
Tiny
JEAND
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Thank you.

Lol you are not in the least being a pain. Yeah, I have never had to shorten hardware before as well. Uhm, yeah I think I compared them.

I have another set of hardwares that came with the caliper I will try. The funny thing is that the other side isn't making any noise. That's what is weird to me.

I can try to get the noise on audio. It might be hard to hear though. If I can get it I will send it.
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Thursday, July 18th, 2019 AT 7:36 PM
Tiny
JEAND
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It won't let me upload the recording. Is there another way to get it to you?
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Thursday, July 18th, 2019 AT 7:57 PM
Tiny
JEAND
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  • 62 POSTS
Also, I notice the grinding sound I there most when I am taking a corner now.
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Thursday, July 18th, 2019 AT 8:06 PM
Tiny
JACOBANDNICKOLAS
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Welcome back:

Are you sure it isn't a wheel bearing?
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Thursday, July 18th, 2019 AT 9:09 PM
Tiny
JEAND
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  • 62 POSTS
If it is I will be mad. I don't know though. If it is, shouldn't it make noise whether the brakes are installed or not?
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Thursday, July 18th, 2019 AT 9:14 PM
Tiny
JEAND
  • MEMBER
  • 62 POSTS
I just notice the the brake pad is loose in the caliper, as in I can easily wiggle it with two fingers. The other ones I cannot. They are tight. Could that be the culprit?
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Friday, July 19th, 2019 AT 5:26 PM
Tiny
JACOBANDNICKOLAS
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Welcome back:

Yes, that could be the issue. Remove that brake pad and see if the sound is gone. I have to be honest, I question if something was mixed up in the packaging because you really shouldn't have had to modify the hardware.

Let me know.

Joe
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Friday, July 19th, 2019 AT 7:01 PM
Tiny
JEAND
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I'll try that in the morning and see if that makes a difference. Because that pad doesn't seem to be positioned right like the others.
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Friday, July 19th, 2019 AT 7:28 PM
Tiny
JACOBANDNICKOLAS
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Welcome back:

Make sure to check size, design and all. Something is most likely different. Also, if you could upload a pic of the hardware you modified, and how it was done, it may help me.

Joe
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Friday, July 19th, 2019 AT 8:09 PM
Tiny
JEAND
  • MEMBER
  • 62 POSTS
So I think that the brakes are defective for one side. I put in the new brake hardware and it is still jiggling. The sound is there too. Since the sound is inconsistent it has to be the brake pad. When it moves it runs and then comes off then back on. I uploaded the video with the brake hardware modification. Turns out I was trying to put them on backwards like an idiot. I put on the ones that came with the caliper. The brake pad seems to be too small.
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Saturday, July 20th, 2019 AT 12:06 PM
Tiny
JEAND
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Here is the video of the brake wiggling.
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Saturday, July 20th, 2019 AT 12:13 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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I agree with you. Something is wrong. I wouldn't expect to see that much play. It's good they are not stuck or frozen in place, but that seem excessive to me.

Honestly, I would start over with a different brand of brake pads. If you have the hardware that came with the caliper, just use those. Don't be surprised if the problem is the composition used in the brake pads themselves. I have experienced that in the past.

Let me know what you find.

Joe
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Saturday, July 20th, 2019 AT 9:29 PM
Tiny
JEAND
  • MEMBER
  • 62 POSTS
Yeah I'm just going to go and get some akebono brake pads. I know they are superb quality. Thanks for all your help by the way. I really appreciate it.
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Saturday, July 20th, 2019 AT 9:40 PM

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