Brake problems

[raildogg]

Hello, I've been having brake problems after getting the rear brakes replaced recently. The rotors were turned as well.

Here are some of the symptoms:

1. Loud grinding noises when coming to a stop very slowly. When the car is moving fast and the brakes are applied, the noise isn't there or it cannot be heard.
2. Sometimes there is a squeaking noise when brakes are applied.
3. These noises have only occurred after getting the rear brake job done.

After going back to the dealer to tell them the problems, they told me that they reexamined and brakes and didn't find much wrong. They did apply some more of the material that makes the noise go away. The car was taken for a drive with two techs sitting and they did hear the noise.

I was told that maybe replacing the rotors would fix this issue but they are not sure what is going on.

The car is a Mazda 3 sedan.

I would appreciate if anyone can offer some insight into this issue. I'm thinking of taking the car elsewhere to have it looked at but I've generally been happy with the service from this dealer up to now. Not sure.

Thanks.

 

[boomerang]

Based on your description my guess would be that the rotors were not properly refinished. The surface is rougher than it should be. When rotors are turned there should be a non-directional finish applied although few shops actually do that preferring to take very small cuts at slow feed on the final pass to get as smooth a finish as possible.

IMO, the problem will eventually correct itself. It will take some time though because the rear brakes provide a considerably smaller percentage of braking than the fronts. Your choices are to wait it out or replace the rotors.

 

[Puffnstuff]

Did they give you any instructions for seating the pads? Normally it involves several stops from 60mph to bed them to the rotors but each manufacturer is different. Are the pads stock or aftermarket?

 

[Quiksilver]

Most brake noise that I heard that are not caused by simple wear and tear of pads are improper fitment of abutment clips or the anti-rattle clips (if you car has em, not all do.) You see once rust, dust, and debris start getting into the clips the ears on the brake pad may stick in the corners and the result will be noise. I'd be curious if the cleaned everything and not just sprayed brake cleaner on it and called it a day. If the debris/rust build up is bad enough you might need to sake a flat file to the adapter and file some that rust off plus replace the abutments clips.

If that doesn't fix it the next thing I'd look at is the caliper pins and whether they are sticking in the boots from build up or not enough silicon (right? I cant remember if that the right stuff atm.) grease. If there a lot of build up it might be worth while to clean the pins, reapply fresh grease, and replace the boots.

The other thing I can think of was mentioned above, bedding the brakes. Not every place does this even if they do all the work 100% correctly.

 

[Raizinman]

Some dealers will offer a disc brake pad special for something like $99. This prices includes non OEM brake pads that are pretty cheap, noisy and dusty.

 

[mindless1]

If that doesn't fix it the next thing I'd look at is the caliper pins and whether they are sticking in the boots from build up or not enough silicon (right? I cant remember if that the right stuff atm.) grease.

Yes, silicone to resist thinning at elevated temperature. If a prior owner goofed and put regular petroleum grease in, it ought to be completely cleaned out and replaced with silicone grease.

 

[Puffnstuff]

Well I see the OP never returned to this thread to follow up on his post. If the nose persists I'd pull them apart and give them a thorough cleaning making sure that no rocks or other contaminates were trapped between the pads and the rotors plus make sure that the shims were there if needed. I don't know about Mazda but on my Toyota it had several shims on the backside of the pads that would cause chatter if missing with the stock pads.

 

[JEDIYoda]

No ,th OP probably bought a new car.....solved the problem!

 

[ra1nman]

I was curious to see what the root cause myself....