Funny brake noise

[Sawdusted]

Guys, I have a noise coming from what I think is the brakes. Please help me diagnose the problem. Patient is a 2001 Nissan Pathfinder.

Faint grinding noise when the brake pedal is depresses, usually at light to moderate braking when the car is relatively slow, anywhere between 5 to 15 mph. It sounds like the brake releasing or my ABS kicking in but the roads are dry asphalt. Could it be a bad abs or wheel speed sensor? The ABS light is not on though.

A little more history. Just had 1 front caliper replaced together with new pads and rotors on the front. It worked fine for about a week before the noise started happening.

Thanks!
Julian

 

[Towncivilian]

You can try running ABS self-diagnosis described on page BR-41 of the factory service manual. You should also be hearing some mechanical noise and/or feeling the ABS self-test when you first reach 4MPH in any direction, if this is not the case then there is likely something wrong and hopefully self-diagnosis will detect it.

Does the "ABS" light illuminate for a second when you first turn the ignition to "ON"?

What brand of pads, rotor, and caliper did you use? Did you bleed the system? Lubed the slide pins sufficiently?

 

[Cardenio327]

Probably not related to the brake noise you're hearing, but why would they have only replaced one caliper?

You might have different piston materials now, i.e. phenolic plastic or aluminum on one side and chromed iron on the other side! To me that would make the thermal characteristics different from side to side, allowing one side to heat faster than the other, making one wheel brake different than the other.

Also, why was the caliper replaced? If it was replaced because it was sticking or stuck, it is just a matter of time until the other one ends up in the same condition.

Replacing only one caliper sounds like the quality of work a body & paint or collision repair shop here in Mexico would do. The noise is probably due to some other error on their brake job.

Maybe have both calipers replaced at the same time next time.

 

[Sawdusted]

Guys, thank you for the replies.

The L/F caliper was replaced because it was sticky and the right was working ok. My extended warranty didn't want to cover the other caliper since it was working fine. I will try to fight them to cover the R/F too.

Matt, if I am reading the FSM correctly, the self diagnosis is only for when the ABS lamp is lit. Will the self-diagnosis mode also work for when the lamp is not working?

Julian

 

[Falken]

I would prefer two new front calipers as well.

Wheel cylinders on rear drumms, only one replaced is fine with me, they don't heat up like calipers, they just push outwards on the shoes and with much less force required due to "servo action" where the two shoes bind and jam in the drum to increase breaking force.

I have a feeling you just got a scrap brake job done.

I would have to pull it apart to see what was done poorly. It could be something simple like the pads need moly grease or anti-squeek applied to the shims.

Maybe the slider pins are dry with no silicone grease applied and the braking force is uneven.

I like to clean the hub surface before putting on the new discs with a thin coat of anti-seize on the hub surface that contacts the inside of the "hat" of the disc.

This helps ensure rust build up isn't increasing runout with an even rust free base to work off of.

Maybe the caliper that was replaced has air trapped in it and needs to be bled properly...

You just got a newb brake job done I'd guess.

 

[Sawdusted]

Falken, the rotors are captive rotors. Not so much an issue on rust on the hat of the rotors.

 

[lugNutz]

Pull the ABS relay and check the operation after. Not sure if I missed it somewhere, but are you getting pedal pulsation?

 

[Towncivilian]

On second thought, the preliminary check described on BR-50 and following is a better place to start. I did not find a "system OK" code flash in the list, so perhaps self-diagnosis will be useless without the ABS light lit.