Brake grind?


#1

2011 infiniti. new rear rotors/pads 6k miles ago. now there is a rythmic sound with very slow speed braking. like a bad spot on 1 rotor. you hear a grind, stop, grind, stop. its not a constant grind sound. i looked at both rear rotors thru rim slots. rotors look perfect. very smooth. i have not pulled wheels to check. i am thinking rotors making sound vs pads making sound. but why would a rotor have an odd spot or rough patch? there is no ridge at all on rotors. cant see the pads rubbing on some rust ridge? there is none


#2

The most likely culprit is a backing plate that got bent towards the rotor when the brakes were done. Pull the rear wheels and make sure the backing plates are not too close to the rotors. If they are you can gently bend them away a little.


#3

true. rotor is new. caliper is mounted to caliper bracket. so caliper is straight. only thing that could be out of position is the flimsy backing plate. but you would not think a new clean rotor would make a hit/miss/hit sound on backing plate. you would think it would be constant grinding. i will take off wheels and look


#4

Car had flat tire today. Put on spare. Did not look at rotor. It’s raining.


#5

It could have been seperating belts on the tire, did the issue go away?


#6

we rented uhaul today. kid says uhaul truck has SMOOTH feeling brakes. sez infiniti has rough feeling brakes. all 4 pads are ok, depth wise and rotors look fine. car has 50k miles and rear rotors were replaced 6k miles ago. but, owner is not sure if rear pads were replaced. shop sez rear pads are at 15% left so i would say no. going to try different ceramic pads since car is spec’d for ceramic.


#7

Roughness in the brakes is usually caused by the rotors, not the pads. I just changed the front pads and rotors on my 04 Sienna yesterday. The old pads were in great shape and the rotors were worn but looked smooth. I had a bad vibration in the brakes before I switched them and now they are smooth as can be. After 55,000 miles of hard service the old front rotors were just not as smooth as they looked. The only true test of rotor smoothness is a run-out test (or a simple replacement).


#8

Well, is replacing all pads with new, oem ceramic pads a waste of time if we do nothing for rotors? I scratched each rotor with my fingernail and rotors feel smooth. Look great too.