Quote:
Originally Posted by pesarirany
I have recently Purchased a 2017 BMW M3 with only 40K Miles. The previous owner had changes the rotors to ceramic rotors possibly rotor size is 500mm
I just picked up the car and as I was driving it I noticed at 60Mph when you push brake the whole vehicle shakes bad and pulls to the left.
I took it to my mechanic and we checked and made sure everything was tight on the rotors ( I had this issue once and we noticed it was just loose on another car)
my mechanic mentioned that the brakes has recently changed because the pad is like literally brand new.
I am trying to see if anyone here would know what could possibly be because I really like the car and I want to drive it a little before I sale it
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Did you ask your mechanic why the brakes were acting they way they were?
Shaking suggests a problem with the brake rotor surface. I don't want to say "warped" brake rotors but the rotor (both rotors) should be checked for in spec parallelism and runout.
My only experience with pulsing brakes came from uneven pad material deposition rising from an emergency stop from speed with rusty cast iron rotors. I didn't know this at the time so I checked the rotors for in spec parallelism and run out. Both were well within spec.
It could be possible for ceramic rotors to be at risk of uneven pad material deposition albeit though not from rust being present.
Pulling to the side suggests uneven braking action of at least the front brakes. Couple of explanations is a brake hydraulic line pinched or a stuck piston which results in the affected brake not producing the same braking force as the other side the good side.
With a 2017 I have to wonder when was its last brake fluid flush/bleed and one that includes proper cycling of the ABS pump?
While I have done the brakes -- replaced pads/rotors even did fluid flush/bleed services -- on a number of cars over the years the few times when the braking system manifested issues not related to normal brake wear I had the vehicle in to the service department. With 2 vehicles both were still under new vehicle warranty. In both cases the problem was brake fluid related and a proper flush/bleed was the cure. In the case of my JCW the fluid service was not over due. In the case of my Metris van the fluid service was sort of due. But the van sat outside some time on a dealer's storage lot before I bought van and this exposure resulted in accelerated degradation of the brake fluid.
The brakes are a safety critical system. So my advice is to have the vehicle in for this braking behavior.