Hi all,

I tried a search to answer this question to no avail: I just replaced my front pads and rotors. I went with Brembo rotors and Hawk ceramic pads. After changing them and bedding them in per the Hawk instructions, I have a pulsating noise coming from both sides (it actually became apparent right away when I was bedding them). I took the calipers back off, put more brake lube on, and still the noise is there. The harder I brake, the worse it is.

Any thoughts on what this could be?

Other facts: the last rotor/pad combo was Brembo and EBC Greenstuff. I installed those as well, and had absolutely no problem.

Thanks!

 

Is the mounting surface that the rotor touches on the hub clean? If you have a bit of rust or other crud there it could cause your rotor to not seat properly. That could cause the warped rotor symptom you are feeling.

 

I'd check that both rotors are fully and cleanly seated on the hubs. The rotor were well cleaned with brake cleaner or good soapy water to remove any oils to preserve them. And if they were plated that the zinc is not now smeared into the pad from the bedding.

Depending upon the ceramic compounds, over heating of the new pad can cause some pad smear as well. This will be evident by any hot spots on the rotor from your bedding hard and then parking the car post bed, while still very hot.

 

Crashton and Toddtce, thanks for you replies. I did clean the surface prior to mounting the rotors, but also put a thin coat of lithium grease on the hub prior to mounting the new rotors. Could this the be problem? (although I did this the last time I changed the rotors, too).

If in fact the problem is due to hot spots on the rotor, will the pulsation go away with more miles?

 

If it is hot spots it's my belief that you may have to turn those new rotor to get rid of them.

If it is pad smear it may or may not wear away. I'd try cleaning them with brake clean & a scotchbrite pad. I'd try this first, before more drastic measures.

 

Thanks Crashton. I just drove the car under normal conditions, and felt no pulsating. If I hear the noise again, I will do the brake clean/scrub method you suggested.

As far as I know, the brake system has never been bled or purged (I have 70k currently, bought it with 25k miles). Is it time to have this done (regardless of whether it will help the pulsating)?

 

Dave, you are way past time to change out that old funky brake fluid. It won't do a thing for your brake pulsing, but it will raise the boiling point of the fluid making your braking system safer.