Brake surging

Dave writes in about a brake pulse: Hi Mark, David here: I have problem with mothers Lincoln 97 town car that has a brake surge. I turned the rotors a while back and new pads installed also about 2 months ago.

When we go to brake the car surges on and off, can’t explain it. It feels like it hesitates, but we stop fine. I took off the front tires and checked the rotors and shoes. The rotors were smooth with no bluing and plenty of shoes remaining.

I don’t have an idea what the brake pulse is all about? Could there be air in lines causing this surging or what? Is the booster going bad? Maybe the calipers are hanging up? Should I try relubricating the caliper slides? They have not been greased since the front pad replacement.

Let me know what you think. I do not feel it at the brake pedal as the pedal does not jump. It feels like something is out of round. This is the best I can explain without you driving the car. But again the car stops fine. More brake surge action happens at higher speeds it seems, but we stop fine.

Thanks from David

Hello David: Tough one without driving it! In most cases any brake surge is caused by warped rotors or drums. But you usually feel it in the brake pedal along with the car surging (but not always).

Also after you remove material from the rotors they are more susceptible to warping! Especially if these are the original 12 year old rotors and may have been turned more than once.

I am leaning toward rotor replacement but if I had your car in my shop with the wheels off I would mount my dial indicator on the rotor to measure the amount of run out on the face of the rotor to confirm this before replacement.

Thanks for the question
Mark

Mark, David again: Thanks for the push in the right direction and help with my brake pulsation problem. They were the original rotors and have been turned several times. I replaced the rotors and for good measure I put a new set of front pads on as well.

The good news is the surging is gone and my mother is happy to drive her Town car again. I think it was worth the money since the car has low miles even though it is a 1997 and 12 years old. My mother loves this car and the longer she wants to drive it the better!