ATE rotor warped
 

I replaced the front rotors and pads on the GLK in March of this year. 5,000 miles later and I had some pedal pulsing. Went to two separate indies and they both said that if you feel it in the pedal, its the rear, if you feel it in the steering wheel, its the fronts. So I had the second place replace the rears. I think it may have pulsed a little less but its hard to tell. So I ordered some new rotors and pads for the front. I should have gone with my gut. I knew it was the fronts that were bad.

I ordered some power stop rotors and pads which I put on today. Low and behold, no more pulsing in the pedal. Pelican has sent me an RMA for the rotors and pads. I do not have tools to measure the rotors but one of the rotors is a bit discolored. I am guessing heat may have distorted them a bit although I do not know how. Neither of us ride the brakes or drive aggressively. The wife yells (a lot) at other drivers but she does not drive crazy. Perhaps something was defective. I do not know.

This is the driver front and you can see some of the discoloration.
https://lh3.googleusercontent.com/jS...=w1268-h950-no

Here are the new Power Stops.
https://lh3.googleusercontent.com/56...=w1268-h950-no

Did you break them in?

yes. A few stops from 50mph or so and then cruised around for a few miles. I would think if there was an issue with the brake in the warping would have manifested itself before 5,000 miles passed.

you wheel bearings/hubs are good.

could be a sticking caliper. go for a drive and afterwards using a laser thermometer check for temp at each wheel.

We are two people with four to six cars at any given time. Some cars are idle for weeks. With idle cars, moisture causes rust spots on the rotors, especially under the pads. That pretty much ruins them. It's been cheaper to buy Chinese replacement rotors, but with prices going up, I may start turning them again.

Bearings felt good. Both calipers floated fine without any resistance when I took them off. I do not have a thermometer but the car stops straight as an arrow.