Weird brake issue- '85 300D - PeachParts Mercedes-Benz Forum

ROLLGUY · #1 02-27-2017, 08:34 PM

My niece was driving their extra car ('85 300D) home a while back. She pulled over because the car did not have enough power to climb the grade on Cajon Pass (3,500'). It seemed like the rear brakes were on. When she stopped, she noticed that the rear brakes were smoking. She had the car towed home. A couple days later, my brother drove the car and everything worked fine. A couple days after that, he drove it and noticed the pedal going to the floor and barely stopping. He had the car towed to my house yesterday. I noticed brake fluid leaking from both rear calipers, so I replaced them with a pair of good used ones. I also put on a pair of turned rotors as well as new pads. Now comes the weird part. I successfully bled the rear brakes, and moved to the front. When doing the passenger side, I noticed (heard) bubbles in the fluid reservoir. I was able to get all the air out of that side, and moved to the driver side. I noticed the same bubbles in the reservoir when pushing down on the brake pedal. After bleeding the brakes, I test drove the car. It seemed to stop just fine. I was able to skid the front tires, and I imagine that the rears will get better as the pads wear in. However, the bubbles still concern me. Could there be something amiss with the master that would have caused the rear brakes to lock up in the first place? I will probably just replace the master for good measure anyway. I just don't want this to happen again......Rich