Brake pedal to floor, piston bottoming

[Gordon Sauer]

Had the two servos rebuilt made sure the pressure differential valve was centered and put it all back together and the car does stop but it clearly feels like the piston is bottoming out in the tandem master cylinder and no matter how hard I press the brakes with engine off, I can’t stop the rear wheels from turning when I’m trying to undo the Nader nuts – can this just be air in the system, and there’s no loss of fluid or anything? And I have bled the heck out of it and put in one way bleed screws. Thanks Gordon

[alaric]

Hi. I had a lot of brake pedal travel, no matter how much I bled the system. I had two problems. First the union nut on the pipe that exits the servo was rounded off, and I couldn't tighten it more. I found that I could move the pipe slightly in the joint to the servo, so figured it may be allowing air into the system. So, I replaced the pipe from the output of the servo to the junction that's to the right of the steering rack. So, that was a leak.

Second was front wheel bearing play - I had a lot of movement on one side when I grabbed the top of the wheel and rocked it sideways. The larger the movement, the further the pads will be forced from the disc when the car is driving along. With my car I found that the pedal travel was ok until I moved the car. Adjusting the bearings reduced that increase of pedal travel.

Regards.

Sean.