My 71 bus is giving me some weird brake problems. When I first start the bus and hit the brakes for the first time, the pedal resistance is light and stopping is excellent... similar to modern power brakes. After this first press of the pedal, the pedal comes up a little slow, and the brakes feel hard and stopping power is diminished significantly. I practically have to stand on the brakes to get the bus to stop. If the bus not running the brakes are *really* bad.. so I know the booster is working at least.
I was told by the PO that the brake booster is brand new, and that the front calipers are also new. I looked underneath and they do seem shiny and new. I noticed when trying to adjust the rear brakes that on the right rear the adjusting stars are frozen in place and can't be adjusted. I'm planning to pull it apart in a few minutes to loosen up the adjusters.
My question is: On a bus with front disk and rear drum brakes what would cause the symptoms I'm seeing? Could one brake being out of adjustment cause this due to the pressure regulator in the system?
Thanks, Tom