Hi 61 C10 with stock standard brake system. All parts replaced including MC and wheel cylinders.
When stationary I have a good hard pedal with correct play. However as soon as the truck moves the pedal will drop nearly to the floor! It does not feel spongy then, but only catches when the pedal is nearly to the floor. Shouldnt the pedal feel the same when staionary or when moving? Should I suspect the MC or the wheel cylinders? No leaks and shoes are adjusted tight to the drums. Thanks for any ideas.
