Just bought a 69 Z28 which has had everything replaced in the braking system, ie., lines, master cylinder, booster, etc. When the pedal is depressed once, the brakes work fine, but if let up and engaged again, the pedal goes very low and is hard to get any braking. This car has only the front power brakes and drums on the rears. I was told that this is a common Z28 problem, due to the 30/30 cam which doesn't produce very much vacuum. It also has stainless steel brake lines. Any thoughts?
