Hello,
I'm having a problem with a 74 I picked up this spring. The rear brakes are practically not working. The front brakes work great. I get a lot of travel in the pedal and it seems soft. I replaced the rear calipers as one of them was hissing and bubbling brake fluid. I've bled the system both with a vacuum pump and manually. The master cylinder looks very new, but I'm not getting much fluid out of it for the rear brakes when I crack the line open and depress the brake. Could this be a booster problem, I think it's the original? Or is a bad master cylinder more likely? Any insite would be helpful.
G