'72 disk brakes help

[Kevin1972C20]

I have recently purchased a '72 c20 with 4 wheel disk. The truck stops but not quick and with alot of effort on the pedal. I am looking at possible bad master cylinder but this is only a guess. Pads are in good condition, rotors are clean and it doesn't pull when braking. Fluid change might help but that can't be causing the issue.
Any advice on this?

Thanks,

[cparman]

what kind of disc brake calipers are on the rar of the truck?

[mycool72]

I believe the booster runs off a vaccum. Make sure that line is secure to the back of the carb..mine had a small leak...simply put-leak=no brakes.

[Kevin1972C20]

Thanks Cool72, my vaccum line were pretty bad so I checked and was only getting -4 pressure. replaced the lines and am around -10 to -14 now. Havent check to see if that did it yet. Since the wheels are off I decided to play with the suspension a bit... who knows what I'll find.

[SCOTI]

Originally Posted by Kevin1972C20

Thanks Cool72, my vaccum line were pretty bad so I checked and was only getting -4 pressure. replaced the lines and am around -10 to -14 now. Havent check to see if that did it yet. Since the wheels are off I decided to play with the suspension a bit... who knows what I'll find.

Vacuum boosters require about 16-17" minimum to be completely effective. That low vac. you indicated would definitely contribute to lower pressure being applied.