On my 67 GMC 2wd, original manual drums
I installed an entirely new brake system
10 bolt rear out of an 82 chev tk, New CPP front disc calipers,hoses, rotors
New rear drums, shoes, wheel cylinders ,hardware, rubber hose, hard lines, 1/4" rear, 3/16" front,
Bought a new large Master cylinder, booster, prop valve kit for a 67-72 truck, it came with a firewall mounting bracket off ebay.
It had a fairly hard pedal and just wouldn't stop very well, the pedal would go down halfway and that was it, would just slow down and wouldn't pump up.
Changed the master cylinder, no difference, The booster quit working completely so I bought this setup,
https://www.summitracing.com/parts/sum-760197
Benchbled the cylinder and the pedal is a bit better, not great and the power assist is somewhat working, but it still just slows down, will not lock them up in gravel.
Will push fluid out the bleeders when pedal is depressed
On my last truck (61 chevy) I had to drill a new hole in the brake pedal to correct the ratio for the new power brake set up.
This has the linkage on the bracket between the pedal & booster and I don't see any info on pedal ratio for the 67-72's
I've had alot of these trucks in the past ( mostly built from junk)and never this much trouble or expense.
Any ideas would be appreciated
Thanks