My KP61 sat for 8 years before I bought it. I got it running and had a rock hard brake pedal. Bad booster I thought. So I replaced the booster, master, rubber lines front and back, drums, wheel cylinders, calipers and rotors. Same crap. Rock hard pedal. The new booster holds vacuum for days and there is plenty of it.
If I had a blocked or pinched steel line, wouldn't that also give me a hard pedal? I've been thinking that my new booster was defective, but it acts just as the original did. There is almost no stopping power and the brake pedal doesn't move much when the system is bled.
Has anyone encountered this?