Hard brake pedal and brake light stays on

Booster hose or check valve. Lack of vacuum pressure. Rear drum wheel cylinder is not moving or is frozen.

Have good vacuum pressure at hose just before the check valve. The check valve is also new came with the new booster. Car had been sitting for 3 years, replaced motor and drove it for for 5 days. The sixth day got in to go for a drive and didn't have any brakes. Pedal went to the floor. That is when we replaced the booster and the master cylinder.

Check your rear wheel cylinders for leaks or froze stuck, if fine check your front calipers.

Flush/bleed the brake lines, I am sure after sitting for 3 years you need new fluid. Check to see if there is a proportioning valve(s) after the master cylinder, it may be clogged, as-well as the hard plastic lines to front brakes maybe coming apart on the inside stopping/clogging fluid from passing threw. Check your sensor connector to see if there is a bad connection. Most likely a froze up wheel cylinder but if so that may not be why the light is on.

We replaced the brakes, hoses, bled brakes. Still hard pedal. We disconnect the vacuum line at the booster and had vacuum but not a lot. Disconnect the line at the other end of the line and found good vacuum. We blew air thru the line between the booster and block and found crap in the line. Took the line off the fire wall and removed the crap in the line. Reconnected and now we have brakes but the pedal is weird. You push the brake pedal it is a bit pushy then you push a little harder it gets stiff but then the brake light on the dash comes on. You release the brake pedal the light goes off. What could cause this?

Try doing this pump your brake pedal with the truck off until you cant push it down any more then push down on the pedal and hold it then start the truck, if the pedal does NOT drop you need a new brake booster. I am concerned if you have enough vacuum too. May need to check vacuum at booster line, and if you have a external check valve in vacuum line to booster test it too. If your check valve is in master cylinder, you can either rebuild it or replace it whole unit.

Goes without saying the crap in the vacuum line likely also went into booster before clogging up.