Brakes PLEASE HELP

[BBBAD86GN]

Guys/Gals
I have a 86 Gn with 41000 miles, here is my dilemma.
My brake light stays on and the power booster runs at all times.
I get about 15 to 20 normal pedal motions. The pedal gets very firm and the car does not want to stop.
I have replaced the accuator ball, brake sensor on the master cylinder and no luck. My fuses are ok and do not trip, fluid is good.
I replaced the rotors/drums/shoes and master cylinder also last year. I have a feeling its the power assist motor and need some good advise. I do not want to change the system to vaccume.
Im going nuts here, I looked at most of the posts and they are
confusing. I talked to a tech from Poston and he adivsed me to change the brake senor and or accuator ball.

H E L P......
Thanks for reading
RAY

 

[gofstbuick]

The master cylinder probably needs to be rebuilt. It's probably leaking past the check valve for the PM motor (in the master cylinder housing). Don't drive it too much or you'll burn the PM motor up. Try ordering a master cylinder rebuild kit from GM and rebuild your master cylinder.