brake pedle stays hard

[n4itb]

I just got my 88 toyota supra turbo running in the brake pedal stays hard now. what could it be the car is at the exhaust shop right now so I can't take a look at it till monday. When I took it to tthe shop they stayed hard till they got hot then they went to the floor. I let off and pushed them again and they were back hard please help don't know what this could be

 

[hvyman]

Possibly a bad booster.