Chevrolet Repair: Power Brake Booster, power brake booster, booster valve

Question
1984 Corvette. The car has been sitting for about 8 years. I had it towed to my home. It is now running. New master cylinder and brake pads. The calipers work(not stuck). The brakes seem very hard to stop the car. I have only tried in the driveway due to poor braking. I suspect a bad brake booster. I do get a hard brake pedal. I have suction at the booster valve and in only one direction.
The pedal does not move when depressed and the engine turned off. Just looking for a second opinion. Seems to me to be a bad brake booster. Your opinion?
Thanks
John

Answer
HI JOHN, NOW YOU ARE TALKING. IS IT GOOD SHAPE ?? I HAVE 2010 ZR1.I LOVE IT...OK,GETTING TO YOUR QUESTION. WHAT I WOULD DO FIRST IS REMOVE THE VACUUM TO THE BOOSTER AND PLUG THIS LINE. START IT AND SEE IF THE BRAKE PEDAL IS AS HARD. IF SO THEN I THINK WE HAVE A BAD BOOSTER OR THE CK VALVE GOING INTO THE BOOSTER IS BAD. I HAVE SEEN MANY OF THESE CK VALVES GO BAD. START THE ENG AND PULL THIS HOSE OFF GOING INTO THE BOOSTER, MAKE SURE THERE IS GOOD VACUUM PAST THIS VALVE. THEN CK THE HOSE WITHOUT THE VALVE IN IT AND THE VACUUM SHOULD BE THE SAME..THERE IS NOTHING ELSE LEFT IN THIS SYSTEM TO CK..THE WAY YOU ARE TALKING IT DOES SOUND LIKE A BAD BOOSTER..GOOD LUCK AND IF YOU NEED MORE INFO GET BACK TO ME.. PLEASE WHEN LEAVING THIS SITE WOULD YOU MIND RATING MY ANSWER, THANK YOU ,,,TOM..