Hi folks.
Son has a 77 Vette that has lost brake pressure. Master cyl. Is full and I've found no leaks anywhere. Soon as we start the engine the pedal goes right to the floor.My first guess is the vacuum booster. He's recovering from a foot injury in Quantico right now but will be able to drive again soon so I'd like to be able to get it going for him.
Thanks in advance for any suggestions.
copen

Hi folks.
Son has a 77 Vette that has lost brake pressure. Master cyl. is full and I've found no leaks anywhere. Soon as we start the engine the pedal goes right to the floor.My first guess is the vacuum booster. He's recovering from a foot injury in Quantico right now but will be able to drive again soon so I'd like to be able to get it going for him.
Thanks in advance for any suggestions.
copen
The brake master cylinder, not the booster, is bleeding past the seals internally.
Replacing the brake master cylinder and flushing the entire hydraulic system would be my recommendation.
Symptoms of a failed vacuum booster would be a high, hard pedal. The pedal wouldn't fade to the floor and braking effort would be quite high.
Only if the brake master was leaking from the rear seal would fluid loss become a factor.
Most shops that do brake work will do complete brake system inspections, including checking for pad wear, often at no charge. They hope that if a problem is found, you will buy the repairs from them. Have you're a local shop do a thorough diagnosis and write an estimate.
I hope this helps.