Greetings. I have a 1967 Olds Delta 88 with power brakes and drums. When the car is not running, I have a brake pedal. When I start the car, the pedal goes to the floor and makes a "whose" sound. It has plenty of brake fluid. Any idea? Thanks

 

It sounds like your vacuum booster has a leak.

 

You can test the vacuum booster by depressing the brake pedal with the car OFF and starting the engine. The brake pedal should pull to the floor with the car running.

 

Thanks so much for the response. If the pedal goes to the floor when I start the engine, then that would show a vacuum leak. I will check the vac hose. If it's not the hose ,is there a repair or should I replace the booster? Thanks.

 

No, if the pedal goes to the floor when you start the car with the pedal depressed that tells you that the vacuum booster is working.

 

Check the seal between the master and the booster.
If the lines aren't rusty n crusty you can gently maneuver the master out of the way enough to R&R the seal.

Ultimately breaking the lines loose is a better approach. Easier to dig the old seal out.
Now is a good time to bleed the system and replace the rubber lines at the wheel cylinders.
Brake fluid needs to be, should be flushed every 5ish years.