Test power brake booster

[Cornpatch MO]

1968 Satellite.. I just converted from manual brakes to power brakes, using original equipment rebuilt replacement parts ( master cyl and booster) correct linkage. How do I test the booster and check valve? And how does the check valve work? My factory service manual does not give this information. I think I may have a bad booster. Brakes work, but has no power assist. Hard pedal. Brakes are adjusted up and are bled ... Master cylinder bled as per directions.. Any info will be appreciated....................MO

 

[69L48Z27]

Quickest thing you can do is rest your foot on the brake pedal and start the car. As soon as the car starts you should feel the pedal fall a little bit.

Pull the check valve out of the booster when the car is running. Engine should change RPM (vacuum leak) and you’ll hear the air sucking in. Stick your thumb over the end and and see if you have vacuum. After the engine is off you can pull the check valve again and see if you hear a rush of air when you pull it, it should be holding vacuum.

 

[twecomm]

If you have a bad / leaky booster, here is a link to a video showing how to test your booster.

If you have a vacuum gauge check how much vacuum you have. Cat remember exactly.. but think you need somewhere around 12 in. minimum for the booster to work properly.