Hard brake pedel

[72beatuptruck]

i bought old beat 72 chevy recently. the truck has factory tilt and ac. other than that the truck is pretty worn out. the original 350 was taken out and a 292 6 was put in. the question i have is the truck has vacuum but the brake pedel is hard as a rock to push down. i have drove it like this but its kinda scary. what could be the problem? i have changed the check valve and that did nothing. what else could it be?

[LONGHAIR]

It sounds like the diaphragm is shot.
If you can get someone to help you, try this.
Disconnect the vacuum line from the booster and plug it with your finger. Have the helper start the engine. Slightly move your finger off of the end of the line, to be sure it has vacuum, but block it quickly so the engine doesn't die. If it does indeed have vacuum, tell the helper to press on the brake. Now quickly plug the vacuum line back into the booster. The helper should feel the difference. If there is no difference, the booster is your problem.

BTW welcome from another Ohio member.

[El Jay]

Welcome aboard.
Longhair pretty much covered it all.

[72beatuptruck]

A welcome and an edit in the same thread....

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