Hard brake pedal while applying brakes

May not be the booster as some do make a noise when the brakes are applied. To test press the brakes several times with engine off, Press the pedal down hard and start the engine , the pedal should move down slightly and there should be no whooshing sound . if the above is ok so is the booster.

sounds maybe booster is diaphram is bad

The most obvious cause for a hard pedal is simply not enough vacuum. check the vacuum. please go to this site for info on hard brake pedal= .mpbrakes.com/techtalk/how-to-series/how-to-diagnosing-a-hard-brake-pedal Goopd-Day!

_______power brake booster, check vacuum to booster and the check valve for brake booster. primary symtom is high hard pedal that requires greater then normal pedal pressure to stop car. testing booster= pump brakes several times with engine off to deplete stored vacuum. turn on engine with pushing slightly on brake pedal. you should be able to feel the pedal fade away a bit, and then become firm. But not hard. if you feel nothing at the pedal when engine starts. Brake booster is not working. Good-day! make sure vacuum is going to booster with engine running. it may just be a bad vacuum line or check valve.

Could be you need a new set of calipers...or changing all of the brake fluid.

That is a Vacuum Problem, You need to Check the vacuum lines @ the Brake Booster, while car is running Listen for Air leak While someone Presses On Brake peddle, Either the Booster is leaking Or 1 of the lines

Power brake booster leaking vacuum.If brake pedal becomes very hard to push then replace brake booster.

Sounds like you brake booster is bad or vac line has become disconnected from booster.

sounds like you have a bad vacuum booster on your brakes or their is a severe systen vacuum leak

Check your front and rear caliper slides for sticking,it sounds like one may be stuck.