69 camaro brakes

[wisemanz28]

Lately I noticed my brake pedal is really hard when using the brakes, also sometimes I here a groaning noise when pushing on the pedal. The car stalled a few times when stopping. I haven't checked anything out yet but wanted to get some tips on what I should be looking for. 

[bertfam]

Booster or a leak in the vacuum system going to the booster.

Ed

[ZLP955]

What Ed said.
Let the engine idle for a minute or two, depress brake pedal, then switch engine off keeping foot pressure on the brake; if pedal doesn't hold position, there's a leak in the manifold, hose, check valve or internally in the booster.

[wisemanz28]

I started the car up today and at idle I revved it up and when I gained rpm,s the brake pedal depressed down , when I let it go back to idle the pedal raised up and got very hard again. Checked the vacuum hose and check valve and they looked good . Any way to check the brake booster?

[ZLP955]

Definitely sounds like the booster. Pump the brake pedal 5 or 6 times with the engine off, to deplete vacuum. Then push down on the brake pedal with moderate pressure, and start the engine; if the pedal drops (1/4"-1/2") that suggests the booster is functioning correctly.

[wisemanz28]

I suspect the brake booster is the problem, who would you guys suggest I send it to for a rebuild ?

[69Z28-RS]

https://www.brakeboosters.com/