Sticky booster

Hi, have a 66 Caprice with disc kit including double diaphragm booster.

the booster sticks on frequently, requiring the pedal to be lifted. I have checked the pushrod & the pedal is free. I an disconnect the pedal and the booster stays applied, I have to pull it back.

is this a faulty booster?

If you pull the check valve out and release pressure and it still hangs up then yes, it sounds like the booster has an issue.

Thanks Aaron, will check.

Steve