I am in the final stages of my engine compartment resto. of my 70ss. I replaced the brake booster with a Delco and reused my master cylinder. The master cylinder works fine. I bled the brakes several times to get all the air out of the lines. The brake pedal goes down with little resistance and then the brake light comes on. The front rotors are hard to turn. Could this be a booster push rod adjustment issue? Any help would be appreciated. Thanks!