Normally in a vehicle with vacuum boost brakes, you can stomp the brake pedal and feel a firmer pedal because the brake booster has not caught up. Slow pressure on the pedal will allow the booster to pull the pedal with vac assist and the pedal will be easier to push. A hard pedal, locking up brakes, with little pedal force is not something I have dealt with. That is unless you have hydroboost and the correct brake pedal.