Hard brake pedal

This sounds like a failed brake booster. A quick test is to have the engine off and pump the brakes a few times, do not remove your foot from the pedal, start the engine and the pedal should suck down a little if not the booster is faulty or you have a supply vacuum problem. There is a large hose attached to the booster near the master cylinder, this is the vacuum supply. Run the engine and remove this hose, as you remove it you should hear the vacuum and the engine will probably stall, this is normal. If this is the case, check the check valve at the booster is serviceable (air will flow one way and not the other) and if that is okay, the booster is probably faulty.