I just bought a lifted 85 F150 as my first project truck. When I press on the brake it goes right to the floor. I first would like to make sure that the MC has fluid. Where is that located on the 351w engine? If that is full it is probably a leaking line, correct?

 

master cylinder is bolted right to the brake booster. same way on 99.9% of vehicles.you probably blew a line somewhere.

 

Get a Haynes manual - the one for that truck is VERY thorough.