hey all i recently developed a brake issue with my 79 bronco. i replaced the pads shoes and drum and rotors and the wheel cylinders, and last nite i replaced the master cylinder which kinda helped but the problem still exists. the problem is the peddal goes all the way to the floor and the wheels would nomally lock up but it won't and i need much more distance to stop. i am thinking of getting the brakes bleed soon, and then check out the vacuum source cause when the brakes are applied the engine seems to almost chug out and stall and when the bronco is stopped or the brake is released the engine returns back to normal. when the truck is cold and i start it and go to the end of the block it stops on a dime but once it warms up the brakes seem to go away even though i can still stop but need more distance to stop so i have not been driving the bronco. so with this being said i am thinking the vacuum source or as some other people suggested the vacuum check valve is faulty. not sure what that check valve is or where to find it.does anyone know of a diagram of the engine vacuum for the brakes. i have searched the haynes manuals and the internet but nothing. any ideas?