brakes wont stop

my 87 b2000 wont stop when i hit the brakes. it will slowly roll to a stop at higher speeds and its really unsafe. so far ive done a master cylinder, 2 new calipers up front and new pads. been powerbled correctly,no air in the lines. the last thing i can think of is the brake booster. does this sound like a brake booster? when its off, i can pump up the pedal and it is firm but it doesnt hold any pressure. any help needed, thanks. i need to get it good to drive 20 miles to trade it. thanks

Make sure your fluid is toped off, make sure you still have an operating one way valve in the hose from the booster to the intake manifold.

Look here for a good overall brake testing and pieces parts guide.

lol im not good with that diagram. could you dumb it down a little bit for me?

Just scroll down to the "testing" procedures, page 49. The other stuff was for educational purposes.

Those testing procedures can't get any easier and apply to any vehicle. Dan

1. I'd adjust the rear brake shoes manually first. That doesn't cost anything.

2. A power brake booster needs to hold vacuum, can be tested.

3. You could remove the vacuum hose to the power brake booster and plug the line, see if that makes things worse when you (carefully) drive.

4. You could jack up the truck and have Mrs. 87.2wd.b2000 step on the brakes, and you go around and spin the wheels by hand to see if one or more is not being "held" by the brake system. This is a whole lot safer if the engine is off for this test.