severe Nose driving while braking. *brakes*

[bnoon]

Nose dive has nothing to do with the brakes themselves. Either the front or rear shocks are shot, your front springs are weak, or both. You said the truck sat for 15 years and shock valves can go bad from sitting just like any other seal, no matter what the outside looks like, and the springs sag on these trucks pretty bad too after all of these years. You should be able to put the biggest baddest brakes on the planet on that truck and nose dive will still have nothing to do with the brakes themselves.