Truck has a death bounce when brakes are applied

4x4hippie

I just bought this 1999 Chevy Silverado 1500LS 4X4 5.3L 150,000 in january. Since I first drove it it has a violent bounce when I apply the brakes. First thing I did was changed front rotors and pads thiking warped rotor up front. Still there. Checked ball joints and wheel bearing, all good. Just replaced the idler arm and assembly bracket. Problem still there. Just bought new rotors and pads for back waiting to install. If this doesn't cure this death bounce, I'm lost. Only happens during braking! The suspension all they way around the truck is good. No leaking shocks, all bushings, tie rod ends and all are good. If these new rotors and pads don't happen to cure it, where should I look next? Calipers?

Mr_Shiftright

How's the alignment? Caster could be way off.