I have a 96 Dodge Ram1500 reg cab V8 318 4X4 auto with a 3in body lift and a 3in suspension lift. The suspension lift is a spacer kit. All steering and suspension parts are stock. When you hit the brakes it pulls hard to the right. The faster you go the harder it pulls. I have replaced all parts that have to deal with the brakes and the tie rods. An I have put a new steering column, steering gearbox, and steering shaft.
You’ve competely changed the dynamics of the suspension in operation, raised the Cg significantly, and I’ll bet you’re running much more rotating mass (huge tires) than original. Rotating mass is like a gyroscope, apply force in one direction and it precesses 90 degrees “out”. The physics is the same whether you’re stopping a truck or playing with a kid’s gyro.
Have you ever notice how huge lifted trucks like yours have shock absorbers mounted sideways (often more than one)? They’re called “steering dampers” and they help compensate for the strange gyroscopic forces at work in monster trucks. Have you installed yours yet?
And by the way, How big ARE your tires?
Wow. You must really love your truck.
When did this braking problem start?
After the body lift, or after the suspension lift?
If the brakes are not the cause then I wonder if you are experiencing a shift in reduced caster on one side due to braking force on the suspension parts. If the vehicle is pulling to the right, it could be less caster on the right that causes pull to the right. This is just a wild guess and I don’t know how you check suspension compliance while braking.