Rotor and drums are out of round, need turned, probley just the rotors.
Be sure to replace the pads and shoes too.
You said it is bouncing. If the body is bouncing then the shocks are bad and need replacing.
probably brake rotors and pads.
I am sorry there needs to be more info.on this....are you saying when you have the flashers on and apply the brakes that the hazard lights go out??
If the truck feels like it is slowly bouncing while stopped at a light, it needs suspension repair badly.
ABS means either Antilock Braking System or Anti-Blockier System, depending on where you live. (What it does: if you stomp really hard on the brakes, it will rapidly apply and release the brakes for you, keeping you from skidding out of control and crashing.) If the ABS light is on in your Ford truck, that means the electronics that control the anti-lock part of your brakes are not working, and you need to take the truck to a mechanic.
1. you need to check your brake fluid. If it is TOO low, then no brake fluid to help stop the vehicle. 2. You need to get new brakes.
I had the same issue on my Sierra 1500 and it ended up being the rotors, take your truck to a brakes specialist or any other place you take your vehicle for a brake inspection and its most likely your rotors are warped meaning bent out of shape.
apply your brakes gently while accelerating at the same time
Most common cause of that is the rotors are out of round are warped. REPLACE ROTORS.
IF THIS ONLY HAPPENS WHEN YOU APPLY THE BRAKES THE MOST LIKELY PROBLEM IS THAT YOUR FRONT BRAKE ROTORS ARE WARPED. YOU CAN EITHER HAVE THEM MACHINED AT A QUALITY AUTOMOTIVE SHOP OR REPLACE THEM WITH NEW ROTORS.
Brakes will be dependent upon what type of truck you have and what you are doing with your truck. There is a website that can help brakeworld.com will help walk you through the right selection of high performance brakes for your truck.
Quick Service brakes and parking brakes.
This varies based on the model of truck. First determine if your truck has drum brakes or disc brakes. See related questions and links for more specific details on replacing brakes for specific models of Ford trucks.