I changed the front rotors and brake pads once i was done i started the truck and the brake pedal went to he floor and the dash ifo said to service brakes. since than the brakes have been hard and sometimes pulsate if i have to stop quick what is the problem with them and how do i solve this

It went to the floor because you had to compressed the piston to get it over the new pads and rotors. The brakes need to be pumped up after you replace pads in order for the pistons to come back in contact with the new pads and take up the gap. Pushing the pedal to the floor is never a good idea and a good way to ruin a master cylinder in older vehicles.

As far as the pulsation, have the rotors turned. Make sure the wheels are torqued to the proper spec when you are done (140 lb/ft). Pump up the pedal when you are done and you should have smooth braking.

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