I replaced both brake pads and rotors on both the front and rear of my 2007 Jeep Liberty but when I brake, especially from a higher spped such as an exit ramp, there is shaking/pulsating in the brake pedal. What could be the source of this shaking?

Bleed brakes starting with rt rear then lft rear then right front then left front. Make sure you have a large can of brake fluid and watch fluid closely and add fluid as required

Sounds like you need brakes or there is a rock stuck in between the caliper and backing plate.

Seel Immediate repairs before you loose your brakes alltogether.

Hi Wayne, I'm glad to help!

You'll need to support the vehicle on safety stands. Then take off the front wheels, Then take off the calipers that hold your brake pads. Then take off the bracket that the caliper is bolted too. Then remove the rotor. I suggest replacing the pads as well and be sure to clean the rust from where the pads rest on and make sure they slide easy back and forth, this will help in a longer life for the pads. Hope this helps and have an awesome day Wayne.

most likly warped rotors, they need to machined or replaced, and new brake pads as well

you have the handbrake inside the the rear brake disk its all in one with the disk

I had the same experience in the past and it turned out to be the caliper that was getting stuck and the pads would not retract away from the rotors causing friction and eventually burning your pads.

one thing you didn't mention is if the dealer replaced the caliper hardware. take alook at this:
http://www.aa1car.com/library/tr996.htm

take your pads back off take the backing plate off load a bunch of anti sqeek between the pad and plate then the plate and caliper should solve your problem unless its your coposition off your pads some grades of semi metallic pads just sqeek.

Was the Rotors turned on the last front brake Service?....Sounds like uneven rotors in front

You must have a piston stuck in one caliper, and it's not releasing the pressure off your brake pad.