At speeds over 50 mph braking starts pulsating. I replaced the rotors, brakes, calipers. (front and back ). The brakes still pulsate more so when its hot out. What can it be?

 

I would look at the abs system and brake fluid first.

What do you mean by pulsating. Are you getting a code?

 

Did you clean all the corrosion off the hub before you installed the rotor? Corrosion can have the rotor sit out of parallel and cause a vibration.

Did you clean the caliper bracket where the hardware clips in, so the brake pads can slide with little resistance? Did you install new brake hardware clips? A bound brake pad could heat up the rotor and cause warping.

This YouTube channel is really good. He covers a complete front brake job on an accord.