If you feel pedal vibration, check the following items:

Worn or damaged brake pads

If your brake pads are worn or damaged, this can cause the pedal to vibrate. 

Replace brake pads if necessary.

Worn or damaged brake disc

Inspect the brake discs. 

If they are worn or damaged, this can cause brakes to grab suddenly and have uneven braking. 

You will need to replace the brake discs. 

Always replace them in pairs.

Bend or damaged hub or bearing

Inspect the hubs and bearings. 

If they are damaged or bent, this will cause the vehicle to vibrate through the pedal and steering system. 

Replace hubs and or bearings if necessary.

Pedal mounting, bushes and bearings

Inspect the pedal system, mountings, bushes and bearings. 

If any of these have been damaged or worn they need to be replaced.