I have changed the front brakes to new vl turbo rotors that are cross drilled and slotted and my brake peddle still shudders when i am braking. Could the problem be in the back brakes or rotors?

more than likely. unless you didnt adjust the wheel bearings propely and they loose. if its in ya pedal it can be rears but if its in the sheering wheel it will be fronts

its just the pedal

well check the backs. are the rotors ****ed, do they have a lip on them, can u see hotspots, are they undersize

best way is just get the back brakes machined will be a gem once done

Sounds like warped rotors to me.. Get them machined, new pads would be beneficial at the same time.

yeh i had same prob on mine ages ago discs were warped bad as felt and the vibrating got worse when i braked going fast ull either need to get em machined or buy new discs

get your discs machined. i had that problem in my first vlct. not an expensive job

i put new rotors on a while back and they shuddered after a while. put all new front end bushes in after that (not tooo fix it) but it did. radius rods, control arms etc. a tight front end will help tolerate and play in discs