First check if it is the brakes, block the drive wheels up, drive in forward and reverse for the prescribed 10 or 15 minutes, make sure you are engageing the brakes frequently, when the wheels show signs of slowing or stopping. put in neutral and turn the wheels by hand ,if they are locked up check and see if you have proper "free pedal" (the clearance between the actuator rod and the master cylinder piston)you should be able to wiggle the rod slightly. you may need to shorten the stroke to ensure proper clearance so the brakes fully release when the pedal is in the home (non applied) position