16. BRAKE SYSTEM MXU550EXi/MXU500i Dust Boot Press the piston and turn the brake shaft counterclockwise to expand boot, then the brake shaft does not touch piston. Piston Parking Brake Arm Spring Install the parking brake arm and spring. Align the parking brake arm with the brake fluid inlet hole as shown. Brake Fluid Inlet hole Adjusting Bolt Install the adjusting bolt and lock nut. Do not turn in the adjusting too much and do not tighten the lock nut. Lock Nut 16-45