Brake Drum

 WARNING: DO NOT INHALE DUST FROM BRAKES OR ASSOCIATED COMPONENTS. INHALATION OF DUST CAN BE HAZARDOUS TO YOUR HEALTH. COMPRESSED AIR OR BRUSHES MUST NOT BE USED TO CLEAN BRAKES, BRAKE DRUMS (1126) OR ASSOCIATED COMPONENTS. A VACUUM CLEANER (ROTUNDA BRAKE/CLUTCH/SERVICE VACUUM 164-R3600 OR EQUIVALENT) EQUIPPED FOR THIS PURPOSE SHOULD BE CAREFULLY USED TO REMOVE ANY DUST. ADHERENT DUST SHOULD BE REMOVED WITH A DAMP RAG. ANY DUST SHOULD BE CONTAINED IN A SEALED AND LABELED BAG FOR DISPOSAL. WEAR AN APPROVED HIGH EFFICIENCY CARTRIDGE OR AIR LINE RESPIRATOR AND USE EXTRA CAUTION TO AVOID BREATHING THIS DUST.

NOTE: Before servicing the rear brakes, refer to Section 06-05, Removal and Installation, Control, Parking Brake procedures.

Removal

1. Raise the vehicle so the tire and wheel (1007) are clear of the floor and install safety stands under the axle.

2. Remove the hub cap (if equipped), tire and wheel.

3.  CAUTION: Use of a drum puller or a torch is not recommended. Drum distortion may result.

   Remove the spring retaining nuts and remove the brake drum.

4. If the brake drum is rusted to the axle shaft pilot diameter, use coarse sandpaper to remove the rust buildup, then remove the brake drum.

   If the brake drum will not come off, insert a narrow screwdriver through the brake adjusting hole in the brake backing plate (2211), and disengage the brake shoe adjusting lever (2A176) from the brake adjuster screw (2041). While holding the brake shoe adjusting lever away from the brake adjuster screw, loosen the brake adjuster screw with the Brake Adjustment Tool D81L-1103-C or equivalent. Loosen the brake adjuster screw only if the brake drum cannot be removed. Do not burr, chip, or damage the notches in the brake adjuster screw or the self-adjusting mechanism will not function properly.

   If the brake adjuster screw was loosened, check to be sure the brake shoe adjusting lever is still properly seated in the shoe web.

   Retracting Brake Shoes, Rear, F-250, F-350

   

5. Check the surface of the brake drum. If worn, or if brake drum is suspected of having excessive runout, the brake drum should be machined. After machining, check maximum diameter of the brake drum. Brake drum must be replaced if diameter is outside maximum limit. Maximum drum diameter is stamped on the outside of the brake drum.

Installation

1. Remove the protective coating from a new brake drum with Metal Brake Parts Cleaner F3AZ-19579-SA or equivalent.

2. Adjust the brakes as described in this section.

3. Install the brake drum onto the axle shaft flange or rear hub (1109).

4. Install the retaining clips securely. Install the wheel on rear hub studs against the brake drum, and tighten the retaining nuts to specification listed in the Wheel Torque Specifications chart at the end of this section.