A dually is a truck that has two rear wheels on each side. These trucks; used to haul heavy trailers or heavy payloads require massive braking power due to their large size. The rear disc brakes must stay in good working condition to stop the rotational mass of those four back tires. If the rotors warp or wear out, you must replace them and the brake pads to ensure your dually will stop when needed.
Open the engine hood, and remove the cover from the master cylinder. Usually, the master cylinder is on the drive's side firewall.
Loosen the lug nuts using the tire iron supplied with the dually on the wheels that you plan to do first..
Place a jack under the rear axle on the driver's side. Jack up the truck until you can place a jack stand under the axle. Lower the truck onto the jack stand. Place wheel blocks in front of the front wheels.
Remove the lug nuts from the wheel studs, and then remove the outer wheel. Pull the spacer off the wheel studs and then pull the inner wheel off the wheel studs.
Remove the two bolts that secure the brake caliper onto the axle housing using a socket and ratchet. Pull the caliper off the brake rotor. If the brake pads do not fall out, remove them from the caliper, and then hang the caliper off the rear shock using a wire tie.
Pry the splined washer off the wheel stud using a slotted screwdriver. Only one wheel stud has a splined washer.
Pull the rotor off the wheel studs, and slide the new rotor onto the wheel studs. Butt the rotor up against the axle hub. Secure it with the splined washer.
Press the caliper piston back into the rear side of the caliper using a pair of pliers.
Place the new brake pads into the caliper. Do not use the old pads. They will wear against your new rotors unevenly and decrease braking efficiency.
Hold the brake pads into the caliper as you slide the caliper over the rotor. Secure the caliper to the axle housing using the bolts, socket and ratchet.
Place the inner wheel, spacer and outer wheel onto the wheel studs. Secure all three in place using the lug nuts. Tighten each lug nut with the tire iron.
Jack up the truck, remove the jack stand, and lower the truck to the ground.
Repeat the process on the other rear brake.
Close the master cylinder cap, and press on the brake pedal until it becomes firm. This seats the brake pads against the new rotors.
