When rear brake pads on a Harley-Davidson Road King fall below 0.04 inch (1.02mm) in thickness, it is time to replace them. Triggers that you might need to check the wear on your brakes include excessive noise while braking, increased difficulty in braking or the brake pedal is having to travel further while braking. The two rear brake pads are located within the brake caliper mounted on the rear wheel.
Open the right saddle bag and twist the two quick-release studs 1/4 turn clockwise. Place it out of the way.
Place a small drain pan or shop rag under the rear brake master cylinder. Remove the master cylinder cover using a cross-tip screwdriver.
Loosen but do not remove the pad pins on the rear brake caliper using a 1/4 inch 12-point socket.
Insert a putty knife between the inner pad and the caliper to force the caliper piston to retract. Pull the pad pins out part of the way to allow the inside brake pad to drop free. Observe the pad as it drops free in order to reassemble in a like manner.
Install the new inner brake pad with the curved portion facing the rear of the motorcycle. Slightly tighten the pad pins and pump the rear brake sufficiently to seat the inner pad.
Slide a putty knife between the outer pad and the piston. Apply pressure to the pistons to cause them to retract. Loosen and completely remove the pad pins to allow the outer pad to drop. Install the new outer pad and completely tighten the pad pins. Torque the pins to 6 to 8 inch-pounds (0.7 to 0.9 Nm) using a torque wrench.
Pump the rear brake pedal several times to move the new brake pads into contact with the rotor. Check the rear brake master cylinder fluid level and add D.O.T. 5 silicone brake fluid, if necessary. Replace the master cylinder cover and tighten the screws.
Reinstall the right saddlebag.
Always install the rear brake pads as a set. Never replace just one pad--doing so can result in instability and a failure of the brake system.