Harley rear brake pads and discs need to be inspected at every service interval or whenever the components are removed during regular service or repair procedures. Replace both rear brake pads if the friction material of either pad is .016″ (4mm) or less. Brake pads must always be replaced as sets. Minimum acceptable thickness of the rear brake disc is stamped on the side of the disc. If your rear disc is .180″ or less it will need to be replaced. The disc will also need to be replaced if it is warped or excessively scored from heat.
To replace Harley rear brake pads, it is important to start with the motorcycle standing upright on a level surface. Remove the right side saddle bag and release the rear wheel speed sensor cable from the retainer on the rear brake hose. The Brembo calipers are assembled and secured with metric hardware. Brake pads are not removed until the caliper is removed but it is helpful to loosen the brake pad retaining pin while the caliper is held secure to the caliper bracket. Remove the pin clip, then use a 5mm allen to loosen the pin.
It is important to remove the master cylinder top cover before continuing. Remove the two caliper retaining bolts with an 8mm allen then tip the caliper to slightly retract the pistons and lift the caliper off of the bracket and disc. Now the Harley rear brake pad pin can be removed. Use a large (#3) flat blade screwdriver to push against the old brake pads and retract the caliper pistons. Then, remove and discard the old brake pads.
Correctly place the new brake pads into the caliper and secure with the retaining pin. Slide the caliper over the disc and tighten the mounting hardware 43 to 48 foot pounds. Now torque the pin 75 to 102 inch pounds and install the clip. Pump up the rear brake pedal and set the correct brake fluid level before installing the reservoir top cap.