Harley-Davidson recommends brake pads always be replaced in sets.
The brakes on a Harley-Davidson motorcycle do not require much in the way of overall maintenance, except for periodic inspection of the pads for wear to determine when they need to be replaced. Pad replacement intervals will depend on several factors, including the type of riding and how hard the brakes are used. When changing Harley-Davidson brake pads, for safety the pads for both the front and rear brakes should be replaced at the same time.
1. Remove the reservoir cap on the rear master cylinder to allow for fluid expansion and internal pressure to escape when the calipers are retracted.
2. Loosen the small retaining bolts (pad-pins) that attach the brake pads with the socket wrench. Slide the blade of the putty knife between the pad and caliper. Push the caliper back into the bore by applying steady pressure with the flat of the knife.
3. Pull the pin-pads until the inside pad comes free. Do not remove the pin-pads from the caliper shoe yet; you will need to use them to align the new pad.
4. Install the new inside pad in the same orientation, with the curved side facing to the back of the bike. (On Softail models the curve needs to face upward.) Insert the pin-pads until you hear a distinct “click.” Do not fully tighten.
5. Push the outside brake pad’s caliper back into the bore with the flat of the putty knife. Check that the inside pad is firmly in place and now completely remove the pad-pins, freeing the outside pad. Install the new pad and replace the pad-pins, tightening them with the torque wrench to between 180 and 200 inch-lbs.
6. Loosen, but do not remove, the pad-pins with the socket wrench. Remove the caliper mounting bolts and pull the caliper assembly free from the fork.
7. Push the caliper back into the bore by applying steady pressure with the flat side of the putty knife. Remove the pad-pins and pads from the caliper assembly.
8. Install the new pads in the same orientation. Insert the pad-pins until you hear them click into place. Do not tighten. Reattach the caliper assembly to the fork. Hand-tighten the top (long) mounting bolt and then the bottom (short). Tighten the bottom mounting bolt first, then the top, to between 28 and 38 ft-lbs with the torque wrench. Tighten the pad-pins to between 180 and 200 inch-lbs.
9. Start the bike, pump the brakes until the pads contact the disc. Check the fluid level and replace the reservoir cap. Test drive the bike. Bleed the system if the brakes feel spongy.