Harley Davidson brakes are a crucial component for controlling the motorcycle. The caliper is actuated by hydraulic pressure generated by hand pressure applied to the brake lever, which in turn pushes the piston located in the master cylinder. This force is transmitted to the caliper piston, which clamps the brake pads onto the brake rotor, which is fixed to the wheel. This clamp pressure generates friction which converts kinetic energy (rotation) into heat energy, which is then dissipated into the atmosphere by the rotor. Changing the front brakes on a Harley Davidson bike is accomplished with basic mechanic’s tools.
Replacing the Front Brakes
1. Engage the transmission in high gear. Place the lift under the frame close to the front but before the curve of the downtubes. Lift the front wheel clear of the ground. Break the torque on the front axle nut and remove the nut fully. Remove the lower leg cap nuts and cap. Remove the axle from the lower legs and roll the wheel out of the way. Note the position of the wheel spacer and the speedometer drive unit. Inspect the brake rotor for scoring and warping. Replace if either condition is evident.
2. Remove the caliper mounting bolts, then pull the caliper from the lower leg. Suspend the caliper from the triple-clamp with the bungee. Do not support the weight of the caliper with the brake line, as damage may occur to the line. Remove the old pads from the caliper and discard.
3. Collapse the caliper piston with the C-clamp to allow the system to accept the thickness of the new pads. Install the new pads into the caliper. Lightly grease the brake caliper bolts with Moly 44, then reinstall the caliper onto the lower leg. Guide the front wheel back into place. The pads may need to be held lightly in place with finger pressure to allow the rotor to nest into position.
4. Reinstall the front axle, spacer(s) and speedometer drive unit. Ensure that the speedometer drive tab finds the hole in the wheel before torquing the axle, or drive unit damage will occur. Reinstall the lower leg caps and tighten the cap nuts finger-tight. Torque the axle to factory specification for your model of Harley. Torque the cap nuts to factory specification. Spin the front wheel by hand to bench-test the assembly. The wheel should spin freely and have no radial or lateral runout (hop or wobble) and have no visible end-play (side to side). Visible runout or end-play indicate an improperly torqued axle and/or wheel bearing wear, and can cause an unsafe condition for operation.
5. Pump up the front brakes with the brake lever and ensure that the feel at the lever is normal (not spongy) and that it does arrest wheel rotation. Lower the lift and place the transmission in neutral. Push the bike by hand and actuate the brake lever. The brakes should immediately grab and stop the bike. Check the fluid level in the master cylinder and top off if needed.