Throughout the years, Harley-Davidson motorcycles were equipped with either a drum or hydraulic disc front brake system. The older drum-style setup used a steel cable to pull a set of brake shoes against the brake drum. Over time, brake shoe wear and the cable's natural tendency to stretch would result in a loose brake lever, requiring the lever to be pulled in almost to the hand grip to slow the motorcycle. Likewise, disc brakes are affected by air and condensation buildup within the hydraulic system. While drum brakes could be adjusted by tightening the cable, hydraulic brakes must be bled to remove trapped air or contaminants.
Instructions
Front Drum Brake Adjustment
1. Lift the motorcycle's front wheel off the ground, using a service stand.
2. Spin the front wheel by hand and pull the front brake lever. Ideally, the front brake should engage as the lever passes through a quarter of its full range of motion.
3. Pull the rubber sleeve away from the front brake cable adjuster, located behind the left fork leg near the steering pivot. Loosen the adjuster lock, using a combination wrench. Turn the adjuster clockwise to tighten the brake cable, moving the brake lever's engagement point away from the hand grip, or turn the adjuster counterclockwise to loosen the cable and move the engagement point closer to the hand grip. Adjust the cable, as needed, until the brake engages one-quarter of the way into the brake lever's range of motion when pulled in.
4. Spin the front wheel again, this time without pulling in the brake lever. The wheel should spin freely without dragging on the front brake shoes. If the front brake drags or prevents the wheel from spinning easily, loosen the brake cable slightly and spin the wheel again. Pull the rubber sleeve over the brake cable adjuster if the wheel can spin freely.
5. Loosen the brake shoe pivot stud, located on the left side of the front wheel's brake drum, as well as the front axle nut, using a socket wrench. Do not remove the stud or the axle nut.
6. Spin the wheel again and pull the front brake lever in as far as possible. Hold the brake lever in place and tighten the brake shoe pivot stud firmly against the brake drum. Tighten the front axle nut to 50 foot-pounds, using a torque wrench. Release the front brake lever.
7. Spin the wheel again. Pull the front brake lever in and take note of how far the brake lever travels before engaging the brake. Adjust the brake lever, using the brake cable adjuster, as needed.
8. Remove the service stand and lower the motorcycle onto its side stand.
Front Disc Brake Air Bleeding
9. Park the motorcycle on its side stand. Turn the handlebars to the right until the front brake master cylinder fluid reservoir, located on the right handlebar, is in a level position. Cover the fuel tank and the center of the handlebars with a heavy cloth towel.
10. Remove the cap and the inner diaphragm from the fluid reservoir, using a Phillips screwdriver. Transfer the old brake fluid held in the reservoir into a plastic container, using a siphon or syringe. Pour in fresh brake fluid until the reservoir is 3/4 full.
11. Place a box-end wrench over the front brake caliper bleed screw, located either at the rear or along the top of the caliper. Push a three-foot length of clear plastic tubing over the end of the bleed screw and the wrench. Place the opposite end of the tubing in your plastic container.
12. Pull the rubber boot off the brake hose fitting at the rear of the front brake master cylinder, if equipped. Place a box-end wrench over the fitting, then tightly wrap a shop towel around the fitting and the wrench. Pull in the brake lever, then loosen the fitting a half-turn. A small amount of air and brake fluid will seep out from the loosened fitting. Tighten the fitting, then slowly release the brake lever. Repeat four more times to completely remove air from the front master cylinder. Carefully unwrap the shop towel and remove the box-end wrench. Tighten the fitting to 15 foot-pounds, using a torque wrench.
13. Refill the fluid reservoir until the reservoir is 3/4 full.
14. Loosen the brake caliper bleed screw a quarter-turn, then pull the brake lever in slowly to push a small amount of brake fluid into the clear tubing Tighten the bleed screw and slowly release the brake lever. Repeat until the fluid trapped in the tubing is light amber in color and no longer has air bubbles or debris suspended within it. Tighten the bleed screw to 80 inch-pounds.
15. Refill the fluid reservoir until the the brake fluid level is flush with the raised step cast into the rear of the reservoir, or is 13/64-inch, or 5 mm, below the top of the reservoir. Reinstall the inner diaphragm and lid onto the fluid reservoir.
16. Pump the front brake lever repeatedly. You should feel an increasing amount of resistance as the brake lever moves a quarter of the way through its range of travel. Rebleed the front brake if you do not feel resistance, indicating that air is still trapped within the brake circuit.
17.Wipe up any spilled brake fluid, using a shop towel. Turn the handlebar to the left.
Tags: brake lever, front brake, brake fluid, bleed screw, brake cable, fluid reservoir