Front Master Cylinder

Removal/Installation (1972-1981)

Refer to Figure 29 for this procedure. 1. Attach a hose to the front caliper bleed valve (Figure 30). Then open the bleed valve with a wrench and drain the brake fluid by operating the hand lever. Discard the brake fluid.

CAUTION Brake fluid will damage paint and chrome part. Wipe up any spilled fluid

immediately, then wash the area with soap and water.

2. Loosen the front brake hose (5, Figure 29) at the front of the caliper.

3. Disconnect the brake light switch wires at the master cylinder.

4. Remove the master cylinder mounting bolts and remove the master cylinder (1, Figure 29).

5. Installation is the reverse of these steps. Note the following.

6. Install the master cylinder mounting bolts. Tighten the bolts securely.

7. Connect the stop light switch wire connector at the master cylinder (if so equipped).

8. Connect the brake and reservoir supply hoses at the master cylinder.

WARNING Harley-Davidson specifies DOT 3 brake fluid for models produced prior

FRONT MASTER CYLINDER (1972-1981 FL; 1973-1981 FX)

1. Master cylinder

2. Cover

3. Gasket

4. Screw

5. Hose and fitting

6. Retaining ring

7. Pivot pin

8. Brake lever

10. Plunger

11. Spring

12. Washer

13. Dust wiper

14. Circlip

15. Piston

16. O-ring

17. Piston cup

18. Spring cup

19. Return spring to September, 1976 and DOT 5 for later models. Mixing the two types of brake fluids can cause brake failure. If you own a 1976 or 1977 model take your frame number to a Harley-Davidson dealer to find out your bike's production date.

9. Fill the master cylinder with new brake fluid. Bleed brake system as described under Bleeding the System in this chapter.

10. Install the master cylinder gasket and cover after bleeding the brakes.

WARNING Do not ride the motorcycle until you are sure the brakes are working properly.

Overhaul (1972-1981)

Refer to Figure 29 for this procedure.

1. Remove the master cylinder cover (2, Figure 29) and gasket (3). Pour and discard any remaining brake fluid.

2. Remove the pivot pin retaining ring (6) and pull the pivot pin (7) out of the caliper. Remove the brake lever.

3. Remove the following parts in order:

4. Remove the circlip (14). Then remove the piston (15), piston cup (17), spring cup (18) and piston return spring (19).

5. Discard the piston O-ring (16).

6. Carefully inspect the piston cup, spring cup and piston return spring. Replace these parts if required.

7. Inspect the master cylinder walls for scratches or wear grooves. The master cylinder housing should be replaced if the cylinder walls are damaged.

8. Check to see that the vent hole in the cover is not plugged.

9. Coat all internal parts with specified brake fluid before assembly.

10. Install a new O-ring (16) on the piston.

11. Referring to Figure 29, assemble the piston assembly in the following order:

a. Piston return spring (19).

12. Referring to Figure 29, install the plunger assembly as follows:

13. Lightly grease the pivot pin (7). Then install the hand lever and pivot pin (7). Secure the pivot pin with a new circlip (6).

Removal/Installation (1982-on)

Refer to Figure 31 for this procedure.

1. Attach a hose to the front caliper bleed valve (Figure 30). Then open the bleed valve with a wrench and drain the brake fluid by operating the hand lever. Close the bleed valve and discard the brake fluid.

CAUTION Brake fluid will damage paint and chrome parts. Wipe up any spilled fluid immediately, then wash the area with soap and water.

2. Remove the union bolt (5, Figure 31) and disconnect the brake line (7) at the front of the caliper. Remove the 2 washers (6).

3. Remove the master cylinder-to handlebar clamp bolts (13) and remove the master cylinder (1).

4. Installation is the reverse of these steps.

5. Fill the master cylinder with new specified brake fluid. Bleed brake system as described in this chapter.

Overhaul

Refer to Figure 31 for this procedure.

1. Remove the master cylinder cover (2) and gasket (3).

2. Remove the hand lever pivot pin circlip (8) and remove the pivot pin (9) and hand lever (10).

3. Remove the reaction pin (23) from the hand lever.

4. Referring to Figure 31, remove the following in order:

a. Pushrod and switch actuator (22).

WARNING All 1984 FL and FX models do not use the backup disc (18, Figure 31) because of a design change with the master cylinder piston. Use of the backup disc on these models may cause brake drag or brake lockup. See your Harley-David-son dealer.

5. If damaged, remove the grommet and sight glass from the rear side of the master cylinder housing.

6. Carefully inspect the O-ring, cup, dust boot and grommet for softening or wear. Replace these parts if required.

7. Inspect the master cylinder walls for scratches or wear grooves. The master cylinder housing should be replaced if the cylinder walls are damaged.

8. Check to see that the vent hole in the cover is not plugged.

31) FRONT MASTER CYLINDER

Master Cylinder Parts
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