Disc Brake Calipers

GENERAL

All late 1980 FL and FX motorcycles above VIN 26625-JO have quad (4-sided) seal calipers installed on both the front and rear brake systems of the FL and the rear brake system of the FX models. Instead of the spring retractor system, used on 1978 to early 1980 models, the caliper features a square cross section seal.

To identify front and rear and make the square seal calipers distinguishable from the old style spring retractor units, the front caliper assembly is marked with an additional letter "F" on the piston side subassembly.

1. Rear brake pedal lever

2. Lock nut

3. Master cylinder plunger

4. Clevis

5. Grease fitting

Figure 241B. Adjusting Rear Brake Pedal - FX

The rear caliper assembly is marked with an additional letter "R" on the piston side subassembly.

WARNING

Front and rear calipers are not interchangeable because of a difference in piston retraction. Braking can be affected if calipers are not installed as marked.

The square seal sits in a machined groove in the caliper bore. As the piston is forced out, the seal moves against the chamfer of the caliper groove. When the brake lever is released, the seal springs back, retracting the piston.

Figure 2-42. Late Style Caliper and Piston

DISASSEMBLING DISC BRAKE

CALIPERS - FL FRONT AND REAR, FX REAR

If only the caliper assembly is to be removed, it is not necessary to remove the wheel. To remove the caliper

1.

Bolt (4)

9. Insulator

14.

Bleeder valve

2.

Washer (4)

10. Brake piston assembly

15.

Bushing

3.

Outer caliper half

(1978 to early 1980)

16.

Bushing

4.

Mounting pin

10A. Brake piston (late 1980)

17.

Brake disc

5.

Inner caliper half

10B. Quad seal (late 1980)

18.

Brake disc spacer

6.

Brake pad mounting pins (2)

11. Hydraulic line

19.

Rear brake mounting bracket

7.

Brake pads (2)

12. Piston boot

20.

Rear brake torque arm

8.

Shim

13. O-ring

21.

Bolt, castle nut, washer and cotter pin

Figure 2-43. Disc Brake - Exploded View, FL Front and Rear, FX Rear Only assembly proceed as follows: Remove hose clamp. Remove 4 bolts (1) and washers (2). Remove outer caliper half (3). Remove mounting pin (4) and inner caliper half (5). Remove brake pad mounting pins (6), brake pads (7), shim (8) and insulator (9). Check the pads (7) for wear, damage and looseness. Replace both pads if thickness of friction material is less than 1/16 in. Check to see that the metal backing plate is flat. If it is at all bowed replace the brake pad.

NOTE

Brake pads should only be replaced as a set.

With hydraulic system connected to outer caliper half assembly (3), use a dial indicator to check piston retraction.

Mount dial indicator on back of outer caliper with indicator plunger on the piston face. Apply brake. Set dial indicator on zero. Release brake. Front brake piston stamped "F" should retract 0.020 to 0.025 in. Front brake piston stamped "MF" should retract 0.026 in. to 0.031 In. Rear brake piston stamped "R" should retract 0.033 in. to 0.038 in. If it does not, replace piston assembly (9). Do not remove piston assembly unless there are signs of hydraulic fluid leakage or if piston is not operating properly.

To remove piston (10, 10A), pump brake hand lever until piston will move no farther. Remove hydraulic line (11). Push piston boot (12) back from groove in piston and pull piston the rest of the way out. Remove O-ring (13) on 1978 to early 1980 models. On late 1980 models, remove seal (10A) from caliper..

Remove bleeder valve (14). Clean all parts and Inspect. Replace any parts that are worn, or damaged. Inspect cylinder bore. If it is badly scored replace outer caliper half (3). When reassembling use new O-ring (13).

Inspect the brake disc (17). If it is warped, or badly scored it must be replaced. See "WHEELS" section. If disc is worn excessively, it must be replaced. See "Removing and Installing Brake Disc." Minimum brake disc thickness is stamped on side of disc.

Clean and inspect bushings (15, 16) and pins (4, 6) in fork slider or caliper mounting bracket. Install new bushings and pins if worn or damaged. Coat inside of bushings with Harley-Davidson Anti-Seize before installing caliper.

REASSEMBLING DISC BRAKE CALIPERS — FL FRONT AND REAR, FX REAR (Figure 2-43)

Reassembly is basically the reverse of disassembly. Make sure all parts are clean and in good condition before assembly. Dip all internal parts in DOT 5.

Assemble piston boot to caliper bore. Piston boot has a small hole in it to allow drainage of accumulated moisture. Assemble boot so that hole will point downward when caliper is assembled to motorcycle. Press piston assembly into caliper bore keeping it square to avoid scoring the bore. Push it firmly all the way in.

CAUTION

When installing piston on late 1980 models, make sure seal does not roll or come out of groove in caliper bore.

NOTE

Piston assembly must be pressed all the way into the bore when new brake pads have been installed to assure proper clearance when caliper is reassembled to motorcycle.

When replacing brake pads, sand the surface of the pads with 60 or 80 grit emery cloth on a flat surface to break up the surface glaze. Also, use emery cloth to slightly round off the leading edge of the brake pads. Make sure the shim (8) is positioned between the caliper piston and the outer brake pad so that the direction of wheel rotation is into the "notch."

For best braking efficiency, brake disc on wheel must be parallel with brake pads in caliper assembly. On the rear brake, this is achieved by bending bracket (19), which mounts caliper assembly, until it aligns properly with disc. Insert Alignment Gage, Part No. 97168-77 into holes in bracket (19). Check to see that all three gage pins either touch or are within 1/32 in. of surface of brake disc (17). If one or more pins do not fall within these limits, note which ones and remove gage. Insert Bending Tool, Part No. 97169-77, into bracket holes. Using tool, bend bracket until all three gage pins do either touch or are within 1/32 in. of surface of brake disc (17). A small misalignment of the FL front caliper can be corrected by reaming or changing the bushings (15, 16) in the slider. Severe misalignment may require changing the fork slider.

Install bleeder valve (14). Apply Anti-Seize to 4 bolts (1) before assembly. Assemble caliper unit to fork side. 2-36

Tighten 4 bolts (1) to 35 ft-lbs torque. Coat threads with Harley-Davidson Pipe Sealant with Teflon and connect hydraulic line (11). Assemble hose clamp to front fender or rear fork. Fill master cylinder reservoir with hydraulic brake fluid. Use only D.O.T. 5 hydraulic brake fluid which is approved for use in hydraulic brake systems.

NOTE

Turn handlebar to the left so that top of reservoir is level. Check for leaks. If leaks persist at hydraulic fittings, coat surfaces with Harley-Davidson Pipe Sealant with Teflon. Bleed brake to purge system of air. See "Bleeding Hydraulic System." If after a short period of operation brake feels spongy, repeat bleeding procedure.

DISASSEMBLING DISC BRAKE CALIPER - FX FRONT (Figure 2-44)

Remove the two mounting screws (1) and nuts (2) tc release caliper assembly from front fork. Turn handlebar until top of master cylinder is nearly level. Remove cover and gakset. Disconnect the brake hose hydraulic fitting at brake caliper. Be careful brake hose seat (3) is not lost.

Remove bolt (4) and washer (5) to disassemble caliper halves. Remove seal (6), piston boot (7), piston (8) outer plate (9), brake pad set (10) and inner plate (11) from pins (12). Pull pins from inner caliper (13) for complete disassembly.

INSPECTION AND CLEANING

If brake pads are worn to 1/16 in. or less, replace set (10). Clean all metal parts in a non-flammable cleaning solvent. Blow dry with compressed air. Rubber parts must be cleaned in denatured alcohol or brake fluid.

WARNING

Use a non-flammable cleaning solvent for cleaning metal parts. DO NOT use gasoline or other flammable substances.

Always clean brake system rubber parts by washing in denatured alcohol or brake fluid. DO NOT use mineral base cleaning solvents such as gasoline or paint thinner. Use of mineral base solvents will cause deterioration of the parts and would continue to deteriorate after assembly which could result in component failure.

Inspect all components carefully for excessive wear or damage. Discard old seal (6) and replace with a new one.

Inspect brake discs bolted to wheel assembly and replace ¡1 warped or badly scored. See "WHEELS" for disassembly procedure.

WARNING - The front brake and the rear brake pads must be replaced in pairs only for correct and safe brake operation.

ASSEMBLING DISC BRAKE CALIPER - FX FRONT (Figure 2-44)

Place the two pins (12) in the inner caliper (13). Slide the inner plate (11), brake pad set (10) and outer plate (9) onto the pins.

Dip the seal (6), piston boot (7) and piston (8) into brake fluid before assembly. Use silicone base D.O.T. 5 type fluid. Place the seal, boot and piston into the outer caliper (14).

NOTE

Piston assembly must be pressed all the way into the bore when new brake pads have been installed to assure proper clearance when calipers are reassembled to motorcycle.

When replacing brake pads, place pads on a flat surface and sand the surface of the pads with 60 or 80 grit emery cloth to break up the surface glaze. Also, use emery cloth to slightly round off the leading edge of the brake pads. Make sure the outer plate (9) is positioned between the caliper piston and the outer brake pad so that the direction of wheel rotation is into the "notch."

Position the outer caliper on the pins (12) and secure to inner caliper assembly with washer (5) and bolt (4). Tighten to 45 to 50 ft-lbs torque.

Install bleed fitting (15), if removed, and brake hose seat (3) into outer caliper. Connect brake hose to caliper. Install front wheel, if removed. See "WHEELS."

Mount tne caliper assemDiy 10 me iront tor« wnn two mounting screws (1) and locknuts (2). Tighten screws to 115 to 120 in-lbs torque.

NOTE

New lock nuts should be used as this type of nut tends to lose its holding power when reused. If new lock nuts are not available, Loctite Lock N' Seal (Harley-Davidson Part No. 99625-77) should be used on threads.

Turn handlebar until top of master cylinder is nearly level. Slowly fill reservoir with D.O.T. 5 type hydraulic brake fluid, to gasket level. Reservoir may be filled with pressurized equipment, see "BLEEDING HYDRAULIC SYSTEM."

NOTE

Check for leaks. If leaks persist at hydraulic fittings, coat surfaces with Harley-Davidson "Pipe Sealant with Teflon," Part No. 99630-77. Use only this sealant to avoid contamination of hydraulic system. Bleed brake to purge system of air.

FRONT BRAKE MASTER CYLINDER

DISASSEMBLING FRONT DISC BRAKE MASTER CYLINDER (Figure 2-45)

The master cylinder (1) is located on the right handlebar. Remove from motorcycle as follows: Remove master cyl-

Wheel rotation

Figure 2-44. FX Front Brake Caliper (Left) — Exploded View

1. Mounting screws (2)

3. Brake hose seat

4. Bolt

5. Washer

6. Seal

7. Piston boot

8. Piston

9. Outer plate

10. Brake pad set

11. Inner plate

12. Pins

13. Inner caliper

14. Outer caliper

15. Bleed fitting t

Wheel rotation

Figure 2-44. FX Front Brake Caliper (Left) — Exploded View inder cover (2) and gasket (3) by removing 2 screws (4). Disconnect hydraulic line (5) from master cylinder. Remove handlebar switch assembly and disconnect stoplamp wires. Remove retaining ring (6) and pivot pin (7). Pull out brake lever (8), pin (9), plunger (10), spring (11), 2 washers (12), and dust wiper (13). Remove retaining ring (14) with retaining ring pliers, Harley-Davidson Part No. 96215-49. Pull out piston (15) and O-ring (16) assembly, piston cup (17), spring cup (18), and piston return spring (19).

INSPECTING AND SERVICING (Figure 2-45)

Inspect piston cup (17), and O-ring (16) for wear, softening, and enlarging. Examine cylinder walls for scratches and grooves. Gasket (3) should have no tears, punctures or breaks which would allow leakage. Replace if necessary.

Make sure vent hole in master cylinder cover is open.

ASSEMBLING FRONT DISC BRAKE MASTER CYLINDER (Figure 2-45)

Assemble master cylinder in reverse order of disassembly. If repair kit is installed, use all new parts, not just those that look worn. Dip all internal parts in brake fluid before assembly. Lightly grease pivot pin (7) and pin (9) before assemby. Fill system with DOT 5 hydraulic brake fluid and bleed brake system. See "Bleeding Hydraulic System." Install gasket (3) with flat side down.

IMPORTANT

Before adding DOT 5 hydraulic fluid, check to see that relief port in master cylinder is uncovered when brake lever is released.

NOTE

Hydraulic brake fluid bladder type pressure equipment can be used to fill front brake master cylinder at the bleeder fitting providing master cylinder cover is removed so that system cannot pressurize. Do not use pressure bleeding equipment when the front hydraulic system is sealed with master cyliner cover and gasket in place.

REAR BRAKE MASTER CYLINDER 1978 and Early 1979

DISASSEMBLING (Figure 2-46)

It is not necessary to remove master cylinder from motorcycle to remove piston assembly if replacement is required. Remove rear brake rod clevis pin (1). Pull out plunger (4 or 4A) and remove boot (5), stop wire (6), stop washer (7), piston assembly (8), cup (9), spring (10), valve (12), and valve seat (13).

1.

Master cylinder

11.

Spring

2.

Master cylinder cover

12.

Washer (2)

3.

Gasket

13.

Dust wiper

4.

Screw (2)

14.

Retaining ring

5.

Hydraulic line

15.

Piston

6.

Retaining ring

16.

O-ring

7.

Pivot pin

17.

Piston cup

8.

Brake lever

18.

Spring cup

9.

Pin

19.

Spring

10.

Plunger

Figure 2-45. Front Disc Brake Master Cylinder

2. Cover

3. Gasket

4. Master cylinder

5. Boot

6. Retaining ring

7. Piston

8. Wafer

9. Piston cup

10. Spring seat

11. Spring

12. O-ring

3. Cotter pin 9. Piston cup

4. Master cylinder plunger (FL) 10. Piston return 4A. Master cylinder plunger (FX) spring

5. Cylinder boot 11. Master cylinder

6. Stop wire

3. Cotter pin 9. Piston cup

4. Master cylinder plunger (FL) 10. Piston return 4A. Master cylinder plunger (FX) spring

5. Cylinder boot 11. Master cylinder

6. Stop wire

Figure 2-46. Rear Brake Master Cylinder 1978 and Early 1979 — Exploded View

INSPECTING AND SERVICING (Figure 2-46)

Inspect cup (9) and piston rubber parts for wear, softening and enlarging. Examine cylinder walls for scratches and grooves.

ASSEMBLING (Figure 2-46)

Assemble master cylinder in reverse order of disassembly. If repair kit is installed, use all new parts, not just those that look worn. Dip all internal parts in brake fluid before assembly. Replace fluid and bleed brake system. Adjust rear brake pedal as described under "Adjusting Rear Brake Pedal."

Late 1979 and Later

ASSEMBLING (Figure 2-46)

Assemble master cylinder in reverse order of disassembly. If repair kit is intalled, use all new parts, not just those that look worn. Dip all internal parts in DOT 5 brake fluid before assembly. Fill with DOT 5 fluid and bleed brake system. Adjust rear brake pedal as described under "Adjusting Rear Brake Pedal."

DISASSEMBLING (Figure 2-46A)

Disconnect the brake line at the master cylinder and remove the master cylinder from the motorcycle. Remove the cover screws (1), cover (2) and gasket (3). Drain

Figure 2-46A. Rear Brake Master Cylinder (Late 1979 and Later)

the fluid from the master cylinder (4). Pull off boot (5). Remove retaining ring (6), piston assembly (7), wafer (8) piston cup (9), spring seat (10) and spring (11). Remove the O-ring (12) from the piston (7).

INSPECTION AND SERVICING

Clean parts and inspect piston cup for wear, softening or swelling. Examine cylinder wall and piston for grooves and scratches. Gasket should be replaced if torn or punctured. Replace parts as necessary. When rebuilding master cylinder, replace all of the parts found in the rebuilding kit, not just those that appear to be damaged.

Make sure vent hole in cover is open. ASSEMBLING (Figure 2-46A)

Dip all internal parts in D.O.T. 5 brake fluid before assembly. Assemble master cylinder parts in reverse order of disassembly. Replace the brake fluid and bleed ' the brake system. Adjust the rear brake pedal as described under "ADJUSTING REAR BRAKE PEDAL."

Figure 2-47. Cutaway of Seat Post Springing

SEAT

SOLO SADDLE

SEAT POST SPRINGING

Two seat post spring arrangements are available for this model. A standard spring set is suitable for rider weighing up to 220 pounds. A heavy spring set for weights over that amount include heavier springs and longer guide collars. The heavy set is indicated by a letter "D" stamped on the upper end of the seat post plunger. See figure 2-47 for cutaway view of seat post springing arrangement.

DISASSEMBLING SEAT POST (Figure 2-48)

Remove rod locknut (1) and washer (2) from bottom of frame seat post tube. Pull back of seat upward sharply to break seat post rod nut (5) loose at the base of seat post tube. Unsnap clevis pin spring (3) and pull out clevis pin (4). Tip seat forward and lift out seat post assembly. Disassemble remaining parts in order indicated.

INSPECTING AND SERVICING

Wash and air dry all parts. Inspect for broken or "set" springs. New spring length appears in Figure 2-48 listing. Replace seat bar bushings (18) if worn appreciably.

Figure 2-47. Cutaway of Seat Post Springing

1. Rod locknut

2. Rod locknut washer

3. Clevis pin spring

4. Clevis pin

5. Seat post rod nut

7. Spring adjusting nut

12. Plunger locknut

14. Seat post rod

17. Seat post plunger

18. Seat bar bushings

Figure 2-48. Seat Post — Exploded View

ASSEMBLING SEAT POST (Figure 2-48)

Seat post assembly is reverse of disassembly. Apply liberal coating of "Grease-All" grease to parts, working it into the springs.

For correct spring preloading, draw up spring adjusting nut (8) to compress total visible spring length to 11 in. for standard spring and 10-1/2 in. for "D" heavy springs. Lock with one locknut (6). Turn on other locknut. Posi tion rod nut (5) on rod so bottom end of rod extends through rod nut exactly 3/4 in. Lock adjustment with second locknut.

COMFORT FLEX SEAT

The Comfort Flex seat is adjustable for seat spring firmness and seat spring damping. In addition, a raised position is provided for access to the oil tank and battery located under the seat.

when riding or friction damper (8) will contact the suspension structure. Always place shaft (9) in forward position of slot (10) when lowering seat for riding.

1. Spring adjusting cross rod

2. Spring adjusting slots

3. Seat springs

4. Seat post pin

5. Friction washer

6. Locking ring

7. Castellated nut

8. Friction damper

9. Cross shaft 10. Slot

Figure 2-49. Seat Adjustments

ADJUSTMtNT

Seat Spring Firmness Adjustment (Figure 2-49)

Seat firmness is adjustable to accommodate varying amounts of rider weight by moving upper cross-shaft (1) either forward or rearward into spring adjustments slots (2). Five different slots apply varying amounts of preload to seat springs (3). The front slot provides the greatest firmness - suitable for the heaviest rider/passenger combination. The rear slot provides the least firmness -suitable for the lightest rider without passenger.

Seat Spring Damping Adjustment

Seat spring damping is controlled by friction damper (8) located on left side of seat. The tightness of nut (7) determines the loading on the damper friction washer. Tightening nut (7) increases damping; loosening nut decreases damping. It is recommended that nut (7) be set "finger tight" initially and increased as necessary to prevent any oojecxioriduie spring reuounumg wrien traveling over rougn surfaces. Remove locking ring (6) to make adjustments and replace when finished.

Raising Seat

To place seat in raised position for access to oil tank and battery, remove seat post pin (4), lift seat up toward rear and place lower cross-shaft (9) into upper position of slot (10).

REMOVING AND INSTALLING SEAT ASSEMBLY (Figure 2-50)

Pull out pin (1) from seat post (2). Lift seat up into raised position. Remove two bolts (3), nuts and washers which attach bracket (4) to fender through holes (5). Remove two clamps (6) which attach seat to frame cross tube (7). The seat will now be freed and can be lifted off the motorcycle.

To reinstall seat assembly, reverse the procedure given above for removal while observing for correct clear-

1. Seat post pin

2. Seat post (see insert)

3. Bolt

4. Bracket

5. Fender hole

6. Clamp

7. Cross tube

8. Spacer

9. Nut and washer

10. Rod nut

11. Rod lock nut

12. Adjusting lock nut

13. Tension adjusting nut

14. Screw

15. Backrest

16. Screw

17. Nuts

18. Handrail

19. Seat

20. Speed nut

21. Damper assembly

2. SEAT POST

2-1/16" MAX

1-5/16"

MIN

ri i -

( •

1/2" pi

T U

Figure 2-50. Comfort Flex Seat — Exploded View ances. The seat post height should be 3 ± 1/16 in. from seat post frame to centerline to post pin hole. With upper shaft (1, Figure 2-49) in fifth or rear most slot, the seat should compress fully to its stops and the gas tank clearance must be 1-1/2 in. minimum. There should be adequate clearance between seat and fender, luggage carrier with Tour-Pak, and saddlebags. If seat post height requires adjustment, proceed as follows. Refer to Figure 2-50, remove nut and washer (9) from bottom of seat post and remove seat post from motorcycle. Adjust rod nut (10) to obtain 1/2 in. dimension shown in figure. This dimension should give the seat the correct dimension of 3 ± 1/16 in. Note that adjusting locknut (12) can be removed completely from the assembly and not used at all if necessary to achieve the 3 ± 1/16 in. dimension.

The 1-5/16 in. dimension shown in the figure gives minimum compression on the seat post spring stack which, in turn, allows maximum seat suspension adjustments. The 2-1/16 in. dimension applies some preload to the seat post spring stack which reduces available deflection of springs in seat suspension assembly for heavier riders. These dimensions are determined by adjusting tension adjusting nut (13).

When reinstalling seat post in motorcycle, make sure it is adequately greased.

To establish clearance oetween tne seat assemDiy ana the other parts of the motorcycle, spacers may be required between bracket (4) and fender, and between cross tube (7) and seat base. Minor changes can be made by simply adding shim stock at these two locations.

DISASSEMBLY AND ASSEMBLY

After removal from motorcycle, the seat assembly is partially disassembled by removing items 14 through 20 in the order shown in Figure 2-50. Reassemble in reverse order.

WARNING

When reassembling suspension assembly, position clamps (6) so screws face to the front of the motorcycle and upwards. Improper positioning could cause the clamps to contact the support brackets and break.

MAINTENANCE

Every 2500 miles, lubricate the seat suspension pivol bushings.

Periodically, check mounting bolts and clamps for tight ness.

0 0

Responses

  • ilenia
    What does the vent hole in the lid of a harley front brake master cylinder do?
    6 years ago

Post a comment