General
The rear brake master cylinder is mounted to the right side rider footrest/rear brake pedal bracket.
If the rear brake feels spongy or excessive pedal travel exists or the brake does not work at all, proceed with Inspection which follows.
Caution! Direct contact of DOT 4 brake fluid with eyes can cause irritation. Avoid eye contact. In case of eye contact flush with large amounts of water and get medical attention. Swallowing large amounts of DOT 4 brake fluid can cause digestive discomfort. If swallowed, obtain medical attention. Use in well ventilated area. KEEP OUT OF REACH OF CHILDREN.
Notice: DOT 4 brake fluid will damage painted and body panel surfaces it comes in contact with. Always use caution and protect surfaces from spills whenever brake work is performed. Failure to comply can result in cosmetic damage.
Note. If DOT 4 brake fluid contacts painted surfaces, IMMEDIATELY flush area with clear water.
Inspection
1. Check the level of fluid in the rear brake reservoir. If it is low, refill and bleed brake system. See 2.17 BLEEDING BRAKES.
2. Check for fluid leaks in the brake line, around banjo fittings or rear brake caliper piston or bleeder valve. Repair and bleed brake system.
- a. For brake line replacement procedure, see 2.16 BRAKE LINES.
- b. To repair rear brake caliper, see procedure in 2.15 REAR BRAKE CALIPER: XR 1200X.
- c. See 2.17 BLEEDING BRAKES for hydraulic brake system bleeding procedure.
3. Check rear brake friction pads and disc for excessive wear or damage. Replace as necessary.
- a. See 1.17 BRAKE PADS AND DISCS: XR 1200X for specifications.
- b. See 1.17 BRAKE PADS AND DISCS: XR 1200X, Brake Pad Replacement: Rear for brake pad replacement procedure.
- c. See 2.5 WHEELS for brake disc replacement procedure.
4. Eliminate any air in the hydraulic brake assembly by bleeding the system. See 2.17 BLEEDING BRAKES.
If none of these conditions exist but the rear brake system does not operate properly, repair or replace as necessary.
Removal
Caution! Direct contact of DOT 4 brake fluid with eyes can cause irritation. Avoid eye contact. In case of eye contact flush with large amounts of water and get medical attention. Swallowing large amounts of DOT 4 brake fluid can cause digestive discomfort. If swallowed, obtain medical attention. Use in well ventilated area. KEEP OUT OF REACH OF CHILDREN.
1. See Figure 2-91. Drain rear brake master cylinder reservoir (7) and remove feed hose (8) from master cylinder feed hose port fitting. Discard hose clamp. See 2.13 REAR BRAKE MASTER CYLINDER RESERVOIR.
Figure 2-91. Rear brake master cylinder and reservoir: 1. Retaining ring; 2. Clevis pin; 3. Yoke; 4. Screw and washer (2); 5. Washer (2); 6. Banjo bolt; 7. Reservoir; 8. Feed hose; 9. Fastener (2)
2. Install end of a length of 5/16 in (7.9 mm) ID clear plastic tubing over rear caliper bleeder valve and place free end of tubing in a suitable container.
3. Open bleeder valve about 1/2-turn. Pump brake pedal to drain brake fluid. Close bleeder valve but do not tighten.
Note. Dispose of brake fluid in accordance with local regulations.
Warning! Wear safety glasses or goggles when removing or installing retaining rings. Retaining rings can slip from the pliers and could be propelled with enough force to cause serious eye injury.
4. Remove retaining ring (1) from clevis pin (2). Remove clevis pin and disengage master cylinder yoke (3) from brake pedal. Discard retaining ring.
Note. Damaged banjo bolt surfaces will leak when reassembled. Prevent damage to seating surfaces by carefully removing brake line components.
5. Remove banjo bolt (6) and washers (5). Lift banjo fitting away from master cylinder. Discard washers.
6. Remove two screws (4) securing rear master cylinder to master cylinder mounting bracket and remove rear master cylinder.
7. If it is necessary to remove master cylinder/footpeg mounting bracket, remove fasteners (9). See 2.42 RIDER FOOT CONTROLS: XR 1200X.
Disassembly
Notes:
- Do not disassemble the rear master cylinder unless problems are being experienced. Discard all seals during the disassembly procedure. Install a complete rebuild kit when the unit is reassembled.
- Clamp rear brake master cylinder in a vise by its mounting bosses only. Use brass or aluminum jaw covers or other protective device on vise jaws to prevent damage to master cylinder.
1. See Figure 2-92. Clamp rear brake master cylinder in a vise with yoke pointing up.
Figure 2-92. Holding yoke: 1. Incorrect; 2. Correct
Note. Grip yoke by the edges with an adjustable wrench. Do not grip yoke by the flats or the yoke may become deformed.
2. Hold yoke with an adjustable wrench. Using an open-end wrench, loosen shoulder nut. Remove yoke.
3. See Figure 2-93. Remove nut (4) from pushrod (5).
Figure 2-93. Rear brake master cylinder: 1. Retaining ring; 2. Clevis pin; 3. Yoke; 4. Nut; 5. Pushrod; 6. Boot; 7. Retaining ring; 8. Piston; 9. Primary cup; 10. Piston spring; 11. Retaining clip; 12. Dust cover; 13. Pushrod retainer; 14. O-ring; 15. Feed port fitting
4. Remove and discard boot (6).
Warning! Wear safety glasses or goggles when removing or installing retaining rings. Retaining rings can slip from the pliers and could be propelled with enough force to cause serious eye injury.
Notes:
- Do not remove boot collar nut from pushrod.
- Use correct retaining ring pliers and correct tips. Verify that tips are not excessively worn or damaged.
5. Thread nut (4) back onto pushrod several turns, to protect pushrod threads.
6. Press down on pushrod to compress piston spring (10). Remove retaining ring (7), pushrod (5) with boot collar nut, piston (8) with secondary cup, primary cup (9) and piston spring (10). Discard retaining ring, piston/cup assembly and piston spring.
7. Remove dust cover (12), retaining ring (13), feed port fitting (15) and O-ring (14). Discard retaining ring and O-ring.
Cleaning, inspection and repair
Warning! Use denatured alcohol to clean brake system components. Do not use mineral-based solvents (such as gasoline or paint thinner), which will deteriorate rubber parts even after assembly. Deterioration of these components can cause brake failure, which could result in death or serious injury.
Warning! Compressed air can pierce the skin and flying debris from compressed air could cause serious eye injury. Wear safety glasses when working with compressed air. Never use your hand to check for air leaks or to determine air flow rates.
1. Thoroughly clean master cylinder body and all brake system components. Blow out drilled passages and piston bore with low pressure compressed air from a clean air supply. Do not use a wire or similar instrument to clean drilled passages.
2. Carefully inspect all parts for wear or damage and replace as necessary.
- a. Inspect piston bore in master cylinder housing for scratches, grooves, scoring, pitting or corrosion. Replace housing if any of these conditions are found.
- b. Inspect outlet port that mates with brake line banjo fitting. This is a critical sealing surface. If necessary, replace housing.
3. Verify that vent holes in master cylinder are completely open and free of dirt or debris.
Assembly
| FASTENER | TORQUE VALUE | |
| Brake master cylinder, rear, pushrod nut: XR 1200X | 130-173 in·lbs | 14.7-19.6 Nm |
Notes:
- When assembling rear brake master cylinder, always use new parts from the service parts kit. Consult the PARTS CATALOG for the correct kit part number.
- CCI #20 BRAKE GREASE is recommended for lubrication of cylinder bore, cups and seals prior to assembly.
- Stand master cylinder on wooden block or clean, lint-free towel to protect seating surfaces.
Warning! Wear safety glasses or goggles when removing or installing retaining rings. Retaining rings can slip from the pliers and could be propelled with enough force to cause serious eye injury.
Note. Use correct retaining ring pliers and correct tips. Verify that tips are not excessively worn or damaged.
1. See Figure 2-93. Coat new O-ring (14) with DOT 4 BRAKE FLUID. Install O-ring and feed port fitting (15) into feed port on master cylinder body. Secure with new retaining ring (13). Verify that retaining ring is fully seated in groove.
2. Slide dust cover (12) onto feed port fitting and press into place in master cylinder feed port.
Note. Clamp rear brake master cylinder body in a vise by its mounting bosses only. Use brass jaw covers or other protective device on vise jaws to prevent damage to master cylinder.
3. Clamp master cylinder in a vise with banjo fitting end pointing down.
4. See Figure 2-94. Lubricate master cylinder bore, new piston (1) with new secondary cup (3), and new primary cup (2) with CCI #20 BRAKE GREASE supplied in the service parts kit.
Figure 2-94. Rear master cylinder piston, pushrod and spring assembly: 1. Piston; 2. Primary cup; 3. Secondary cup; 4. Piston spring; 5. Pushrod; 6. Boot collar nut; 7. Pushrod retainer; 8. Piston spring mounting boss
Warning! Wear safety glasses or goggles when removing or installing spring. Spring tension can cause spring, attached components and/or hand tools to fly out which could result in death or serious injury.
5. Press small end of new piston spring (4) onto mounting boss (8) on piston.
6. Slide piston/spring assembly, flared end of spring first, into cylinder bore so that spring seats against counter bore (recess) at bottom of cylinder.
7. Apply approximately 0.1 g of G40M BRAKE GREASE to ball end of pushrod.
Warning! Wear safety glasses or goggles when removing or installing retaining rings. Retaining rings can slip from the pliers and could be propelled with enough force to cause serious eye injury.
Note. Use correct retaining ring pliers and correct tips. Verify that tips are not excessively worn or damaged.
8. See Figure 2-93. Temporarily thread nut (4) onto pushrod (5) several turns to protect pushrod threads.
Figure 2-95. Adjusting pushrod length: 1. Clevis pin hole; 2. Mounting boss hole; 3. Adjustment distance
9. Insert pushrod into master cylinder body. Press down on pushrod to compress piston spring (10). Slide pushrod retainer down into master cylinder bore and hold in place.
10. Secure pushrod assembly with new retaining ring (7). Verify that retaining ring is fully seated in groove. Remove nut (4) from pushrod.
11. Apply approximately 0.1 g of G40M BRAKE GREASE around groove in boot collar nut. Carefully slide boot (6) down onto pushrod and into end of master cylinder bore. Press lip of boot down around groove in boot collar nut.
12. Thread nut (4) onto pushrod (5), several turns past flats.
13. Thread yoke (3) onto pushrod, at least 2-3 turns past flats.
14. See Figure 2-95. Measure distance (3) from centerline of clevis pin hole (1) in yoke to centerline of master cylinder mounting boss hole (2) closest to yoke. This distance must be 2.64-2.76 in (67.1-70.1 mm). Adjust yoke until this distance is obtained.
Note. Grip yoke by the edges with adjustable wrench. do not grip yoke by the flats or the yoke may become deformed.
15. While holding yoke with an adjustable wrench, turn shoulder nut back against yoke. Tighten to 130-173 in·lbs (14.7-19.6 Nm).
16. Remove master cylinder assembly from vise.
Installation
| FASTENER | TORQUE VALUE | |
| Brake master cylinder, rear, mounting screw: XR 1200X | 72-96 in·lbs | 8.1-10.9 Nm |
| Brake line banjo bolt | 20-25 ft·lbs | 27.1-33.9 Nm |
Warning! Wear safety glasses or goggles when removing or installing retaining rings. Retaining rings can slip from the pliers and could be propelled with enough force to cause serious eye injury.
1. See Figure 2-91. Assemble and install master cyl-inder/footpeg mounting bracket if it was removed. See 2.42 RIDER FOOT CONTROLS: XR 1200X.
2. Install rear master cylinder assembly to mounting bracket with screws and washers (4). Tighten to 72-96 in·lbs (8.110.9 Nm).
3. Fit yoke (3) onto foot pedal. Install clevis pin (2). Secure with new retaining ring (1).
Note. Master cylinder housing has a positive stop for banjo fitting. When tightening banjo bolt into master cylinder in the next step, rotate banjo fitting clockwise until it contacts positive stop.
4. Position a new washer (5) on each side of hydraulic brake line banjo fitting. Insert banjo bolt (6) through washers and fitting. Thread banjo bolt into master cylinder housing. Tighten to 20-25 ft·lbs (27.1-33.9 Nm).
5. Install rear brake master cylinder feed hose (8) on master cylinder feed hose port fitting. Secure with new hose clamp.
Caution! Direct contact of DOT 4 brake fluid with eyes can cause irritation. Avoid eye contact. In case of eye contact flush with large amounts of water and get medical attention. Swallowing large amounts of DOT 4 brake fluid can cause digestive discomfort. If swallowed, obtain medical attention. Use in well ventilated area. KEEP OUT OF REACH OF CHILDREN.
Notice: DOT 4 brake fluid will damage painted and body panel surfaces it comes in contact with. Always use caution and protect surfaces from spills whenever brake work is performed. Failure to comply can result in cosmetic damage.
Notes:
- If DOT 4 brake fluid contacts painted surfaces, IMMEDIATELY flush area with clear water.
- Rear brake master cylinder reservoir must be in a level position when filling and checking fluid level.
- Reservoir cover may be removed from rear brake master cylinder reservoir to more easily verify fluid level in reservoir.
- Use only DOT 4 BRAKE FLUID from a sealed container.
- Do not overfill reservoir. Do not reuse old brake fluid.
6. Position motorcycle upright (not resting on jiffy stand).
7. See Figure 2-96. Remove reservoir cap (2).
Figure 2-96. Rear brake master cylinder reservoir: XR 1200X: 1. Reservoir; 2. Reservoir cap; 3. Upper fluid level; 4. Lower fluid level
8. Fill rear master cylinder reservoir (1) with DOT 4 BRAKE FLUID until the fluid level reaches the UPPER mark (3) on the reservoir.
9. Bleed brake system. See 2.17 BLEEDING BRAKES.
10. Turn ignition switch ON. Test operation of stop lamp.
Warning! After servicing brakes and before moving motorcycle, pump brakes to build brake system pressure. Insufficient pressure can adversely affect brake performance, which could result in death or serious injury.
Warning! After repairing the brake system, test brakes at low speed. If brakes are not operating properly, testing at high speeds can cause loss of control, which could result in death or serious injury.
11. Test ride motorcycle at low speed. If brake feels spongy, repeat bleeding procedure.