Remove Brake Master Cylinder
1. Disconnect the master cylinder linkage (1) from the brake pedal.
2. Thoroughly clean around the hydraulic hose connections and cylinder ports, mark the hoses for identification, then disconnect the hoses (2). Cap or plug all openings.
3. Remove the mounting bolts (3).
4. Move the master cylinder (4) out of the mainframe.
5. Loosen the linkage jam nut (5), mark the distance the linkage is installed in the master cylinder, then remove the linkage from the master cylinder.
Install Brake Master Cylinder
1. Install the linkage (1) into the master cylinder to the mark made when removing the linkage. Tighten the jam nut (5).
2. Fill the master cylinder (4) with clean hydraulic oil and plug all openings.
3. Move the cylinder into position in the mainframe and install the mounting bolts (3).
4. Pin the master cylinder linkage to the brake lever.
5. Thoroughly clean around the hydraulic hose ends and master cylinder ports, then connect the hoses (2) to the cylinder.
6. Bleed the master cylinder. For procedures, see Vehicle System, Systems Operation, Testing and Adjusting, Form No. KEBR 1240.
Disassemble Brake Master Cylinder
Pressure regulating spring assembly has been set at the factory and should never be disassembled, readjusted or interchanged with another valve.
1. Remove the boot (1) and the pressure regulating spring assembly (2).
2. Separate end cap (21) from housing.
Separation of end cap from housing will release tension in spring (19). The spring could fly unexpectedly from housing and cause personal injury. Use care when removing end cap from housing.
3. Remove gasket (14).
4. Remove primary cup (17), retainer, spring (18), and residual valve (20) from end cap.
5. Remove cap screw (13) from under side of housing (11). Remove O-ring (12) from cap screw.
6. Remove retaining ring (8) from housing.
7. Remove sleeve (10) by pulling on push rod. Remove cup (9) from sleeve.
8. Remove piston (16) from housing. Remove piston ring (15) from piston.
9. Carefully remove retaining ring (3) with a small flat tool. Do not scratch bore of sleeve (10).
10. Remove push rod (4), spool (6), and spring (7) from sleeve. Remove cup (5) from spool.
Assemble Brake Master Cylinder
If spool, sleeve, or bore of housing is damaged, scratched or broken, the entire assembly must be replaced. These parts are select fitted and are not interchangeable or replaceable with service items.
1. Clean and inspect all component parts for scratches, cracks or wear. Replace any parts that are excessively worn or damaged.
2. Install new cup (9) on sleeve (10) and new cup (5) on spool (6).
NOTE: Lips on cups should be away from ends of spool and sleeve.
3. Place spring (7) in sleeve.
4. Install spool (6) in sleeve (10).
5. Install push rod (4) in sleeve and secure it with new retaining ring (3).
6. Install new O-ring (12) on cap screw (13) and install in housing (11).
7. Carefully install sleeve (10) into housing.
Make sure that groove on sleeve will engage cap screw.
8. Install retaining ring (8).
9. Install new piston ring (15) on piston (16) and install in housing.
10. Place new residual valve (20), spring (19), and retainer (18) in end cap (21).
Residual valve must be checked for proper seating in end cap.
11. Place new gasket (14) on mounting face of end cap and new primary cup (17) on end of spring (19).
12. Assemble end cap with its components to housing making sure lip on primary cup has properly engaged bore of housing.
13. Install lock washers and bolts. Tighten to 21.8 to 24.5 Nm (16 to 18 ft lb).
14. Install pressure regulating spring assembly (2) on push rod. Install new boot (1).