Usage:
New Style Master Cylinder
(1) Retaining ring. (2) Primary piston. (3) High-pressure cup. (4) Retainer. (5) Primary spring. (6) Cup. (7) Secondary piston. (8) Cup. (9) Filler plug. (10) Gaskets. (11) Relief valve. (12) Gasket. (13) Filler plug. (14) Housing. (15) End plug. (16) Seat. (17) Check valve. (18) Spring. (19) Seal. (20) Retainer. (21) O-ring. (22) Seat. (23) Retainer. (24) Secondary spring.
Disassemble Master Cylinder
NOTE: Before starting disassembly, obtain the repair kit for the master cylinder. The part number for the repair kit is located in the Parts Book for the machine.
1. Place the master cylinder in a vise with end plug (15) facing up.
2. Remove filler plugs (9) and (13) from the master cylinder.
3. Discard both gaskets (10). These will be replaced with new parts during assembly.
4. Insert a wide screwdriver into the body of relief valve (11). Remove the relief valve by turning it counter-clockwise. Remove gasket (12) from inside the reservoir.
NOTE: If relief valve (11) seems stuck, position screwdriver on the relief valve and rap sharply with a hammer. This should loosen the relief valve for removal.
5. Discard relief valve (11) and gasket (12). These will be replaced with new parts during assembly.
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End plug (15) is under spring tension. Remove carefully in the following step to prevent injury from flying parts. |
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6. Remove end plug (15) from the master cylinder. Retainer (20) should follow the end plug as it is removed.
7. Remove spring (18), check valve (17), and seat (16) from inside the end plug. Discard the spring, check valve, and seat. These will be replaced with new parts during assembly.
8. Remove retainer (23), seat (22), seal (19), and o-ring (21) from retainer (20). Discard these four pieces. They will be replaced with new parts during assembly.
NOTE: O-ring (21) may stay inside housing (14) when retainer (20) is removed. Remove and discard o-ring (21).
9. Remove secondary spring (24) from inside housing (14).
10. Remove the remaining internal parts by pushing primary piston (2) with a wooden dowel from the push rod end of the master cylinder.
11. Remove cup (6) and cup (8) from secondary piston (7). Discard both cups. These will be replaced with new parts during assembly.
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Primary piston (2) is under spring tension. Remove carefully in the following steps to prevent injury from flying parts. |
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12. Press primary piston (2) into secondary piston (7). Remove retaining ring (1) from inside secondary piston (7). Discard the retaining ring. This will be replaced with a new part during assembly.
13. Separate primary piston (2) from secondary piston (7).
14. Remove primary spring (5), retainer (4), and high-pressure cup (3) from end of primary piston (2) or from inside secondary piston (7).
15. Discard high-pressure cup (3). This will be replaced with a new part during assembly.
16. Thoroughly wash all parts to be reused in clean alcohol. Do not use petroleum products to clean master cylinder parts.
17. Check the cylinder bore for pitting, scoring, or corrosion. Make sure ports inside housing (14) are open.
18. If necessary, hone the cylinder bore lightly. Use brake fluid as a lubricant while honing. If the bore does not clean up readily, the entire master cylinder must be replaced with a new part.
19. Thoroughly wash housing (14) in alcohol after honing, to remove any contamination. Wipe the cylinder bore with a clean, lint-free cloth.
Assemble Master Cylinder
NOTE: Be sure to replace old parts with the new parts contained in the repair kit.
NOTE: Lubricate all rubber components with clean brake fluid before assembly.
1. Install primary spring (5), large end first, into secondary piston (7).
2. Set retainer (4) into the small end of primary spring (5). Note the correct direction of the retainer.
3. Install a new high-pressure cup (3) onto the end of primary piston (2). Note correct position of cup (3).
4. Insert cup (3) end of primary piston (2) into secondary piston (7). The end of primary piston (2) must fit inside retainer (4).
5. Press primary piston (2) into secondary piston (7). Install a new retaining ring (1) inside the secondary piston.
6. Install new cups (6) and (8) onto secondary piston (7). Note correct position of the two cups.
7. Insert the piston assembly inside housing (14).
8. Install secondary spring (24), small end first, over the piston assembly inside housing (14).
9. Install a new seat (22) into a new retainer (23). Install this assembly into retainer (20).
10. Install a new o-ring (21) into housing (14).
11. Install a new seal (19) on retainer (20). Set retainer (20) in place inside housing (14). Make sure o-ring (21) is not pinched or twisted.
12. Install a new seat (16), new check valve (17), and new spring (18) inside end plug (15).
13. Thread end plug (15) assembly into housing (14). Tighten the end plug to 68 to 108 N·m (50 to 80 lb. ft.).
14. Set a new gasket (12) inside the reservoir at the relief valve opening.
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Do not turn the adjusting screw on relief valve (11). This would change the relief setting, and could prevent the master cylinder from operating correctly. |
15. Thread a new relief valve (11) into place inside the reservoir. Use the slots in the relief valve body to tighten the relief valve to 20 to 27 N·m (15 to 20 lb. ft.).
16. Install two new gaskets (10) on top of the reservoir. Thread filler plugs (9) and (13) into place.