FENDER AS-FRONT 3545870 - Caterpillar

Old Style Master Cylinder
(1) High-pressure cup. (2) Retainer. (3) Primary spring. (4) Cup. (5) Secondary piston. (6) Cup. (7) Filler plug. (8) Gaskets. (9) Relief valve. (10) Gasket. (11) Filler plug. (12) Housing. (13) End plug. (14) Seat. (15) Check valve. (16) Spring. (17) Seal. (18) Gaskets. (19) Primary piston. (20) Secondary spring. Disassemble Master Cylinder
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 in a horizontal position.2. Remove filler plugs (7) and (11) from the master cylinder.3. Discard both gaskets (8). These will be replaced with new parts during assembly.4. Insert a wide screwdriver into the body of relief valve (9). Remove the relief valve by turning it counter-clockwise. Remove gasket (10) from inside the reservoir. If relief valve (9) 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 (9) and gasket (10). These will be replaced with new parts during assembly.
End plug (13) is under spring tension. Remove carefully in the following step to prevent injury from flying parts.
6. Remove end plug (13) from the master cylinder. Some internal parts should follow the end plug as it is removed.7. Remove spring (16), check valve (15), and seat (14) from inside the end plug. Discard the spring, check valve, and seat. These will be replaced with new parts during assembly.8. If primary piston (19) did not come out with the end plug, remove by prying away outside gasket (18) with a screwdriver.9. Discard two gaskets (18) and one seal (17). These will be replaced with new parts during assembly.10. Remove secondary spring (20) from inside housing (12).11. Remove the remaining internal parts by pushing secondary piston (5) with a wooden dowel from the push rod end of the master cylinder.12. Remove primary spring (3), retainer (2), and high-pressure cup (1) from end of primary piston (19) or from inside secondary piston (5).13. Discard high-pressure cup (1). This will be replaced with a new part during assembly.14. Remove cup (4) and cup (6) from secondary piston (5). Discard both cups. These will be replaced with new parts during assembly.15. Thoroughly wash all parts to be reused in clean alcohol. Do not use petroleum products to clean master cylinder parts.16. Check the cylinder bore for pitting, scoring, or corrosion. Make sure ports inside housing (12) are open.17. 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.18. Thoroughly wash housing (12) in alcohol after honing, to remove any contamination. Wipe the cylinder bore with a clean, lint-free cloth.Assemble Master Cylinder
Be sure to replace old parts with the new parts contained in the repair kit. Lubricate all rubber components with clean brake fluid before assembly.1.