ENGINE AR-PRIM 4752473 - Caterpillar

Sudden movement of the machine or the release of oil under pressure can cause personal injury. At operating temperature, the hydraulic oil is hot and under pressure. Hot oil can cause burns. To prevent possible personal injury, release the pressure in all of the implement circuits before any hydraulic lines or components are disconnected or removed.
1. Release the pressure in the hydraulic system as follows:a. Move the machine to a smooth horizontal location. Move away from working machines and personnel.b. Permit only one operator on the machine. Keep all other personnel either away from the machine or in view of the operator.c. Move the switch for the CUSHION-HITCH to the "LOCKDOWN" position. Be sure the rear bracket assembly of the hitch is down against (resting on) the front hitch assembly.d. Activate the parking and secondary brakes. Lower the bowl to the ground. Lower the apron. Stop the engine.e. Move all scraper control levers to all positions to release the pressure in the hydraulic system.f. Carefully loosen the fill cap on the hydraulic oil tank to release the pressure in the tank.g. Be sure all hydraulic pressure is released before any fittings, hoses or components are loosened, tightened, removed or adjusted. Wait at least five minutes after the machine is turned off. 2. Remove four bolts (1), the washers and bypass valve (2) from the hydraulic oil tank. Remove the O-ring seal from the bypass valve filter cover. 3. Remove the screen assembly and two filter elements (3) from the hydraulic oil tank. 4. Disassemble bypass valve (2) as follows:a. Remove three pop rivets (14) and the bypass housing assembly from the filter cover assembly.
Retainer (5) has spring force behind it. When pin (10) is removed, the spring force will be released. The spring will extend approximately 143.76 mm (5.660 in). To prevent possible personal injury, retain the spring with retainer (5) while pin (10) is being removed.
b. Hold retainer (5) down, and remove pin (10) from the shaft. Slowly release the retainer. Remove two retainers (5), spring (13), valve plate (17) and shaft (16) from bypass housing (15).
Retainer assembly (12) has spring force behind it. When bolt (7) is removed, the spring force will be released. The spring will extend approximately 219.7 mm (8.65 in). To prevent possible personal injury, retain the spring with retainer assembly (12) while bolt (7) is slowly being removed.
c. Hold retainer assembly (12) down, and slowly loosen bolt (7). Slowly release the retainer assembly. Remove bolt (7), washer (8) and spacer (9).d. Remove retainer assembly (12) and spring (11) from filter cover (6).e. If necessary, remove drain plug (4) from the filter cover. The following steps are for the installation of the hydraulic oil filters and bypass valve.5. Be sure all parts of bypass valve (2) are thoroughly clean prior to assembly. Check the condition of the O-ring seal used in filter cover (6) and on drain plug (4). If the seals are damaged, use new parts for replacement.6. Assemble bypass valve (2)