LINES GP-BRAKE 8W4505 - Caterpillar

EJECTOR CHECK VALVE
1. Check valve. 2. Opening to head ends of ejector cylinders. 3. Passage to the opening to the control valve. 4. Piston. 5. Passage. 6. Opening through valve between control valve and rod ends of ejector cylinders.
EJECTOR CHECK VALVE
2. Opening to head ends of ejector cylinders. 6. Opening to rod ends of ejector cylinders. 7. Rod of right side ejector cylinder.When the ejector valve stem is moved to the RETURN position, the pump oil from the control valve goes into passage (3) and opens check valve (1). The pump oil from passage (3) goes through open check valve (1), out through opening (2) into the head ends of the ejector cylinders. The oil in the head ends move the pistons and rods farther out of the ejector cylinders to close the floor. The pistons push the oil out of the rod ends of the ejector cylinders, through passage (6) to the control valve and tank.Relief Valve For Bowl And Ejector Circuits (Early Machines)
The relief valve for the bowl circuit is a part of the control valve for the scraper. The relief valve has both a high and a low oil pressure opening. The high pressure relief setting of approximately 2500 psi (17 200 kPa) is for the pump circuit when the bowl is moved up or when the ejector cylinders open the floor. The high pressure setting can be adjusted by either adding shims (6) for an increase or removing shims for a decrease in the relief pressure setting. The low relief pressure setting of approximately 1300 psi (8945 kPa) is for the pump circuit when the bowl is moved down or when the ejector floor is closed.
SCHEMATIC OF BOWL AND EJECTOR CIRCUIT RELIEF VALVE
1. Piston. 2. Stop. 3. Valve stem. 4. Passage to tank. 5. Passage from common line circuit in control valve. 6. Shims. 7. Spring. 8. Pilot valve. 9. Spring. 10. Opening to tank. 11. Opening to pump circuit. 12. Orifice. 13. Unloading valve.The pump oil is in opening (11), through orifice (12) and through a passage to valve stem (3) when the relief valve feels either the high or the lower oil pressures. For high oil pressure relief the pump oil at valve stem (3) goes through a groove around the valve stem and through a passage to piston (1). The pump oil moves piston (1) against stop (2) which puts more compression on spring (7). The spring now has more force to keep pilot valve (8) closed. If the pressure of the pump oil gets to approximately 2500 psi (17 200 kPa), the pump oil opens pilot valve (8). The oil in the chamber for spring (9) goes through the open pilot valve. Now with only spring (9) force on unloading valve (13), the pump oil in opening (11) moves valve (13) up and the oil goes out through opening (10) to the tank. When pump oil goes through open valve (13), the pump oil pressure does not go higher. When