KIT-MASTER CYLINDER 8R4071 - Caterpillar

Illustration 1 g00484634
(1) Opening from the control valve (2) Orifice in the check valve (3) Check valve (4) Opening to the rod end of the cylinder (5) Opening to the head of the cylinder (6) Spring chamber (7) Passage from the control valve (8) Check valve that ventsThe check valve is located on the bowl cylinder. The carry-check valve will keep the bowl in any position. In order for the carry-check valve to work, the valve spool for the bowl must be in the HOLD position. The HOLD position of the bowl valve spool stops the oil in the vent line to check valve (8) . Then, check valve (8) can not open. When check valve (8) is closed, the oil from the rod end of the cylinder in opening (4) can not open check valve (3) .Only when the bowl valve spool is in the LOWER position, check valve (8) is open to the tank. The pump oil from the control valve in passage (7) flows through opening (5) into the head end of the cylinder. The oil in the head end moves the piston and rod, which lowers the bowl. The piston moves the oil from the rod end of the cylinder through opening (4) . The oil pressure from the rod end of the cylinder on the surface of check valve (3) opens the valve. When check valve (3) is open, the oil in spring chamber (6) flows through check valve (8) and into the vent line that is open to the tank. The oil from the rod end flows through the open check valve, through opening (1) to the control valve and to the tank.When the bowl valve spool is moved to the RAISE position, the pump oil from the control valve flows through opening (1) and opens check valve (3) . The check valve opens because the pump oil has more pressure than the pressure of the oil and the spring in spring chamber (6) and the rod end of the cylinder. The oil in spring chamber (6) flows through orifice (2) when check valve (3) is opened by the pump oil.The pump oil flows through the check valve through opening (4) into the rod end of the cylinder. The pump oil moves the piston and rod, which raises the bowl. The piston moves the oil out of the head end of the cylinder through opening (5) into passage (7) to the control valve and tank.