SLEEVE 3349644 - Caterpillar

This control valve section is between the valve section for lift control and the outlet manifold or between the valve section for lift control and the valve section for the ripper. This section is for bulldozer tilt control. The operation instructions that follow are for a bulldozer tilt control valve.The bulldozer tilt control valve controls the tilt of the bulldozer blade. The control valve is equipped with these components: valve spool (1), line relief valve (2) and load check valve (11) .The bulldozer tilt control valve is spring centered. Valve spool (1) is controlled by a mechanical linkage that is connected to the bulldozer control lever. When valve spool (1) is in the HOLD position the oil from the pump in passages (9) and (13) flows around valve spool (1) and into passage (12). The pump oil in passage (12) flows to the outlet manifold of the control valve or to the next section. The pump oil in passage (10) does not go to the tank because passage (10) does not have an outlet. The HOLD position of valve spool (1) and check valve (11) blocks the oil in passage (7), passage (14), and passage (8). The piston and the rod in the cylinder cannot move until the control lever and the valve spool are moved away from the HOLD position.Load Check Valve
Load check valve (11) prevents reverse oil flow in the bulldozer tilt cylinder, which can cause cylinder drift or load loss. The load check valve does not open until pump oil pressure in passage (10) overcomes the force of the spring for the load check valve and of the cylinder oil pressure in passage (8) .Line Relief Valve
Illustration 2 g01305479
Line Relief Valve (2A) in the HOLD position.Line Relief Valve (2B) with the relief valve in the ACTIVE position.Line Relief Valve (2C) with the makeup valve in the ACTIVE position. (6) Passage to the tank (14) Passage to the rod end of the cylinder (16) Adjustment screw (17) Nut (18) Spring (19) Plunger (20) Ball (21) Chamber (22) Spring (23) Spool (24) Valve (25) Inlet passage (26) Drain passage (27) PassageThere is a line relief valve (2) in the line of the rod end of the tilt cylinder. The valve has two purposes. As a relief valve, the valve limits the maximum amount of pressure in the cylinder line, when the valve spool is in HOLD position. As a makeup valve, the valve permits oil from the return line to add with implement oil.Relief Valve Operation
Cylinder oil flows into passage (25) of line relief valve (2). The oil then flows through passage (27) that is between spool (23) and valve (24). The oil then fills chamber (21) for spring (22). The pressure of the oil and the force of spring (22) keep valve (24) closed when the oil pressure is less than the setting of the relief valve.When the pressure of the oil in passage (14) that is acting on the right end of valve (24)