PISTON 2912695 - Caterpillar

Illustration 1 g00340180
Steering Neutralizer Valve in the OPEN Position (1) Stop assembly. (2) Inlet port. (3) Outlet port. (4) Tank port. (5) Spring. (6) Stem.
Illustration 2 g00386778
Location of the Left Neutralizer Valve (1) Stop assembly. (7) Left neutralizer valve.The steering neutralizer valves prevent the engine end frame from contacting the non-engine end frame during a turn. The steering neutralizer valves block the flow of pilot oil to the steering control valve. This causes the machine to stop articulating at the end of a complete turn.The machine is equipped with two steering neutralizer valves, a right valve and a left valve. The two steering neutralizer valves are identical. Additionally, there is a right stop assembly and a left stop assembly. The stop assemblies are mounted to the non-engine end frame.Pilot oil flows from the steering pilot valve to either the right neutralizer valve or to the left neutralizer valve through inlet port (2). The pilot oil then flows around stem (6) to outlet port (3). Spring (5) holds stem (6) to the left in the OPEN position. The pilot oil then flows through the check valves for the steering neutralizer valves. The pilot oil then flows to the steering control valve.When the machine is turned to the far right, the right stop assembly contacts stem (6) of the right neutralizer valve. This should only occur when the machine is turned to the full RIGHT TURN position. This will cause spring (5) to be compressed by stem (6) .As stem (6) moves to the right, the stem blocks the flow of pilot oil through port (2). Because pilot oil cannot flow from port (2) to port (3), no pilot oil can flow to the steering control valve.When the flow of pilot oil stops acting on the spool in the steering control valve, the steering control valve spool returns to the NO STEER position. This causes the steering action to stop.Before steering action can begin, the STIC steering control lever must be moved to the left. This allows pilot oil to flow from the return end of the steering control valve spool to port (3) of the right neutralizer valve. The oil then flows past stem (6) to port (4). Then, the oil flows to the hydraulic oil tank for the steering and brake systems. This allows the steering control valve spool to move to the LEFT TURN position, and the machine begins to turn to the left.As the machine turns to the left, right stop assembly (1) will move away from stem (6). The force of spring (5) acts against stem (6). This causes the stem to move left. As the stem moves left by a small amount, the stem opens port (2). This allows return pilot oil to flow from port (3) through port (2) to the steering pilot valve.The left neutralizer valve operates in the same manner as the right neutralizer valve.