IMPLEMENT AND STEERING HYDRAULIC SYSTEM CONTINUED
Steering Control Valve (Steer Left)
When the control valve spool is moved to the STEER LEFT position, the chamber is closed off from the outlet
passage. Signal oil passage is opened to the steer left passage. Even when the priority flow control valve is moved
to the right, some pump oil flows through the metering holes in the priority flow control valve. The flow opens the
load check valve and the pump oil flows around the control valve spool to the steer left passage. The pressure in
the steer left passage increases and oil is sent through the signal oil passage to the chamber. The oil now becomes
signal oil. Some of the signal oil flows through passage #2 to the spring chamber that is behind the priority flow
control valve. The signal oil moves the priority flow control valve to the left. The remaining signal oil pushes the
resolver to the side and the signal oil flows through passage #1 to the inlet manifold. The inlet manifold sends the
signal oil to the compensator valve on the pump. The signal oil causes the pump to upstroke until system pressure
System pressure is approximately 305 psi (2,100 kPa) above the pressure of the signal oil.
As pump oil flow and system pressure increases, the steering oil flow and the pressure through the steer left
passage increases. The increased oil flow through the steer left passage flows through the counterbalance valve to
the steering motor and the machine turns left.
Return oil comes to the steer right passage from the steering motor and from the counterbalance valve. The return
oil flows around the control valve spool and through the outlet passage to the tank.
Figure 24. Steering Control Valve (STEER LEFT).