Toro Outcross 9060 Service Manual page 117

Right Turn (continued)
Steering Relief Operation
Outcross 9060
18234SL Rev B
Without load sense flow, pressures on the ends of the steering priority valve
(EC1) start to equalize causing (EC1) to move toward its un-shifted "neutral"
position which directs the fluid needed to turn the machine to the steering valve.
Fluid is routed out manifold port ST, into steering valve port P, through the
steering valve spool, passes through the rotary meter and out the R port to the
steering cylinders. The rotary meter ensures that the fluid flow to the cylinders is
proportional to the amount that the steering wheel is turned. Fluid leaving the
cylinders flows back through steering valve L port, the valve spool, out the T port
and is then returned to the hydraulic reservoir. The steering valve returns to the
neutral position when the steering wheel is released or turning is completed.
When the steering cylinders reach the end of their stroke or if a wheel should
encounter an obstruction (e.g. a curb) while steering, the pressure in the steering
circuit will rise. When steering circuit pressure rises to approximately 20,684 kPa
(3000 psi), relief valve (RV1) in the main manifold opens and allows hydraulic
flow to return to the hydraulic reservoir. This action causes the spool of the
steering priority valve (EC1) to shift and send fluid away from the steering circuit
and to the traction charge and hitch lift circuits. Relief valve (RV1) controls the
action of the steering priority valve (EC1) and allows the valve to divert only
enough fluid flow to the steering circuit to maintain relief pressure.
Page 5–21 Hydraulic System: Hydraulic Flow Diagrams