Case MX180, MX200, MX220, MX240, MX270 Tractor Repair Manual

Manuals: Service Manual
General
Engine
Fuel
Electrical
Steering
Power Train
Brakes
Hydraulics
Chassis
Controller Systems
Manual Extract:

When the remote hydraulic control lever is moved to the retract position, the main valve spool is shifted to the right a fixed distance by the proportional solenoid pressure supply. The position of the main valve spool determines the flow rate to the retract port.

As the main valve spool is shifted, flow from the intermediate pressure area is directed to the lower port and to the left hand side of the load check plunger. The plunger is forced to move right unseating the load check pilot poppet. This reliefs the pressure on the spring side of the main poppet back to tank. The plunger contacts and unseats the main poppet which allows the return oil to flow back to the inlet side of the filter base. (Differential pressure between the raise port and the spring side of the main poppet also contribute to unseating the main poppet).

At the same time work pressure is communicated to the signal check through the center drilled passage in the main valve spool. The signal check is forced off the seat and the signal pressure is then directed to the pump compensator to increase PFC pump flow.