FLANGE 4597719 - Caterpillar

A shuttle valve (resolver) is a check valve. The shuttle valve compares two pressures. The lower pressure of the two pressures is blocked. The higher pressure (signal) flows to the next component in the resolver network.
Illustration 1 g00511526
Typical control valve (1) Shuttle valve (resolver)There is one shuttle valve (resolver) per implement control valve. The shuttle valve of one control valve compares the work port pressure to the work port pressure of an upstream control valve. The highest resolved signal pressure from the two control valves is sent to the next shuttle valve in the signal resolver network.The shuttle valve (resolver) can be affected by certain adverse conditions: debris, cut seals, missing seals, bad ball seats and missing balls.Troubleshooting for the Resolver Network
The signal network can be easily tested. Start the engine and warm up the hydraulic oil. Cycle all the implements several times in order to ensure that warm hydraulic oil circulates through the entire hydraulic circuit.Operate the engine at low idle for the test. Connect a 30000 kPa (4000 psi) gauge to the signal line pressure tap. Operate each control lever in the following order:
Ripper lever (RAISE position)
Lift lever (RAISE position)
Tilt lever (TILT RIGHT position)Watch the gauge. Maximum system pressure should be seen for each circuit. Use the gauge in order to detect small leakage problems such as cut seals or missing seals.If debris is detected in the system, remove all the balls from the shuttle valves (resolver) and flush the system by operating the implements. Enough flow is supplied in order to flush the debris to the tank.Malfunctioning valves may be caused by other factors: incorrect linkage adjustment, a broken spring in the pressure reducing valve, a flow control spool out of position and a failed main relief valve.Pump Efficiency Test
Hydraulic oil pressure can remain in the hydraulic system on this machine after the engine and pump have been stopped. Serious injury can result if this pressure is not released before any service is done on the hydraulic systems. In order to prevent possible injury, release the hydraulic system pressure before working on any fitting, hose, or hydraulic component.Lower all attachments to the ground before service is started. If the hydraulic system must be serviced, tested, or adjusted with the attachment in the raised position, the attachments and lift cylinders must be supported properly.Always move the machine to a location away from the travel of other machines. Be sure that other personnel are not near the machine when the engine is running and tests or adjustments are being made.
This test determines whether a pump is operating within design parameters. Presently, only a bench test is available. The test should only be run if all the cycle times are too slow and the resolver network is in proper working order.Pump efficiency is the pump flow at 6900 kPa (1000 psi) over the pump flow at 690 kPa (100 psi). Pump flow is measured in L/min (US gpm) at the same rpm.The difference between the pump flow of two