Water Delivery System and 777F WTR, 777G WTR and 785D WTR OEM Off-Highway Trucks Caterpillar

Water Cannon Does Not Function

Usage:

785D DMC

The possible causes of the cannon not working are listed below:

No oil pressure
Plugged cartridge valve
Bad hydraulic manifold
Broken harness

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Illustration 1	g03644441

Check Hydraulic Manifold Pressure
1. Install a 376-4170 Pressure Sensor from the 368-9910 Multi-Tool Group to the pressure inlet gauge port on the cannon hydraulic manifold.
2. Turn the key switch to the ON position and start the machine.
  Expected Result: The gauge port pressure should measure 3447 kPa (500 psi).
  Results:
  OK - The gauge port pressure reads 3447 kPa (500 psi). Proceed to Step 2.
  Not OK - Pressure is less than 3447 kPa (500 psi).
  Repair: Check the truck hoist valve pilot pressure at the hoist valve. The pressure should be 3447 kPa (500 psi). If the pressure is not within specification, check the hoist pilot circuit.
Check Hydraulic Pressure Going to the Cannon
1. Connect pressure gauge to pressure "UP" outlet port on the Cannon hydraulic manifold.
2. Turn the key switch to the ON position and start the machine.
3. Press the cannon button on the WDS keypad.
4. Move the cannon joystick to the full up position and record the pressure.
  Expected Result: The gauge port pressure should measure between 689 kPa (100 psi) and 3447 kPa (500 psi).
  Results:
  OK - The gauge port pressure reads between 689 kPa (100 psi) and 3447 kPa (500 psi). Proceed to Step 3.
  Not OK - Pressure is 0.0 kPa (0.0 psi) 0 psi or the pressure is low.
  Repair: Remove the cartridge valve. Clean the valve with solvent. Reinstall the cartridge valve and check for cannon movement. If the cannon does not move "UP," then proceed to Step 4.
  STOP.
Check Hydraulic Manifold
1. Turn the key switch to the OFF position.
2. Remove the "UP" solenoid valve from the hydraulic manifold.
3. Remove the plug from the gauge port and blow compressed air into the port.
  Expected Result: Air should flow freely from the "UP" port
  Results:
  OK - Air flows freely from the "UP" port. Proceed to Step 4.
  Not OK - No air flows from the "UP" port.
  Repair: Replace the hydraulic manifold.
Check Solenoid valve
1. Remove the "UP" solenoid valve from the hydraulic manifold.
2. Turn the key switch to the ON position and start the machine.
3. Press the cannon on button.
4. Move the joystick to the "UP" position.
5. Observe the movement of the solenoid valve.
  Expected Result: The spool of the solenoid valve moves smoothly.
  Results:
  OK - The spool of the solenoid valve moves smoothly. Proceed to Step 5.
  Not OK - The spool of the solenoid does not move as expected.
  Repair: Replace the solenoid valve.
Check Wiring Harness
1. Connect volt meter to solenoid positive and negative pins.
2. Turn the key start switch to the ON position. Measure the voltage
  Expected Result: The voltage reads approximately 24 V.
  OK - The voltage reads approximately 24 V.
  Not OK - Check the wiring harness.