Case IH 1955-07 - UCM – UCM: Rear Pilot Head #4 is reporting that the spool valve is stuck

The control module commands the #4 remote to move, but the feedback sensor detects that the spool valve has not reached its commanded position. This is typically caused by mechanical binding within the valve body, hydraulic fluid contamination jamming the spool, or an internal electrical/mechanical failure of the pilot head itself.

• MAGNUM AFS Connect
• Steiger Series (400, 450, 500, 550, 600)
• Quadtrac Series (470, 500, 540, 580, 620)
• Magnum Series (290, 340)
• Puma Series (165, 180, 195, 210, 225)

1. 1

   Check the hydraulic fluid for contamination and ensure cold oil relief cartridges and filters are intact and not bypassed.

2. 2

   Inspect the wiring harness leading to the #4 remote pilot head, paying close attention to the main harness in the articulation joint for chafing or wear at the 'P' clamps on articulated tractors.

3. 3

   Perform a component isolation swap test by swapping the #4 pilot head with an adjacent working remote (e.g., #3) to determine if the fault follows the pilot head or remains on the mechanical spool valve.

1. 1

   Depressurize

   Turn off the tractor and relieve all hydraulic pressure from the system by cycling the remote levers/switches.

2. 2

   Disconnect

   Disconnect the electrical harness connector from the #4 rear pilot head.

3. 3

   Remove Pilot Head

   Remove the hex socket screws (typically M8 x 40mm) securing the pilot head to the auxiliary control valve body. Carefully lift the pilot head assembly off the valve stack.

4. 4

   Inspect and Clean

   Inspect the mechanical spool valve and the bore. If it is stuck due to contamination, clean the pilot spools and free them up in their bores using brake cleaner. Important OEM Note: Do not use abrasives (like sandpaper or emery cloth) on the spool or the spool bore, as this will ruin the tight machining tolerances.

5. 5

   Replace

   If the pilot head is internally failed (as proven by the swap test), install a new or remanufactured pilot head assembly.

6. 6

   Reassemble

   Secure the pilot head with the mounting screws and reconnect the electrical harness.

7. 7

   Calibration

   After installing a new pilot head, you must perform a valve calibration through the tractor's UCM/display menu (often found in the 'HH' or 'HK' calibration menus). This allows the controller to learn the new valve's travel limits and neutral deadband.