Case IH 1979-07 - UCM – UCM: Rear pilot head #6 reporting that the spool valve is stuck

The electronic pilot head mounted on top of the #6 rear remote valve has detected that the internal spool valve is not moving as commanded. This condition is most commonly caused by hydraulic oil contamination (dirt or debris) sticking the pilot spools in their bores, or a mechanical/electrical failure within the pilot head itself.

• MAGNUM AFS Connect
• Steiger AFS Connect
• Puma CVX series

1. 1

   Inspect hydraulic fluid and filters for contamination. Ensure filters are clean and cold oil relief/bypass cartridges are intact to prevent dirty oil from bypassing directly to the system valves.

2. 2

   Verify hydraulic pressure reaching the valve and check if spool movement is physically restricted.

3. 3

   Isolate the component to determine if the issue is a physically stuck main spool in the valve body or a faulty pilot head giving erroneous readings.

1. 1

   Clean the stuck spool

   If the spool is stuck due to debris, remove it and clean the spool and its bore using brake cleaner and a soft brush (such as a toothbrush). CRITICAL: Do NOT use any abrasives on either the spool or the spool bore.

2. 2

   Lubricate the spool

   Lubricate the spool with clean hydraulic oil before reassembly.

3. 3

   Remove the end cover

   If the main spool is worn or damaged and requires replacement, remove the end cover located at the opposite end of the remote valve section from the pilot head. Save the two O-rings found under the cover so they can be reused.

4. 4

   Replace the main spool

   Carefully remove the main flow control spool from the remote valve section. Lubricate the new improved main spool with hydraulic oil and reassemble the valve section.

5. 5

   Reinstall the end cover

   Install the two saved O-rings and tighten the six valve spool cover screws to 27–31 Nm (19–22 lb-ft).

6. 6

   Replace the pilot head

   If the pilot head itself has failed, remove the screws securing it to the top of the remote valve and install the new pilot head assembly.

7. 7

   Calibrate the remote valves

   CRITICAL CALIBRATION: If you replace the pilot head, you must reassign the remote valves through the tractor's display (often referred to as the 'H menu') and calibrate the valves. If this is not done, the new pilot head will not work and the tractor will immediately throw an offline code for that remote.