Massey Ferguson A.4X.28: External Hydraulic Valve 4 Issue

Indicates a fault, often an electrical connection problem or mechanical failure, preventing the proper operation of the 4th external hydraulic remote/spool valve.

• 5710SL
• 5711SL
• 5712SL
• 5713SL
• T4
• 4707
• 4708
• 4709
• 4710
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• 7714
• 7715(S)
• 7716(S)
• 7718(S)
• 7719
• 7720(S)
• 7722(S)
• 7724(S)
• 7726(S)

1. 1

   Inspect the wiring harness and the electrical connector at External Hydraulic Valve 4 for corrosion, backed-out pins, or wire chafing (electrical cause).

2. 2

   Check the hydraulic fluid condition and filters, as dirty oil is a primary cause of spool sticking (mechanical cause).

3. 3

   Perform a physical inspection of the valve block for external oil leaks.

4. 4

   Verify if the remote service is weak or if the implement creeps, which indicates internal seal failure.

1. 1

   Relieve Pressure

   Ensure the tractor is off and relieve all hydraulic pressure from the remote valves before servicing.

2. 2

   Clean the Area

   Thoroughly clean the area around External Valve 4 to prevent dirt from entering the hydraulic system during removal.

3. 3

   Electrical Repair

   If the diagnostic check revealed a wiring issue, repair the harness or replace the pigtail connector to the valve solenoid. Clear the codes to see if 0A.4X.28 returns.

4. 4

   Valve Rebuild/Replacement

   If the electrical circuit is intact, the valve itself is faulty. Remove the spool valve assembly.

5. 5

   Reseal/Repair

   Depending on the damage, you can rebuild the valve using a spool valve repair kit (replacing the O-rings, detent kit, and return spring).

6. 6

   Reinstallation

   Reinstall the valve, reconnect the hydraulic lines and electrical harness, top off the hydraulic fluid, and test the remote for proper operation and leakages.