John Deere 710K Backhoe Hydraulic Loss and Steering Stick Diagnostic

Symptoms

• Steering wheel kicks back or locks when loader arm reaches top swing
• Loud hydraulic screaming noise from the front nose frame bulkhead
• Reduced cylinder speeds in backhoe boom and swing structures

Possible Causes

• Debris-stuck or broken spring in the steering priority valve spool
• Excessive internal load-sensing (LS) circuit feedback signal line leakage
• Failing primary main variable piston pump (swashplate stuck or internal wear)

Diagnostic Procedure

1. 1
   Perform System Standby Pressure Inspection

   Install 5,000 psi pressure gauge onto pump diagnostic main port. Record warm engine high-idle standby pressure. Spec reading should be approximately 350-400 psi. Lower readings suggest margin valve issues.
2. 2
   Verify Steering Priority Valve Operation

   Determine if steering takes absolute hydraulic precedence over other loader circuits. Remove and clean steering priority valve spool assembly. Inspect the main bore for scratches or metal particles.
3. 3
   Assess Load Sensing (LS) Line Pressures

   T-connect a gauge directly in line with the steering orbitrol feedback trace. Initiate heavy turn control and ensure LS signal matches work demand pressure to properly shift pump swashplate angle.
4. 4
   Test Hydraulic Pump Stroke Max Relief

   Bottom out loader cylinder at idle, then at high-speed engine setting. Confirm maximum relief cutoff reaches approximately 3,600 psi without stalling machine engine.

Common Repairs

• Polish or replace priority control valve internal slide spool
• Replace worn load sensing relief block assembly components
• Rebuild or swap out main hydraulic displacement pump unit

Safety Precautions

• Fully lock and secure backhoe stabilization arms and frame locks.
• Relieve complete system residual oil pressure to zero before opening lines.

Required Tools

• Hydraulic gauge test set (0-5,000 psi)
• T-adaptor hydraulic joint fittings
• Micrometer caliper measurements

Related Fault Codes

People Also Ask

• Why does my John Deere 710K steering kick back when lifting the loader?
• What causes a loud screaming noise from the front bulkhead on a JD 710K?
• How do you troubleshoot hydraulic fault codes HYD 0110-03 and HYD 0115-04?
• Where is the priority valve located on a John Deere 710K backhoe?
• What causes slow swing and boom cylinder speeds on a Deere 710K?
• How do I perform a standby pressure test on a 710K hydraulic pump?

Related Guides

Suggested Follow-Up Guides

• John Deere 710K Steering Priority Valve Rebuild and Adjustments
• How to Diagnose and Service JD 710K Hydrostatic Steering Orbitals
• John Deere PowerTech 6.8L Hydraulic Pump Installation and Priming
• Step-by-Step Pressure Testing of John Deere Closed-Center Hydraulic Systems
• Troubleshooting Backhoe Swing Cylinder Bypass and Seal Failure

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