If your John Deere R4023 sprayer boom isn’t folding up, you’re not alone. Boom folding issues are common in self-propelled sprayers, especially after extended use or when hydraulic components wear out. In this guide, we’ll walk you through the most likely causes, how to troubleshoot the problem, and what steps to take to get your R4023 boom folding properly again.
How the Boom Folding System Works on the R4023
The John Deere R4023 uses an electro-hydraulic system for boom folding. With the push of a button in the cab, hydraulic valves are activated via solenoids to fold or unfold the boom arms. This makes operation smooth and efficient—when everything works correctly.
- Controlled via in-cab CommandARM or joystick
- Hydraulic cylinders extend or retract the outer booms
- Solenoid valves open or close based on switch input
- Position sensors monitor boom location for feedback
Top Reasons Your R4023 Boom Won’t Fold Up
1. Faulty Boom Control Switch or Console Input
First 40–50 words for snippet: A common reason the boom won’t fold is a faulty switch or unresponsive console. If the in-cab control isn’t sending a proper signal, the hydraulics won’t activate.
- Check the boom fold switch for physical damage or loose wiring
- Use diagnostic mode to test switch response
- If the switch fails, replace the unit or test with a known good one
2. Solenoid Valve or Coil Malfunction
Each hydraulic function is controlled by a solenoid valve. If the solenoid that controls boom folding is stuck, burned out, or disconnected, it won’t open and allow hydraulic pressure through.
- Listen for a click at the solenoid when the button is pressed
- Use a multimeter to test for 12V at the solenoid coil
- Clean connectors or replace damaged coils as needed
3. Hydraulic Pressure or Flow Problem
The folding mechanism relies on consistent hydraulic pressure. If your main hydraulic supply is low, or if there’s a restriction, the boom won’t move.
- Check your hydraulic reservoir level and refill if low
- Inspect filters—clogged filters can choke pressure to boom functions
- Look for kinked or damaged hydraulic hoses
4. Faulty Boom Position Sensor or Lock
The system may prevent folding if it doesn’t detect the boom is in the correct pre-fold position. A failed sensor can stop the folding sequence entirely.
- Check the boom angle or position sensors for wiring damage or misalignment
- Use the monitor to check for sensor faults or diagnostic codes
- Recalibrate the boom if needed via the display settings
5. Hydraulic Cylinder Failure or Mechanical Obstruction
It’s possible the boom cylinder is leaking internally or physically stuck. Debris, bent pins, or metal fatigue can prevent smooth movement.
- Visually inspect boom pivot joints, pins, and linkages
- Manually extend or retract the boom (carefully) to check for resistance
- Check for signs of leaking or damaged cylinder seals
Diagnostic Steps to Follow
- Engage the parking brake and ensure engine RPM is within spec
- Cycle the boom switch and listen for any valve or hydraulic response
- Open the hydraulic panel and test solenoid power with a multimeter
- Check error messages on the in-cab display for any alerts
- Try folding the opposite boom side to isolate if the issue is one-sided
Preventative Maintenance Tips
- Grease boom pivot points weekly to prevent mechanical binding
- Check hydraulic fluid levels and change filters per the service interval
- Keep electrical connectors clean and moisture-free
- Inspect wiring harnesses and hoses after each season
- Cycle the booms during preseason setup to catch issues early
Still Having Problems?
If you’ve run through the diagnostics and your boom still won’t fold, it might be time to contact your local John Deere dealer. Technicians can run deeper diagnostics using JD Service Advisor, which checks software glitches, sensor calibration, and valve response more accurately.
Want More Practical Sprayer Help?
If you’re troubleshooting sprayers or maintaining your equipment year-round, click here to explore our expert sprayer maintenance guides and tutorials. We make it easier to diagnose, fix, and optimize your equipment on the farm.
Conclusion
When the boom on your John Deere R4023 sprayer refuses to fold, it usually comes down to electrical or hydraulic faults. Start by checking the boom switch, solenoids, and sensors. Make sure your hydraulic pressure is in range and inspect for any physical obstructions. With routine maintenance and smart troubleshooting, you can get your sprayer folding and functioning reliably again.
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