Hydraulic Drive Failure and Boom Access on the John Deere 317 Skid Steer

[MikePhua]

The John Deere 317 and Its Compact Powertrain
The John Deere 317 skid steer loader was introduced in the mid-2000s as part of Deere’s expansion into compact construction equipment. With a 61 hp diesel engine and a rated operating capacity of 1,750 pounds, the 317 was designed for versatility across landscaping, agriculture, and light construction. Its hydrostatic drive system and auxiliary hydraulics made it compatible with a wide range of attachments, including clam shell buckets, augers, and trenchers.
Built with a low-profile frame and a tilting operator station, the 317 allows access to its hydraulic components beneath the cab. However, when hydraulic failure occurs—especially involving the boom or drive system—accessing these components becomes a challenge, particularly if the boom is stuck in the lowered position.
Symptoms of Hydraulic Drive Failure
One operator reported a sudden pop while driving the machine, followed by complete loss of drive power on the right side. Upon inspection, hydraulic fluid was leaking from beneath the machine. The left side continued to function, suggesting a localized failure in the right-side drive circuit.
Common symptoms include:

• Loss of drive power on one side
  
• Visible hydraulic fluid leak
  
• Inability to raise the boom due to hydraulic pressure loss
  
• No warning lights or fault codes
  

These signs point to a ruptured hydraulic hose or a damaged charge pump, which supplies low-pressure fluid to the hydrostatic system.
Terminology and Component Overview
- Hydrostatic Pump: A variable displacement pump that powers the drive motors via pressurized hydraulic fluid.
- Charge Pump: A smaller pump that feeds low-pressure fluid to the hydrostatic pump, maintaining system pressure and cooling.
- Clam Shell Bucket: A hinged bucket attachment that opens and closes like a clamshell, often used for grabbing debris or material.
- Boom Lock: A mechanical safety device that secures the boom in a raised position for maintenance access.
Accessing the Cab with a Disabled Boom
With the boom lowered and hydraulics disabled, raising the operator station requires manual intervention. The boom must be elevated enough to engage the boom lock before the cab can be tilted. In this case, the operator used two bottle jacks placed under the rear pivot pins of the boom. By slowly and evenly pumping both jacks, the boom was raised incrementally, with cinder blocks used for bracing and safety.
Once the boom was high enough, the lock was engaged, and the cab was lifted to inspect the hydraulic system. This method, while effective, requires caution and should only be performed with proper support and safety measures.
Root Cause and Hose Specification Error
Inspection revealed that a hydraulic hose feeding the right-side drive motor had ruptured at the pump connection. The hose had previously been replaced by a third party and was improperly constructed. Specifically:

• The hose was ¾" diameter rated at 3,500 psi
  
• All OEM hoses from Deere were ⅝" diameter rated at 4,000 psi
  
• The failed hose had poorly crimped fittings, leading to separation under pressure
  

This mismatch in hose specification and poor assembly contributed directly to the failure. Replacing the hose with a properly rated ⅝" 4,000 psi unit resolved the issue.
Recommendations for Hydraulic Hose Replacement
When replacing hydraulic hoses:

• Match OEM diameter and pressure ratings exactly
  
• Use certified crimping equipment and fittings
  
• Inspect all hoses for abrasion, kinking, and fitting integrity
  
• Flush the system after replacement to remove debris
  
• Replace the hydraulic filter and refill with fresh fluid
  

In this case, the operator replaced the hose, installed a new hydraulic filter, and refilled the system with clean oil. The machine returned to full operation without further issues.
Design Oversight and Pressure Spike Risks
One technician noted that the John Deere 317 lacks a circuit relief valve in the auxiliary hydraulic section. When using attachments like clam shell buckets, pressure spikes can travel back through the system and damage the charge pump. This design oversight has led to multiple failures in similar machines.
Recommendations include:

• Installing an aftermarket relief valve in the auxiliary circuit
  
• Avoiding sudden impact with attachments (e.g., hitting curbs)
  
• Monitoring hydraulic temperature and pressure during operation
  

Conclusion
Hydraulic failure in the John Deere 317 can be traced to hose specification errors, pressure spikes, and design limitations. With careful manual boom lifting, proper hose replacement, and system flushing, the machine can be restored to service. In compact loaders, precision in hydraulic components isn’t optional—it’s the difference between uptime and downtime. And when the boom won’t lift, ingenuity becomes the first tool in the box.