Changing the Hydraulic Oil Filter on a John Deere 310D Backhoe

[MikePhua]

The John Deere 310D and Its Hydraulic System
The John Deere 310D backhoe loader, introduced in the early 1990s, was part of Deere’s highly successful 310 series. Known for its rugged build and dependable performance, the 310D featured a closed-center hydraulic system powered by a gear-type pump. This system provided consistent flow and pressure for both loader and backhoe functions, making it a favorite among contractors and municipalities. With thousands of units sold across North America, the 310D remains a workhorse in the field, especially in rural and utility applications.
The hydraulic system on the 310D relies heavily on clean fluid and proper filtration. Contaminants like metal shavings, dust, and moisture can quickly degrade seals, score cylinders, and clog valves. Regular filter changes are essential to maintain system integrity and prevent costly repairs.
Locating and Replacing the Hydraulic Filter
On the 310D, the hydraulic oil filter is mounted externally, typically on the right side of the machine near the loader frame. It’s a spin-on type, similar in appearance to an engine oil filter but designed for high-pressure hydraulic fluid. The filter housing is connected to the return line, meaning it captures contaminants before fluid re-enters the reservoir.
Steps for replacement:

• Park the machine on level ground and lower all implements
  
• Shut off the engine and relieve hydraulic pressure by cycling the controls
  
• Locate the filter housing and clean the area to prevent debris from entering
  
• Use a strap wrench or filter tool to remove the old filter
  
• Inspect the gasket surface and clean thoroughly
  
• Apply hydraulic oil to the new filter’s gasket and install by hand until snug
  
• Start the engine and check for leaks
  
• Monitor fluid level and top off if necessary
  

The recommended replacement interval is every 500 operating hours, though dusty or high-load environments may require more frequent changes.
Terminology Clarification
- Closed-Center System: A hydraulic design where fluid flow is stopped when controls are in neutral
- Return Line: The hydraulic line that carries fluid back to the reservoir after use
- Spin-On Filter: A self-contained filter unit that screws onto a threaded mount
- Gasket Surface: The metal ring where the filter seals against the housing
- Strap Wrench: A tool used to grip and remove cylindrical components like filters
Common Mistakes and Troubleshooting
Operators sometimes confuse the hydraulic filter with the transmission filter, especially on older machines with multiple spin-on units. Installing the wrong filter can restrict flow or cause bypass valve failure. Always verify the part number—John Deere typically uses a filter like AT101565 for the 310D, but aftermarket equivalents must match pressure and micron rating.
Another issue arises when the old gasket remains stuck to the housing. Installing a new filter over the old gasket can cause leaks or blowouts. Always inspect the sealing surface after removal.
If hydraulic functions become sluggish after a filter change, check for:

• Air trapped in the system
  
• Low fluid level
  
• Incorrect filter type
  
• Clogged suction screen in the reservoir
  

In one case, a contractor replaced the filter but forgot to refill the reservoir. The loader arms stalled mid-lift, and the backhoe wouldn’t swing. After topping off the fluid and bleeding the system, full function returned.
Preventive Maintenance and System Health
To extend the life of the hydraulic system:

• Use only clean, manufacturer-approved hydraulic oil
  
• Store fluid in sealed containers to prevent moisture contamination
  
• Replace filters on schedule and inspect for metal particles
  
• Keep breather caps and dipsticks clean
  
• Monitor for unusual noises, jerky movement, or overheating
  

Some operators install magnetic drain plugs or inline screens to catch early signs of wear. These additions can reveal pump degradation or cylinder scoring before symptoms appear.
Final Thoughts
The hydraulic system is the lifeblood of the John Deere 310D, powering everything from bucket curl to boom swing. A simple filter change, done correctly, protects thousands of dollars in components and keeps the machine working reliably. In the field, downtime is costly—and clean fluid is cheap insurance. Whether you're trenching for utilities or loading gravel, a well-maintained hydraulic system ensures the 310D delivers the performance it was built for.