Restoring Power Steering on the International 2400 Backhoe

[MikePhua]

The International 2400 and Its Hydraulic Legacy
The International Harvester 2400 backhoe-loader was part of IH’s push into the compact utility equipment market during the 1970s and early 1980s. Built for municipal work, farm use, and light construction, the 2400 featured a rugged frame, mechanical simplicity, and a hydraulically driven steering system. International Harvester, founded in 1902, had already earned a reputation for durable agricultural tractors and industrial machines. The 2400 was powered by a four-cylinder diesel engine and used a gear-driven hydraulic pump to supply fluid to the loader, backhoe, and steering circuits.
Though production numbers were modest compared to competitors like Case and Ford, the 2400 earned a loyal following among operators who valued its straightforward design and ease of repair. Today, many units remain in service, especially in rural areas where mechanical reliability is prized over electronic sophistication.
Understanding the Hydraulic Filter and Steering Circuit
The hydraulic system on the 2400 includes multiple filters, one of which is located on the left side of the machine and incorporates a fine mesh screen. This filter is responsible for trapping debris before fluid enters sensitive components like the steering valve and hydraulic cylinders. When this filter is changed, it’s essential to refill the hydraulic fluid not only in the main reservoir but also in the filter housing itself.
Failure to refill the filter housing can lead to air entrapment in the steering circuit. Since the power steering relies on uninterrupted hydraulic pressure, any air pockets can cause the system to lose responsiveness or fail entirely. This is especially common after filter changes, hose replacements, or fluid flushes.
Symptoms of Air in the Steering System
Operators may notice the following signs:

• Steering wheel turns freely with no resistance
  
• Loader and backhoe functions operate normally
  
• No visible leaks or broken lines
  
• Fluid level appears correct in the reservoir
  

These symptoms suggest that the steering valve is not receiving adequate pressure due to air blockage or an unprimed filter housing.
Steps to Restore Steering Function
To resolve the issue:

• Remove the hydraulic filter again and pre-fill the housing with clean hydraulic fluid
  
• Reinstall the filter and ensure all seals are properly seated
  
• Start the engine and let it idle for several minutes to allow fluid circulation
  
• Turn the steering wheel slowly left and right to purge air from the system
  
• Check fluid level in the reservoir and top off as needed
  

If the steering does not return after these steps, inspect the following:

• Hydraulic pump output pressure (should exceed 1,500 psi under load)
  
• Steering control valve for internal leakage or sticking spools
  
• Return lines for obstructions or collapsed hoses
  
• Filter bypass valve for proper operation
  

In one case, a technician in South Carolina discovered that a newly installed filter had an internal blockage due to manufacturing debris. Replacing the filter with a verified clean unit restored steering immediately.
Preventative Measures and Maintenance Tips
To avoid future issues:

• Always pre-fill hydraulic filters before installation
  
• Use OEM or high-quality aftermarket filters with verified mesh ratings
  
• Change hydraulic fluid every 500 hours or annually, whichever comes first
  
• Inspect hoses and fittings for wear or cracking
  
• Keep the reservoir cap sealed to prevent moisture ingress
  

Adding a sight glass or dipstick to the reservoir can help monitor fluid levels more accurately. Some operators install a small inline pressure gauge on the steering circuit to verify system health during startup.
Stories from the Field
A farmer in Nichols, South Carolina shared his experience with a 2400 backhoe that lost steering after a routine filter change. Initially suspecting a pump failure, he consulted a retired IH mechanic who advised refilling the filter housing directly. After following the advice, the steering returned within minutes. The lesson: even simple maintenance tasks require attention to hydraulic flow paths.
In another case, a municipality in Iowa retrofitted their aging 2400 fleet with spin-on filters and quick-drain valves to simplify service. The upgrade reduced downtime and improved reliability, especially during winter operations when hydraulic fluid thickens.
Conclusion
The International 2400 remains a capable and serviceable machine decades after its release. Its hydraulic steering system, while robust, depends on proper fluid priming and filter maintenance. When steering fails after a filter change, the solution is often as simple as refilling the housing and purging air. With careful attention to hydraulic principles and routine upkeep, the 2400 continues to serve operators who value mechanical integrity and straightforward troubleshooting.