Restoring Fuel Delivery on a 1970 Case 580CK After Injector Pump Rebuild

[MikePhua]

The Case 580CK and Its Mechanical Legacy
The Case 580CK (Construction King) backhoe loader was a defining machine of the 1960s and 1970s, combining rugged simplicity with versatile performance. Built by J.I. Case Company, which had already established itself in agricultural equipment since the mid-1800s, the 580CK was designed for utility contractors, municipalities, and farmers needing a reliable loader-backhoe combo. With a mechanical diesel engine and gear-driven drivetrain, the 580CK was known for its ease of service and long operational life.
By 1970, the model had gained traction across North America, with thousands sold annually. Its diesel variant typically used a Roosa Master or CAV-style injection pump, which pressurized and timed fuel delivery to the engine’s cylinders. Over time, these pumps wear internally, leading to hard starts, fuel starvation, or erratic performance—necessitating a rebuild.
Terminology Notes

• Injection pump: A precision device that meters and pressurizes diesel fuel for timed delivery to each cylinder.
  
• Fuel rack: A mechanical control that adjusts fuel quantity based on throttle input.
  
• Governor: A mechanism that regulates engine speed by controlling fuel delivery.
  
• Bleed screw: A small valve used to purge air from the fuel system during priming.
  

Challenges After Rebuilding the Injector Pump
Reinstalling a rebuilt pump on a 580CK can be deceptively tricky. Common post-rebuild issues include:

• No fuel delivery due to improper priming
  
• Misaligned timing causing backfire or no start
  
• Stuck fuel rack from varnish or incorrect assembly
  
• Airlock in the lines preventing pressure buildup
  
• Solenoid or linkage binding preventing rack movement
  

Even with a freshly rebuilt pump, fuel may not reach the injectors if the system isn’t bled properly or if the rack is stuck in the shutoff position. This is especially true for older pumps that sat dry for extended periods before rebuild.
A Story from the Ontario Countryside
In 2016, a retired operator in Ontario rebuilt the injection pump on his 1970 Case 580CK after noticing sluggish throttle response and black smoke. After reinstalling the pump, the engine refused to start. He checked fuel lines, filters, and even swapped injectors—still no luck. Eventually, he removed the pump again and discovered the fuel rack was jammed due to a misaligned governor spring. After correcting the assembly and re-priming the system, the engine fired instantly. He said, “It wasn’t the pump—it was the patience.”
Step-by-Step Diagnostic and Setup Strategy
To ensure proper fuel delivery after pump rebuild:

• Confirm pump timing by aligning timing marks on the pump flange and engine gear housing
  
• Open all injector line nuts slightly to allow air purge during cranking
  
• Use the hand primer or electric lift pump to fill the pump body with fuel
  
• Crack the bleed screw and wait for steady fuel flow before tightening
  
• Check throttle linkage for full travel and return spring tension
  
• Manually inspect the fuel rack for free movement before installation
  
• Verify solenoid function if equipped—should click audibly when energized
  

If fuel still doesn’t reach injectors, remove the pump and bench test it with a hand crank or test stand. Look for rack movement, fuel discharge, and governor response.
Preventive Measures and Long-Term Care
To protect the rebuilt pump:

• Use clean diesel and replace filters every 250 hours
  
• Add fuel conditioner to prevent varnish and microbial growth
  
• Run the engine monthly during off-season to keep internals lubricated
  
• Avoid running the tank dry to prevent airlock and pump cavitation
  
• Inspect throttle and shutoff linkages annually for wear or binding
  

Some owners install clear fuel lines or sight glasses to monitor flow visually. Others retrofit electric lift pumps to improve priming and reduce strain on the mechanical system.
Choosing Rebuild Kits and Service Providers
When rebuilding a pump:

• Use kits with Viton seals for biodiesel compatibility
  
• Confirm plunger and barrel tolerances match OEM specs
  
• Replace governor springs and weights if worn
  
• Clean all internal passages with ultrasonic or solvent bath
  
• Avoid generic kits lacking part numbers or calibration data
  

Professional rebuilders often bench-test pumps for delivery rate, timing, and rack response. Ask for a test sheet or calibration report when possible.
Final Thoughts
Rebuilding the injector pump on a 1970 Case 580CK is a rewarding task—but only if done with precision and patience. The pump is the heart of the diesel system, and even minor misalignments can prevent fuel delivery. With careful assembly, proper timing, and thorough priming, the old Construction King can roar back to life. In vintage diesel work, success lies not in brute force—but in understanding the rhythm of fuel and fire.