Bleeding Brake Lines on the Case 580C Backhoe Loader

[MikePhua]

The Case 580C and Its Hydraulic Brake System
The Case 580C backhoe loader was introduced in the late 1970s as part of Case Corporation’s legendary 580 series, which became one of the most widely used compact construction machines in North America. With a diesel engine producing around 60 horsepower and a mechanical shuttle transmission, the 580C was built for trenching, loading, and site preparation. Its hydraulic brake system, designed for simplicity and reliability, uses dual master cylinders and wheel cylinders to actuate internal wet disc brakes.
Unlike modern machines with pressurized brake assist or electronic diagnostics, the 580C relies on manual bleeding and mechanical feedback. As these machines age, air intrusion into the brake lines becomes a common issue, especially after hose replacement, cylinder rebuilds, or fluid reservoir service.
Terminology Notes

• Master Cylinder: A hydraulic pump actuated by the brake pedal that sends fluid to the wheel cylinders
  
• Wheel Cylinder: A hydraulic actuator at each wheel that applies pressure to the brake discs
  
• Brake Fluid Reservoir: A tank that stores hydraulic fluid for the brake system
  
• Bleeder Screw: A valve located on the wheel cylinder used to release air from the brake lines
  
• Pedal Fade: A condition where the brake pedal sinks slowly under pressure due to air or internal leakage
  

Symptoms of Air in the Brake Lines
Operators of the 580C often report:

• Soft or spongy brake pedal feel
  
• Pedal travel increases with repeated use
  
• Reduced braking force on slopes or under load
  
• Brake pedal returns slowly or inconsistently
  
• Fluid overflow or bubbling in the reservoir during operation
  

These symptoms typically indicate trapped air in the hydraulic lines or incomplete fluid fill. In one case, a contractor in Missouri noticed his 580C rolling slightly on inclines despite full pedal depression. After bleeding both rear wheel cylinders, the brakes regained full holding power.
Bleeding Procedure and Safety Precautions
Before bleeding the brakes:

• Park the machine on level ground and chock the wheels
  
• Fill the brake fluid reservoir with DOT 3 or compatible hydraulic fluid
  
• Clean the bleeder screws to prevent contamination
  
• Use clear tubing and a catch bottle to monitor air bubbles
  
• Have a second person assist with pedal operation
  

Bleeding steps:

• Start with the wheel farthest from the master cylinder (typically right rear)
  
• Attach tubing to the bleeder screw and submerge the other end in fluid
  
• Have the assistant depress the brake pedal slowly and hold
  
• Open the bleeder screw to release fluid and air, then close
  
• Repeat until no air bubbles appear and pedal feel improves
  
• Move to the opposite wheel and repeat the process
  
• Top off the reservoir after each cycle to prevent air re-entry
  

If the system still feels spongy, inspect for worn seals, cracked hoses, or internal bypass in the master cylinder.
Additional Inspection Points
Beyond bleeding, check:

• Brake pedal linkage for free movement and proper return
  
• Reservoir cap seal for vacuum integrity
  
• Wheel cylinder boots for leaks or tears
  
• Fluid color and clarity—should be amber and free of debris
  
• Brake disc wear and adjustment if applicable
  

A technician in Alberta discovered that his 580C’s brake pedal was sticking due to a bent return spring. After replacement, the pedal returned smoothly and allowed proper bleeding.
Preventive Maintenance Recommendations
To maintain brake performance:

• Inspect fluid level weekly and top off as needed
  
• Replace brake fluid every 1,000 hours or annually
  
• Bleed the system after any hose or cylinder replacement
  
• Lubricate pedal linkage and inspect springs quarterly
  
• Keep bleeder screws capped and clean to prevent corrosion
  

For machines operating in wet or muddy environments, consider installing protective boots over the wheel cylinders to reduce contamination.
Stories from the Field
A road crew in Kentucky used a 580C for culvert installation. After replacing a rear wheel cylinder, they noticed poor braking during downhill travel. Bleeding the system revealed trapped air and sediment in the line. After flushing and refilling, the machine held firm even on steep grades.
In another case, a farmer in Oregon rebuilt both master cylinders on his 580C after noticing inconsistent pedal pressure. He used a vacuum bleeder to purge the system and reported that the brakes felt better than they had in years.
Conclusion
Bleeding the brake lines on a Case 580C is a vital maintenance task that restores safety and control. With proper technique, clean fluid, and attention to pedal behavior, operators can eliminate air from the system and ensure reliable braking performance. As these machines continue to serve in fields and job sites, maintaining the hydraulic brake system remains essential to their longevity and safety.