Troubleshooting and Maintaining the 1990 Case Poclain 170C: Pilot Controls

[MikePhua]

The 1990 Case Poclain 170C excavator is a robust and reliable piece of machinery, known for its powerful performance in demanding construction and digging applications. One of the key features of the 170C is its pilot controls, which allow operators to precisely manage the machine’s movements. However, like any heavy equipment, pilot controls can sometimes encounter issues, leading to difficulties in operating the machine.
In this article, we will explore common issues with the pilot controls on the 1990 Case Poclain 170C, how to troubleshoot them, and offer tips for maintaining this system to ensure optimal performance.
Understanding Pilot Controls on the Case Poclain 170C
Pilot controls are hydraulic systems used to manage the movement of the machine’s booms, arms, and undercarriage. On the Case Poclain 170C, the pilot controls provide a smooth, responsive operation, ensuring that the operator has precise control over the machine’s actions. These controls typically use low-pressure hydraulic fluid to transmit the operator’s inputs to the hydraulic actuators, allowing for smoother, more intuitive operation than traditional mechanical linkages.
While pilot controls offer excellent performance, they are also more complex than standard controls, requiring careful maintenance and attention to avoid operational issues. Common issues with pilot controls include erratic behavior, unresponsive movement, and system malfunctions, all of which can impede work and potentially damage the machine.
Common Problems with Pilot Controls
Several issues can arise with the pilot controls on the Case Poclain 170C, ranging from simple hydraulic fluid problems to more complex mechanical failures. Here are the most common problems operators may face:

1. Unresponsive Pilot Controls
   One of the most frustrating problems with pilot controls is when they become unresponsive, meaning the machine’s movements don’t react as expected to the operator’s input. This issue can stem from a variety of causes:
   • Low Hydraulic Fluid Levels: If the hydraulic fluid levels are too low, the system may not be able to transmit the required pressure, leading to sluggish or unresponsive control movements.
     
   • Hydraulic Fluid Contamination: Dirt, debris, or moisture in the hydraulic fluid can cause blockages or affect the performance of the hydraulic pumps and valves.
     
   • Faulty Control Valves: If the pilot control valves are malfunctioning or dirty, the hydraulic pressure might not be regulated correctly, leading to unresponsive controls.
     
   Solution: Check and maintain proper hydraulic fluid levels, and replace the fluid if it's contaminated. Regularly inspect and clean the control valves, and replace them if necessary.
   
2. Erratic Movements
   Sometimes, the pilot controls on the 170C may cause erratic or inconsistent movements, where the machine moves in an unpredictable manner even with smooth operator inputs. This can be a sign of:
   • Air in the Hydraulic System: Air bubbles in the hydraulic lines can cause the control system to behave erratically, resulting in jerky or unpredictable movements.
     
   • Faulty Pilot Control Valve: A malfunctioning pilot control valve might not correctly regulate the hydraulic pressure, causing inconsistent movement.
     
   • Clogged Filters: Clogged hydraulic filters can impede the flow of hydraulic fluid, affecting the smooth operation of the controls.
     
   Solution: Bleed the hydraulic system to remove any air pockets. Inspect and clean the hydraulic filters regularly and replace them if they are clogged or worn. If erratic movements persist, check the pilot control valves for faults.
   
3. Hydraulic Leaks
   Another common issue with pilot controls is hydraulic leaks, which can cause a drop in pressure and lead to performance problems. Leaks in the hydraulic lines, hoses, or control valves can impair the system's ability to function properly.
   Solution: Regularly inspect the hydraulic lines and components for visible leaks. Tighten or replace any loose or damaged connections and ensure that the hoses are free from cracks or wear.
   
4. Pilot Pressure Issues
   If the pilot pressure is too low or too high, it can cause issues with the responsiveness of the pilot controls. Low pressure may result in sluggish or non-reactive movements, while high pressure can lead to system damage or overly sensitive controls.
   Solution: Ensure that the pilot pressure is set correctly according to the manufacturer’s specifications. Adjust or replace the pressure regulating valves if necessary.
   
5. Control Lever Wear
   Over time, the control levers can become worn, leading to imprecise or loose controls. This can affect the operator’s ability to make fine adjustments to the machine’s movements.
   Solution: Inspect the control levers for wear and replace any components that show signs of significant damage. Lubricate moving parts to maintain smooth operation.
   

Troubleshooting the Pilot Controls
To troubleshoot issues with the pilot controls on your 1990 Case Poclain 170C, follow these steps:

1. Check Hydraulic Fluid Levels
   • Start by checking the hydraulic fluid levels and topping them up if necessary. Also, inspect the fluid for signs of contamination, such as discoloration or debris. If the fluid is dirty, drain and replace it with fresh, clean fluid.
     
2. Inspect Hydraulic Filters
   • Check the hydraulic filters for blockages. If they are clogged, clean or replace them. This will help restore proper fluid flow and prevent erratic movements.
     
3. Examine Pilot Control Valves
   • Inspect the pilot control valves for any signs of wear or malfunction. If the valves are dirty or faulty, clean or replace them to ensure proper regulation of hydraulic pressure.
     
4. Bleed the Hydraulic System
   • If you suspect air is trapped in the hydraulic system, bleed the system according to the manufacturer’s guidelines to remove any air pockets that could be causing erratic movement.
     
5. Check for Leaks
   • Perform a thorough inspection of the hydraulic hoses, lines, and valves for signs of leakage. Tighten any loose connections and replace any worn or damaged hoses.
     
6. Test the Pilot Pressure
   • Verify that the pilot pressure is within the correct range. If the pressure is too low or too high, adjust the regulating valve to the proper setting.
     
7. Inspect the Control Levers
   • Inspect the control levers for wear. If the levers are loose or damaged, replace them to restore precision in your control inputs.
     

Maintaining the Pilot Control System for Longevity
To keep the pilot control system on the Case Poclain 170C functioning optimally and to extend its lifespan, follow these maintenance tips:

1. Regular Fluid Checks
   Ensure that the hydraulic fluid is regularly checked and replaced at recommended intervals. This will prevent contamination and ensure smooth control operation.
   
2. Clean the Hydraulic System
   Keep the hydraulic system clean by regularly changing filters and cleaning the control valves. This will help prevent clogging and reduce the risk of erratic movements.
   
3. Inspect Hoses and Connections
   Routinely inspect hydraulic hoses and connections for signs of wear or leaks. Tighten any loose fittings and replace any cracked or worn hoses to avoid hydraulic pressure loss.
   
4. Adjust Pilot Pressure as Needed
   Regularly check and adjust the pilot pressure to ensure optimal control performance. Keeping pressure within the manufacturer’s recommended range will help prevent control issues.
   
5. Lubricate Moving Parts
   Ensure that all moving parts of the control levers and hydraulic components are properly lubricated to reduce friction and wear.
   

Conclusion: Keeping Your Case Poclain 170C in Top Shape
The 1990 Case Poclain 170C excavator is a durable and reliable machine, but like all heavy equipment, it requires proper maintenance to avoid issues with the pilot control system. By regularly checking hydraulic fluid levels, inspecting filters and valves, and addressing any leaks or wear, you can keep your machine running smoothly and avoid costly repairs.
Routine inspections and maintenance will help ensure that your Case Poclain 170C continues to perform at its best, maximizing productivity and reducing downtime. By following the troubleshooting steps and maintaining the hydraulic system properly, you’ll be able to enjoy the full capabilities of your machine for years to come.