08-29-2025, 02:04 AM
Introduction
The Mustang 960 skid steer loader, manufactured in the early 1990s, is renowned for its durability and versatility in various construction and agricultural applications. However, like all machinery, it is susceptible to mechanical issues over time. One such common problem is jerky steering and intermittent right-side drive failure. Understanding the potential causes and solutions is essential for maintaining optimal performance.
Hydrostatic Drive System Overview
The Mustang 960 operates using a hydrostatic drive system, which relies on hydraulic fluid to transmit power from the engine to the wheels. This system offers smooth acceleration and deceleration, making it ideal for skid steer loaders. Key components include the hydraulic pump, drive motors, control valves, and relief valves. Any malfunction in these components can lead to steering issues or drive failures.
Common Causes of Jerky Steering and Drive Failure
- Hydraulic Fluid Contamination or Low Levels
Contaminated or insufficient hydraulic fluid can cause erratic steering and drive behavior. Debris or air in the hydraulic lines can obstruct flow, leading to inconsistent power delivery. Regularly checking and replacing the hydraulic fluid and filters can prevent such issues.
- Faulty Steering Control Valve
The steering control valve directs hydraulic fluid to the appropriate drive motors. If this valve becomes worn or sticky, it may not properly allocate fluid, resulting in jerky steering or loss of drive on one side. Inspecting and cleaning or replacing the valve can resolve this problem.
- Drive Motor Malfunction
Each wheel is powered by a hydraulic drive motor. A malfunction in the right-side drive motor, such as internal wear or a sticking shuttle valve, can cause intermittent drive failure. Swapping the drive motors between sides can help diagnose if the motor is at fault.
- Relief Valve Issues
The relief valve regulates the maximum pressure within the hydraulic system. If the relief valve is set too low or is malfunctioning, it can cause erratic hydraulic behavior, including jerky steering. Checking and adjusting the relief valve pressure to manufacturer specifications can alleviate this issue.
- Sprocket and Chain Wear
Worn sprockets or chains, particularly on the right side, can lead to power loss and jerky movement. Regular inspection and maintenance of the drive chains and sprockets are crucial for smooth operation.
- Hydraulic Fluid Check
- Ensure the hydraulic fluid is at the proper level and is clean.
- Replace the fluid and filters if contamination is present.
- Ensure the hydraulic fluid is at the proper level and is clean.
- Steering Control Valve Inspection
- Listen for unusual noises when steering, indicating a potential valve issue.
- Clean or replace the steering control valve if necessary.
- Listen for unusual noises when steering, indicating a potential valve issue.
- Drive Motor Testing
- Swap the right-side drive motor with the left-side motor.
- If the problem shifts to the left side, the motor is likely faulty.
- Swap the right-side drive motor with the left-side motor.
- Relief Valve Adjustment
- Use a pressure gauge to check the relief valve setting.
- Adjust the valve to the correct pressure as per the service manual.
- Use a pressure gauge to check the relief valve setting.
- Sprocket and Chain Inspection
- Check for wear or damage to the sprockets and chains.
- Replace any worn components to ensure proper power transmission.
- Check for wear or damage to the sprockets and chains.
- Regular Fluid Changes: Change the hydraulic fluid and filters at intervals recommended by the manufacturer to prevent contamination and ensure smooth operation.
- Component Lubrication: Lubricate moving parts, including the steering control valve and drive motors, to reduce wear and tear.
- System Bleeding: Periodically bleed the hydraulic system to remove air pockets that can cause erratic behavior.
- Component Inspection: Regularly inspect the steering and drive components for signs of wear or damage, addressing issues promptly to prevent further complications.
Jerky steering and intermittent right-side drive failure in the Mustang 960 skid steer loader can stem from various hydraulic and mechanical issues. By systematically diagnosing the problem and performing regular maintenance, operators can ensure the longevity and reliability of their equipment. Addressing these issues promptly not only restores functionality but also enhances safety and efficiency on the job site.
