JCB 8035 ZTS Only Dozer Blade Functions – Troubleshooting and Solutions

[MikePhua]

The JCB 8035 ZTS is a compact and highly versatile mini excavator designed for construction, landscaping, and small-scale excavation projects. Known for its efficiency and reliability, this machine is often used for tasks in tight spaces where larger machinery can’t operate. However, like any piece of heavy equipment, it can sometimes encounter operational issues that affect its performance. One such issue is when the machine’s dozer blade operates correctly, but other functions, such as the boom, arm, and bucket, stop working.
This article aims to explore the possible causes for this specific issue in the JCB 8035 ZTS and provide troubleshooting methods and solutions to get the machine back to full functionality.
Understanding the JCB 8035 ZTS
The JCB 8035 ZTS is part of JCB's range of compact excavators, offering a balance of power, precision, and maneuverability. Equipped with a 33.5-horsepower engine and a hydraulic system that provides excellent lifting capabilities, this machine is known for its ability to handle tasks such as trenching, lifting, and grading in areas with limited space.
Despite its small size, the JCB 8035 ZTS features a zero tail swing (ZTS) design, which allows for enhanced flexibility and operation in confined areas. The excavator comes equipped with various functions like the dozer blade for leveling and grading, and a hydraulic arm for digging and lifting tasks.
The Issue: Only the Dozer Blade Works
A situation where only the dozer blade functions correctly, but the other controls (boom, arm, bucket) are unresponsive, typically indicates a hydraulic system issue. The problem could stem from a variety of factors, including hydraulic valve malfunctions, issues with the hydraulic pump, or electrical faults. Let’s break down the potential causes in more detail.
Potential Causes of the Issue

1. Hydraulic Valve Malfunction
   

The hydraulic system on the JCB 8035 ZTS uses a series of valves to control the flow of hydraulic fluid to various components, including the boom, arm, bucket, and dozer blade. A malfunction in one of these valves could cause a situation where only certain functions receive fluid pressure, while others do not. The dozer blade might be on a separate valve circuit, allowing it to continue operating even when other parts of the hydraulic system fail.

1. Hydraulic Pressure Loss
   

A loss of hydraulic pressure is one of the most common reasons for a lack of movement in the excavator's arm, boom, and bucket. If the hydraulic pump is not generating enough pressure or if there is a blockage in the hydraulic lines, the machine will fail to perform specific operations, while others, like the dozer blade, may still function because they are powered by a different hydraulic circuit.

1. Electrical or Control System Fault
   

The JCB 8035 ZTS is equipped with an electronic control system that regulates the hydraulic valves and other machine functions. If there is an issue with the wiring, sensors, or the control module, it could cause the system to misinterpret signals, leading to some functions working while others do not. This can be especially problematic if the electrical connections to the hydraulic valve solenoids are faulty or disconnected.

1. Hydraulic Fluid Contamination or Low Fluid Levels
   

Contaminated hydraulic fluid or low fluid levels can cause a loss of power in the hydraulic system, leading to poor performance or failure of certain functions. If the hydraulic fluid is contaminated, it can clog filters, valves, and other parts of the hydraulic system, which could explain why only certain parts of the machine, like the dozer blade, remain functional.
Troubleshooting Steps
If you’re experiencing this issue with your JCB 8035 ZTS, follow these steps to troubleshoot the problem and potentially resolve the issue:

1. Check Hydraulic Fluid Levels and Quality
   

Start by checking the hydraulic fluid levels. Low fluid levels are a common cause of hydraulic system issues. Make sure the fluid is at the recommended levels and that it’s clean. If the fluid appears dirty or contaminated, it may need to be replaced. You should also inspect the hydraulic filter and replace it if it’s clogged.

1. Inspect Hydraulic Valves
   

Next, inspect the hydraulic valves that control the boom, arm, and bucket. These valves are often located near the hydraulic pump or under the machine’s cab. Look for any signs of leaks or damage to the valve body. If there are issues with a valve, you may need to replace or clean it to restore normal function.

1. Test Hydraulic Pressure
   

If the hydraulic fluid levels and valves appear to be fine, the next step is to test the hydraulic pressure. Use a pressure gauge to check the pressure at the hydraulic pump and compare it to the specifications provided in the operator’s manual. If the pressure is low, it could indicate a problem with the pump, such as wear or internal damage, which would require repair or replacement.

1. Inspect Electrical System and Wiring
   

If the hydraulic system seems to be functioning correctly, but the boom, arm, and bucket still don’t work, there may be an electrical issue. Check the wiring, connectors, and fuses related to the hydraulic control system. Look for any loose or damaged connections that could prevent the electronic control system from properly activating the hydraulic valves.

1. Check the Control Joystick or Lever
   

The control system that operates the boom, arm, and bucket is typically controlled via joysticks or levers. If there’s an issue with the joystick or the control lever's electronic components, it could prevent the functions from working properly. Inspect the joystick for any visible damage or wear and ensure that it is properly connected to the machine’s control system.

1. Run a Diagnostic Test
   

If you’ve gone through the above steps and the problem persists, consider using a diagnostic tool to scan the machine’s electronic control system for any fault codes. This could help pinpoint issues with sensors, solenoids, or the control module, allowing you to address the problem more precisely.
Common Solutions and Fixes

1. Replace or Clean Hydraulic Valves: If a malfunctioning valve is identified, cleaning or replacing the faulty valve should restore full functionality to the boom, arm, and bucket.
   
2. Hydraulic Pump Repair or Replacement: A low-pressure issue typically means the hydraulic pump is failing. Replacing or repairing the pump will likely resolve the issue.
   
3. Electrical System Repair: Tightening loose connections, replacing damaged wires, or addressing faulty sensors in the electrical system may fix the problem. If the control module is malfunctioning, it might need to be reprogrammed or replaced.
   
4. Fluid Replacement and Filtration: Regularly replacing the hydraulic fluid and filter is essential for maintaining the hydraulic system. Contaminated fluid should be flushed out and replaced to ensure smooth operation.
   

Preventative Measures
To prevent this issue from happening in the future, it is essential to maintain the JCB 8035 ZTS in optimal condition. Here are some preventative maintenance tips:

• Regularly check and replace hydraulic fluid: Make sure the fluid is clean and at the proper level.
  
• Inspect hydraulic lines and valves periodically: Look for wear, leaks, or any signs of damage.
  
• Keep the electrical system in good condition: Check for loose wires, corroded connections, or damaged sensors.
  
• Follow a regular maintenance schedule: Adhere to the manufacturer’s maintenance recommendations to ensure all parts of the excavator, from the hydraulic system to the electrical components, are functioning properly.
  

Conclusion
The JCB 8035 ZTS is a powerful, compact excavator that offers great versatility on the job site. However, when issues arise—such as only the dozer blade functioning while the boom, arm, and bucket fail—there are several potential causes, from hydraulic pressure loss to electrical system faults. By systematically troubleshooting the hydraulic system, electrical components, and control valves, operators can identify and resolve the issue. Regular maintenance, including fluid checks and timely repairs, will ensure the longevity and optimal performance of the machine.