Troubleshooting Hydraulic Issues in the Bobcat 843 Skid Steer Loader

[MikePhua]

The Bobcat 843 skid steer loader is a versatile machine known for its power, agility, and efficiency in various construction and agricultural applications. However, like any piece of heavy equipment, the Bobcat 843 is susceptible to hydraulic issues that can disrupt its performance. Hydraulic problems in particular can severely impact the machine's lifting capacity, mobility, and overall functionality.
In this article, we will delve into the common hydraulic issues that can affect the Bobcat 843, the steps for troubleshooting these problems, and the recommended solutions to get your skid steer loader back in top condition.
Understanding the Hydraulic System of the Bobcat 843
Before troubleshooting hydraulic issues, it's essential to understand how the hydraulic system in the Bobcat 843 operates. The hydraulic system is responsible for powering the loader's lifting arms, bucket, and wheels, as well as other essential functions.

• Hydraulic Pump: This component generates the hydraulic pressure needed to operate the various functions of the skid steer.
  
• Hydraulic Valves: The valves control the flow of hydraulic fluid to different parts of the system, directing the fluid to the appropriate components based on the operator’s input.
  
• Hydraulic Cylinders: These are used for lifting the arms and operating the bucket. Cylinders convert hydraulic fluid pressure into mechanical force.
  
• Hydraulic Hoses and Lines: These carry the hydraulic fluid throughout the system, connecting the pump, valves, and cylinders.
  

The hydraulic fluid circulates through the system, transferring power to the necessary components to allow the Bobcat 843 to perform a wide range of tasks.
Common Hydraulic Problems in the Bobcat 843
Several hydraulic issues can affect the Bobcat 843, leading to reduced performance or even total failure of certain functions. Below are some of the most common hydraulic problems:

1. Loss of Hydraulic Power
   A common issue is the loss of hydraulic power, where the loader may struggle to lift loads or move its arms and bucket. This can be caused by several factors, including low hydraulic fluid levels, clogged filters, or issues with the hydraulic pump.
   
2. Slow or Uneven Response
   When operating the loader's arms or bucket, the response may be slow or uneven. This can result from air in the hydraulic system, dirty fluid, or malfunctioning valves.
   
3. Hydraulic Leaks
   Leaking hydraulic fluid is another common problem. It could be a result of damaged hoses, faulty seals, or worn-out cylinders. Leaks can lead to a drop in hydraulic pressure, rendering the loader unable to perform as expected.
   
4. Noisy Hydraulic System
   If the hydraulic system makes unusual noises, such as whining, grinding, or hissing, it could indicate an issue with the hydraulic pump, contamination in the fluid, or air in the system.
   
5. Erratic Lifting or Arm Movement
   If the lifting arms or bucket of the Bobcat 843 move erratically or hesitate to respond, this could be a sign of air bubbles in the hydraulic fluid, a malfunctioning valve, or a failing pump.
   

Step-by-Step Troubleshooting Process
If you are experiencing any of the above hydraulic issues, it’s crucial to troubleshoot systematically to identify the root cause. Below is a step-by-step guide for diagnosing and resolving common hydraulic problems in the Bobcat 843.
Step 1: Check Hydraulic Fluid Levels
The first step in diagnosing hydraulic issues is to check the hydraulic fluid level. Low fluid levels are one of the most common causes of poor hydraulic performance. To check the fluid:

• Locate the hydraulic fluid reservoir and remove the dipstick or cap.
  
• Check the fluid level against the recommended marks on the dipstick.
  
• If the fluid is low, top it up with the correct type of hydraulic fluid as specified in the Bobcat 843 manual.
  

If you find that the fluid level is consistently low, this could indicate a leak somewhere in the system, which should be addressed immediately.
Step 2: Inspect for Hydraulic Leaks
Hydraulic leaks can cause a significant loss of pressure, leading to poor performance. Carefully inspect the entire hydraulic system for signs of leaks. Look for:

• Wet spots around hydraulic hoses, fittings, or cylinders.
  
• Damp areas near the pump or valve block.
  
• Puddles of fluid on the ground beneath the loader.
  

If you find any leaks, it’s essential to repair or replace the damaged parts. Tighten any loose fittings or replace cracked hoses and seals to prevent further loss of fluid.
Step 3: Examine the Hydraulic Fluid for Contamination
Contaminated hydraulic fluid can cause various issues, including erratic performance and damage to the system components. To check for contamination:

• Inspect the fluid color and consistency. Healthy hydraulic fluid is typically clear or slightly amber. If the fluid appears dark or has particles floating in it, it’s likely contaminated.
  
• If contamination is found, perform a hydraulic fluid change. Drain the old fluid and replace it with the appropriate hydraulic fluid recommended by Bobcat for the 843 model.
  

It is also important to replace the hydraulic filters if they are clogged or dirty. Clogged filters can impede the flow of fluid and reduce hydraulic performance.
Step 4: Test the Hydraulic Pump
A malfunctioning hydraulic pump can cause a loss of power or slow response. To test the pump:

• Start the engine and listen for any unusual noises coming from the pump. A whining or grinding sound may indicate damage.
  
• Check the hydraulic pressure using a pressure gauge. Refer to the Bobcat 843 manual for the correct pressure specifications.
  

If the pressure is too low or the pump is making strange noises, the pump may need to be repaired or replaced.
Step 5: Inspect Hydraulic Valves and Cylinders
The hydraulic valves control the flow of fluid to the lifting arms, bucket, and other parts of the loader. If these valves malfunction, they can cause slow or uneven movement. To check the valves:

• Test the operation of the bucket and arms. If they are slow or don’t respond consistently, the valves may be clogged, damaged, or misadjusted.
  
• Check the cylinders for any signs of leakage or physical damage.
  

If the valves are dirty, clean or replace them as necessary. If the cylinders are leaking or damaged, they may need to be resealed or replaced.
Step 6: Bleed the Hydraulic System
If air has entered the hydraulic system, it can cause slow or jerky movements. To remove air from the system, follow the procedure outlined in the Bobcat 843 manual for bleeding the system. This typically involves opening certain valves and allowing the system to purge air while the engine is running.
Step 7: Perform a Hydraulic Pressure Test
If the above steps don’t resolve the issue, performing a hydraulic pressure test can help pinpoint the problem. Use a pressure gauge to test the pressure at various points in the hydraulic system. This can help determine whether the pump, valves, or other components are malfunctioning.
Repairing Hydraulic Issues in the Bobcat 843
Once you’ve identified the problem, it’s time to take action. The most common repairs involve replacing or repairing the following components:

• Hydraulic Pump: If the pump is damaged or malfunctioning, it will need to be replaced. A professional technician can help replace the pump and ensure it is properly calibrated.
  
• Hydraulic Hoses and Fittings: Leaky hoses should be replaced immediately to prevent further fluid loss. Ensure that new hoses are properly fitted and securely fastened.
  
• Hydraulic Valves and Cylinders: If the valves are clogged or damaged, they may need cleaning, adjustment, or replacement. Damaged cylinders should be resealed or replaced.
  
• Hydraulic Fluid and Filters: Regularly changing the hydraulic fluid and filters can prevent many common issues. Make sure to use the correct fluid for your Bobcat 843 to ensure smooth operation.
  

Preventive Maintenance Tips
To avoid hydraulic issues in the future, follow these preventive maintenance tips:

1. Regular Fluid Checks: Frequently check the hydraulic fluid levels and top them up as needed.
   
2. Scheduled Fluid Changes: Change the hydraulic fluid and filters every 500 to 1000 hours of operation, depending on the manufacturer’s recommendations.
   
3. Inspect Hoses and Fittings: Regularly inspect hydraulic hoses, fittings, and seals for signs of wear or leaks.
   
4. Proper Storage: Store the machine in a clean and dry environment to prevent dirt and contaminants from entering the hydraulic system.
   
5. Avoid Overloading: Always follow the manufacturer’s guidelines for maximum load capacity to prevent unnecessary strain on the hydraulic system.
   

Conclusion
Hydraulic issues in the Bobcat 843 skid steer loader can significantly affect its performance and productivity. By understanding the common hydraulic problems and following a systematic troubleshooting process, operators can quickly diagnose and resolve these issues. Regular maintenance, such as checking fluid levels, inspecting hoses, and replacing filters, can help prevent these problems from occurring in the first place.
With proper care and attention, the Bobcat 843’s hydraulic system can continue to operate at peak efficiency, ensuring that the machine remains a reliable and valuable asset in your fleet.