Troubleshooting Hydraulic Problems in the Bobcat S70: A Comprehensive Guide

[MikePhua]

The Bobcat S70 is a compact, highly versatile skid steer loader, ideal for working in tight spaces and performing a variety of tasks across construction, landscaping, and material handling applications. However, like all machinery, the S70 is prone to wear and tear, and hydraulic issues are a common cause of concern for operators. Hydraulic systems are critical to the operation of key functions like lifting, steering, and operating attachments, and problems with this system can cause significant downtime and decreased productivity.
In this article, we will delve into common hydraulic problems in the Bobcat S70, the likely causes behind these issues, and how to diagnose and fix them to get your machine back up and running smoothly.
Understanding the Hydraulic System in the Bobcat S70
The Bobcat S70, like most skid steers, operates using a closed-loop hydraulic system. This system consists of various components, including a hydraulic pump, hydraulic fluid, valves, hoses, and actuators that control the movement of the loader’s arms, bucket, and other attachments. The system relies on pressurized fluid to transmit force and perform the machine’s functions. Any malfunction in the system can result in reduced performance or complete failure of these critical functions.
The most common hydraulic-related issues in the S70 are related to fluid levels, pump performance, leaks, and wear on key components. Understanding these issues and how to troubleshoot them can save both time and money in the long run.
Common Hydraulic Problems in the Bobcat S70

1. Slow or Unresponsive Hydraulic Functions
   

Slow or unresponsive hydraulic movements can indicate issues such as low hydraulic fluid levels, a malfunctioning hydraulic pump, or clogged filters. When the hydraulic system is not delivering enough fluid pressure, the machine may struggle to lift, tilt, or move attachments as quickly or smoothly as usual.
Solution:

• Check the hydraulic fluid level. If it’s low, top it up with the appropriate type of hydraulic fluid. Be sure to use the manufacturer-recommended fluid to avoid damage to the system.
  
• Inspect the hydraulic filters for clogging. Dirty filters can restrict fluid flow, so cleaning or replacing the filters may solve the issue.
  
• Test the hydraulic pump to ensure it is operating at full capacity. If the pump is not delivering the correct pressure, it may need to be repaired or replaced.
  

1. Hydraulic Leaks
   

Hydraulic fluid leaks are a common problem that can lead to a loss of pressure and a gradual decline in performance. Leaks may occur in hoses, fittings, valves, or seals. Identifying the source of the leak is crucial, as even a small leak can eventually cause major problems if left untreated.
Solution:

• Inspect all hydraulic hoses for signs of cracks, cuts, or wear. Tighten or replace any loose or damaged fittings.
  
• Check the seals on the hydraulic cylinders and valves. If they are worn or damaged, replace them to prevent further leaks.
  
• If the leak is coming from the hydraulic pump or valve block, these components may need to be serviced or replaced.
  

1. Overheating Hydraulic System
   

An overheating hydraulic system can be caused by several factors, including clogged hydraulic coolers, low fluid levels, or excessive load on the system. Overheating can cause the hydraulic fluid to break down, leading to poor lubrication and increased wear on components.
Solution:

• Inspect the hydraulic cooler for dirt, debris, or blockages that could be restricting airflow. Clean the cooler to ensure it is working efficiently.
  
• Ensure the hydraulic fluid is at the correct level and is in good condition. Contaminated or old fluid should be replaced.
  
• If the system continues to overheat under normal operating conditions, consider reducing the load or using the machine in less demanding tasks.
  

1. Erratic Hydraulic Movement
   

Erratic or jerky movements from the S70’s hydraulics can result from issues with the hydraulic valves, pressure regulator, or control levers. If the system fails to respond smoothly, it could also indicate air in the hydraulic lines, low fluid pressure, or faulty solenoid valves.
Solution:

• Check for air in the hydraulic system by bleeding the air from the lines. Air can cause the hydraulic fluid to lose its pressure, resulting in inconsistent movements.
  
• Inspect the hydraulic valves for sticking or damage. Cleaning or replacing faulty valves may resolve the issue.
  
• Verify that the control levers are properly adjusted and that there is no obstruction or damage causing erratic control responses.
  

1. Hydraulic Pump Failure
   

The hydraulic pump is a key component of the system, responsible for pressurizing the fluid and driving the hydraulic functions of the S70. If the pump is faulty or worn out, it may fail to provide enough pressure to operate the machine’s hydraulics effectively.
Solution:

• Measure the pressure output of the hydraulic pump with a pressure gauge. If the pressure is lower than specified, the pump may be worn or damaged.
  
• If the pump is malfunctioning, it will likely need to be rebuilt or replaced. Consult the operator’s manual for specifications on the hydraulic pump and its pressure requirements.
  

1. Contaminated Hydraulic Fluid
   

Contaminated hydraulic fluid is a common issue that can lead to various hydraulic problems, such as clogged filters, damaged seals, and pump wear. Contaminants like dirt, water, and metal shavings can enter the system through faulty seals or damaged hoses, causing damage to sensitive components.
Solution:

• Perform a hydraulic fluid change if the fluid appears dirty, cloudy, or has a burnt smell. Replace the fluid with the recommended type and quantity.
  
• Change the hydraulic filters as well to remove any contaminants and prevent further damage to the system.
  
• Regularly check the fluid quality and replace it on a schedule to avoid buildup of harmful contaminants.
  

Steps to Diagnose Hydraulic Problems in the Bobcat S70
To effectively diagnose and fix hydraulic problems in the Bobcat S70, follow these steps:

1. Check Hydraulic Fluid Levels:
   The first step in diagnosing hydraulic issues is to check the fluid level. Low fluid is one of the most common causes of hydraulic performance issues. If the fluid is low, add the recommended fluid and check for leaks.
   
2. Inspect the Hydraulic Filters:
   A clogged filter can restrict fluid flow, leading to low pressure and slow performance. Inspect the filters and replace them if necessary. Make sure to use the correct filter type for the S70.
   
3. Test Hydraulic Pressure:
   Use a pressure gauge to test the hydraulic pressure at the pump and various points in the system. If the pressure is too low, the pump or other components may be malfunctioning.
   
4. Inspect for Leaks:
   Look for hydraulic fluid leaks along the hoses, fittings, and seals. Even small leaks can cause significant issues over time. Tighten or replace any faulty components.
   
5. Check the Hydraulic Cooler:
   If the system is overheating, inspect the hydraulic cooler for blockages or dirt buildup. Clean or replace the cooler as needed.
   
6. Test the Hydraulic Pump:
   If you suspect pump failure, check the pump’s performance using a pressure gauge. If the pump is not delivering the required pressure, it may need to be repaired or replaced.
   

Preventing Hydraulic Issues in the Bobcat S70
Regular maintenance is the key to preventing hydraulic issues in the Bobcat S70. Here are a few best practices:

1. Routine Fluid Checks:
   Regularly check the hydraulic fluid level and condition. Replace the fluid as needed and always use the recommended type.
   
2. Keep Hydraulic Hoses and Fittings Clean:
   Inspect and clean the hydraulic hoses and fittings regularly to prevent dirt and contaminants from entering the system.
   
3. Monitor Pressure:
   Periodically test the hydraulic system’s pressure to ensure that the pump and other components are working correctly.
   
4. Regular Filter Replacement:
   Change the hydraulic filters at the recommended intervals to keep the system clean and efficient.
   

Conclusion: Keeping the Bobcat S70 Hydraulic System in Top Shape
The Bobcat S70 is a powerful and reliable machine, but like any equipment, it requires regular attention to keep the hydraulic system operating at its best. By diagnosing hydraulic issues early, addressing them promptly, and performing routine maintenance, you can extend the life of the machine and minimize costly repairs. A well-maintained hydraulic system ensures smooth, reliable performance on the job site, helping to keep your operations running efficiently and without unexpected downtime.