Case 850B Dozer Brake Problems and Solutions

[MikePhua]

The Case 850B is a versatile and robust crawler dozer widely used in heavy construction, forestry, and earth-moving applications. However, like any mechanical equipment, the Case 850B is not immune to issues, and one of the most common problems that operators encounter is brake failure or reduced braking performance. When the brakes malfunction, it can cause safety concerns, inefficiency, and costly repairs if left unaddressed. In this article, we will delve into the common causes of brake issues in the Case 850B dozer, provide troubleshooting tips, and suggest practical solutions to restore proper braking function.
Understanding the Brake System in the Case 850B
The Case 850B dozer, like most crawler dozers, is equipped with a hydraulic brake system. The hydraulic brake system uses hydraulic pressure to activate brake components, which slow down or stop the machine’s tracks. The system relies on several key components to function correctly, including brake cylinders, hydraulic lines, the master cylinder, and various valves. When any part of this system fails or shows wear, it can lead to issues such as reduced braking force, spongy pedals, or total brake failure.
Common Brake Problems in the Case 850B Dozer

1. Spongy Brake Pedal: A spongy or soft brake pedal is a common issue in hydraulic brake systems. It occurs when there is air in the brake lines or when the brake fluid level is low. Air in the hydraulic system prevents the full transfer of pressure to the brake components, resulting in poor braking performance.
   
2. Brake Fluid Leaks: Leaks in the hydraulic brake system are a frequent cause of brake problems. Hydraulic fluid can leak from brake lines, seals, or cylinders. A drop in fluid levels due to leaks can lead to inadequate braking force, and if left unchecked, it can cause total brake failure.
   
3. Brake Wear and Tear: Over time, the brake pads and brake discs in the 850B will wear down from continuous use. Worn-out brake components reduce the efficiency of the braking system and can make stopping the machine more difficult, especially under heavy loads.
   
4. Clogged or Contaminated Brake Lines: Dirt, debris, and contaminants can accumulate in the hydraulic lines, blocking fluid flow and impeding the proper functioning of the brake system. Contaminated brake fluid can also cause corrosion in brake components, leading to further system degradation.
   
5. Faulty Master Cylinder: The master cylinder is a critical part of the braking system that generates hydraulic pressure to activate the brake cylinders. A malfunction in the master cylinder can result in a loss of brake pressure, leading to weak or non-functional brakes.
   
6. Worn or Damaged Brake Cylinders: Brake cylinders are responsible for converting hydraulic pressure into mechanical force to engage the brakes. Over time, the seals in the brake cylinders can wear out, leading to leakage or insufficient braking force.
   
7. Incorrect Brake Adjustment: Improper adjustment of the brake linkage or pedal can result in inefficient braking. If the linkage is not adjusted correctly, the brake pads may not fully engage with the discs, reducing braking effectiveness.
   

Diagnosing Brake Problems
When experiencing brake issues with your Case 850B, it's important to follow a structured diagnostic process to identify the cause of the problem. Below are the steps you should take to diagnose brake issues:

1. Inspect the Brake Pedal: If the brake pedal feels soft or spongy, it could indicate air in the brake lines or low fluid levels. Check the brake fluid reservoir and ensure it’s at the recommended level. If fluid is low, top it up and check for leaks.
   
2. Check for Fluid Leaks: Inspect the brake lines, cylinders, seals, and fittings for any signs of leakage. Leaks can often be traced by looking for wet spots or stains around the hydraulic components. If a leak is detected, it’s essential to repair it immediately.
   
3. Inspect Brake Fluid Quality: Old or contaminated brake fluid can lead to poor brake performance. Check the color and condition of the brake fluid. If the fluid appears dark or contains visible contaminants, it’s time for a brake fluid flush and replacement.
   
4. Check Brake Pad and Disc Condition: Remove the brake covers and inspect the brake pads and discs for signs of excessive wear or damage. Worn brake pads will need to be replaced, while discs should be resurfaced or replaced if they are grooved or warped.
   
5. Inspect the Master Cylinder: Check the master cylinder for signs of leaks or wear. If the cylinder is damaged or not generating proper pressure, it may need to be replaced.
   
6. Test the Hydraulic System: Use a hydraulic pressure gauge to test the brake system’s pressure. If the pressure is low, there could be an issue with the hydraulic pump, valves, or brake lines. You may also want to check the pump for wear or malfunction.
   
7. Examine the Brake Cylinders: Inspect the brake cylinders for leakage or corrosion. If the seals are damaged, they will need to be replaced to restore brake function.
   
8. Verify Brake Adjustment: Ensure that the brake linkage is properly adjusted. If necessary, adjust the linkage so that the brake pads fully engage the brake discs when the pedal is pressed.
   

Solutions to Common Brake Problems

1. Bleed the Brake System: If the brake pedal is spongy, you may need to bleed the brake system to remove air from the hydraulic lines. This involves loosening the bleeder valve on each brake cylinder and allowing the air to escape until clean, bubble-free brake fluid flows out.
   
2. Repair Brake Fluid Leaks: Leaks can often be fixed by tightening loose fittings, replacing damaged hoses, or replacing worn seals. If the leak is more severe, it may be necessary to replace the entire brake line or cylinder.
   
3. Replace Worn Brake Pads and Discs: If the brake pads are worn down, replace them with new ones. Inspect the brake discs for any signs of damage, such as warping or scoring, and replace them if necessary.
   
4. Flush and Replace Brake Fluid: If the brake fluid is contaminated, perform a full brake fluid flush and replace it with fresh fluid. This will help restore proper hydraulic pressure and prevent further corrosion in the system.
   
5. Repair or Replace the Master Cylinder: If the master cylinder is malfunctioning, it may need to be replaced or repaired. Ensure that it is properly sealed and functioning correctly to generate sufficient hydraulic pressure.
   
6. Clean the Hydraulic Lines: If the hydraulic lines are clogged or contaminated, clean them thoroughly or replace them if necessary. Use only clean, high-quality hydraulic fluid to prevent further contamination.
   
7. Adjust the Brake Linkage: If the brake linkage is misaligned, adjust it to ensure that the brake pads are fully engaging with the discs. This will improve braking efficiency and performance.
   

Preventive Maintenance
To prevent future brake problems with your Case 850B dozer, it is crucial to follow a regular maintenance schedule. This includes:

• Regular brake fluid checks and changes: Replace brake fluid every 1,000 hours or as recommended by the manufacturer.
  
• Inspecting brake components: Check brake pads, cylinders, and discs for wear and replace them before they cause significant issues.
  
• Cleaning hydraulic lines and components: Keep the brake system free from dirt, debris, and contaminants to maintain smooth hydraulic operation.
  
• Checking for leaks: Periodically inspect all brake components for leaks and repair them promptly to avoid fluid loss and system failure.
  

Conclusion
Brake issues in the Case 850B dozer can cause operational delays, safety concerns, and potentially expensive repairs if not addressed promptly. By understanding the common causes of brake problems, following a structured diagnostic process, and performing necessary repairs and maintenance, you can ensure that your dozer operates safely and efficiently. Regular maintenance and timely repairs are essential to extending the life of your equipment and preventing more severe issues from arising in the future.