CAT 246B Brake Issues: Brakes Not Holding When Engine Is Running

[MikePhua]

One of the common issues on equipment like the CAT 246B skid steer loader is the inability of the brakes to hold the machine stationary when the engine is running. This can create significant safety concerns and operational inefficiencies. This article will explore the possible causes of this issue and provide solutions to resolve it.
Possible Causes

1. Brake Fluid Leaks
   A leak in the brake hydraulic fluid is one of the most common reasons for brakes not holding when the engine is running. Leaks can occur in the brake lines, master cylinder, or brake calipers, causing a loss of hydraulic pressure and ultimately preventing the brakes from working effectively.
   
2. Air in the Brake System
   If there is air trapped in the brake system, it can lead to brake failure or delayed braking response. When hydraulic fluid is compressed, the air can form bubbles, reducing the hydraulic pressure and causing the brakes to fail to hold the machine in place.
   
3. Faulty Brake Pump
   The brake pump is a critical component that provides the hydraulic pressure needed for braking. If the brake pump is not functioning properly or has failed, it will not generate enough pressure to engage the brakes effectively.
   
4. Hydraulic Fluid Quality Issues
   Poor-quality or degraded hydraulic fluid can affect the performance of the brake system. The viscosity and cleanliness of the fluid are essential for stable hydraulic pressure. Using old or contaminated fluid may lead to brake issues.
   
5. Worn Brake Components
   Over time, the brake components such as brake pads or discs can wear down, reducing the effectiveness of the braking system. If the brake components are worn out, the brakes may fail to hold properly, especially when the engine is running and the hydraulic pressure is fluctuating.
   

Solutions

1. Inspect Brake Fluid and Hydraulic System
   Begin by checking the brake hydraulic fluid for leaks. Inspect the master cylinder, brake calipers, and hydraulic lines for any signs of fluid loss. If leaks are found, repair or replace the damaged parts immediately. Also, check the fluid level and quality, and top off or replace the fluid as necessary.
   
2. Bleed the Brake System
   If air is suspected in the brake system, you can bleed the brakes to remove the trapped air. Follow the proper procedure for bleeding the brakes, either by using a brake bleeder kit or following the manufacturer’s guidelines for air removal.
   
3. Check and Replace the Brake Pump
   If the brake fluid is intact and there is no air in the system but the issue persists, the brake pump could be malfunctioning. Inspect the pump to see if it is generating the required hydraulic pressure. If the pump is not working properly, it may need to be replaced.
   
4. Replace Hydraulic Fluid
   If the hydraulic fluid is old or contaminated, it should be replaced with fresh, high-quality hydraulic oil. Clean fluid ensures the proper operation of the brake system and prevents wear on other components in the system.
   
5. Inspect and Replace Worn Brake Components
   Regularly check the brake pads and discs for wear. If the components are worn down, they should be replaced. Replacing worn brake components will not only improve braking performance but also prevent further damage to the brake system.
   

Conclusion
The inability of the CAT 246B brakes to hold when the engine is running is usually caused by brake fluid leaks, air in the brake system, a faulty brake pump, hydraulic fluid issues, or worn brake components. To address these issues, check for leaks, bleed the system to remove air, inspect and replace the brake pump, change the hydraulic fluid, and replace worn brake components. Regular maintenance and inspections will ensure that the brake system operates properly and prevent safety issues.