Understanding Brake System Issues on the 680H Loader

[MikePhua]

The 680H loader, a powerful piece of heavy machinery used primarily in construction, mining, and material handling, has earned its place as a reliable workhorse. However, like all complex machinery, it can experience mechanical issues over time. One of the most common concerns among 680H operators is the performance and reliability of its brake system. Understanding the brake system, recognizing potential issues, and knowing how to address them are essential to maintaining the loader's performance and ensuring safety on the job.
The Importance of the Brake System
The brake system in any heavy equipment, including the 680H loader, plays a vital role in ensuring operator control, safety, and the machine’s overall functionality. A malfunctioning brake system can lead to dangerous operating conditions, inefficiency, or even costly repairs. Given the heavy loads these machines often carry, the brake system must work flawlessly to prevent accidents and guarantee smooth operation.
In the case of the 680H, the brake system involves hydraulic components that engage and release the braking pressure, helping the machine to come to a stop when needed. The loader uses a combination of foot pedals and hand controls to manage braking, which is common for this type of equipment.
Common Brake Problems on the 680H Loader
When discussing brake issues with the 680H, there are a few common symptoms that operators might notice. These include:

1. Weak or Inconsistent Braking Power: This is one of the most frequently mentioned problems. Weak braking power might present itself as a delay in stopping or a sensation of “soft” brakes. This could be caused by air in the hydraulic system, low brake fluid, or worn-out brake components.
   
2. Unusual Noises: A squealing or grinding sound when braking could indicate worn brake pads or misalignment within the brake system. These noises should be addressed immediately to avoid further damage to the system.
   
3. Brake Pedal Sticking or Not Returning to Position: If the brake pedal is slow to return or sticks in a depressed position, there could be an issue with the brake linkage or hydraulic pressure. This could lead to overheating or a lack of full braking function, potentially putting the operator and surrounding personnel at risk.
   
4. Leaks in the Hydraulic System: Hydraulic leaks can affect the brake system’s performance by lowering the pressure necessary to operate the brakes. Leaks can occur in the brake lines or master cylinder, leading to a loss of braking power.
   
5. Overheating: Excessive braking over prolonged periods, such as when operating in a hilly or mountainous terrain, can lead to brake overheating. This can cause brake fade, where the braking power diminishes as the brake components heat up.
   

Diagnosing Brake Issues in the 680H
To diagnose brake issues accurately on a 680H loader, operators and technicians should follow a systematic approach:

1. Check Brake Fluid Levels: Low brake fluid levels can significantly impact braking performance. Ensure that the brake reservoir is full and that the fluid is clean. Dirty or contaminated fluid should be replaced.
   
2. Inspect Hydraulic Lines for Leaks: Examine the hydraulic lines for any signs of leakage or cracks. Hydraulic fluid leaks can weaken the brake system’s performance. If there are any visible leaks, they should be repaired promptly.
   
3. Test Brake Pedal Pressure: A soft or spongy brake pedal could indicate air in the system or low hydraulic pressure. Bleeding the hydraulic system may be necessary to remove air pockets.
   
4. Examine Brake Pads and Shoes: Over time, the brake pads or shoes can wear down. Check for excessive wear, cracks, or glazing. Replacing worn brake components is essential for maintaining optimal braking power.
   
5. Look for Overheating Signs: If the brakes are excessively hot to the touch or if there is a noticeable drop in braking efficiency, this may be an indication of overheating. Proper cooling and ensuring that the machine isn’t overloaded can help prevent this.
   

Maintaining the Brake System
Preventative maintenance is key to ensuring the longevity and reliability of the brake system on the 680H loader. Some key maintenance tips include:

1. Regular Fluid Checks: Consistently check the brake fluid levels and quality. Hydraulic systems rely on clean, adequate fluid to function properly. Always top off the fluid as needed and replace it if it becomes contaminated.
   
2. Bleed the System Regularly: If you notice any signs of air in the hydraulic lines (such as a soft brake pedal), it's essential to bleed the system to remove the air and restore proper brake performance.
   
3. Clean the System: Dirt and debris can damage the hydraulic components and reduce the efficiency of the brake system. Regular cleaning of the brake components, especially after working in dusty or dirty environments, can help prolong the life of the system.
   
4. Inspect Brake Pads and Components: Routine inspections of the brake pads, shoes, and other related components can catch wear and tear before it becomes a problem. Replacing worn components before they fail is critical to maintaining safe operation.
   
5. Avoid Overloading: Overloading the loader or applying brakes too aggressively on steep slopes can cause overheating and accelerated brake wear. Operators should be mindful of the load limits and brake system cooling during operation.
   

Common Fixes and Repairs
When issues are identified in the brake system, it’s important to fix them quickly to avoid further complications. Common repairs for the 680H loader’s brake system include:

1. Replacing Worn Brake Pads or Shoes: Over time, brake pads or shoes will wear down. Replacing them as part of regular maintenance can restore braking efficiency.
   
2. Repairing or Replacing Hydraulic Lines: Leaks in the hydraulic system should be addressed immediately. Damaged lines can be repaired or replaced to restore full hydraulic pressure.
   
3. Bleeding the Hydraulic System: If air is present in the hydraulic lines, it can compromise braking. Bleeding the system removes the air and restores proper function.
   
4. Addressing Overheating: In cases of brake overheating, it may be necessary to allow the brakes to cool down, reduce excessive braking, or replace any components that have become damaged due to heat.
   
5. Fixing Sticking Pedals: Sticking brake pedals are often caused by faulty linkage or hydraulic pressure issues. These parts should be cleaned or replaced to ensure smooth operation.
   

Conclusion
Maintaining a properly functioning brake system is critical for the safe operation of the 680H loader. Regular maintenance, timely repairs, and attention to detail can prevent brake failure and ensure the machine continues to perform efficiently. Operators and technicians should always be proactive in checking for issues, such as low fluid levels, hydraulic leaks, or worn brake components, and take appropriate action to keep the loader in optimal working condition.