John Deere 455G (1987) Hydraulic Hammering Sound: Troubleshooting Guide

[MikePhua]

The John Deere 455G (1987) is a well-regarded wheel loader that has been in service for many years, providing reliable performance. However, like any older equipment, it can encounter issues that affect its functionality. One such issue is the hammering sound coming from the hydraulics, which can be concerning for operators. In this article, we explore the possible causes of hydraulic hammering in the John Deere 455G and provide troubleshooting tips to resolve the problem.
Understanding Hydraulic Hammering
Hydraulic hammering refers to a knocking or banging sound that occurs when the hydraulic system experiences pressure fluctuations or irregular flow. This sound can be a sign of an underlying problem, such as an issue with the hydraulic pump, valve, or system pressure. It’s crucial to identify the cause of the hammering, as continued operation with this issue can lead to more severe damage to the hydraulic components.
Common Causes of Hydraulic Hammering
Several factors can contribute to hydraulic hammering in the John Deere 455G:

1. Low Hydraulic Fluid Levels:
   Low hydraulic fluid can cause cavitation, where air bubbles form in the fluid, leading to inconsistent pressure and the hammering sound. Ensure that the hydraulic fluid is at the correct level and that the fluid is clean and free from contaminants.
   
2. Air in the Hydraulic System:
   Air in the hydraulic lines can cause cavitation and lead to erratic pressure changes, which may result in the hammering sound. This could happen if there’s a leak in the system, or if the hydraulic fluid has been recently changed and air was introduced during the process. Bleeding the system to remove any trapped air is essential for resolving this issue.
   
3. Faulty Hydraulic Pump:
   A worn or malfunctioning hydraulic pump can cause irregular pressure output, leading to hydraulic hammering. If the pump is not operating efficiently, it can result in surges or drops in hydraulic pressure, causing the knocking sound. Inspect the pump for signs of wear or damage and consider replacing it if necessary.
   
4. Dirty or Clogged Hydraulic Filters:
   Clogged filters can restrict hydraulic fluid flow, leading to inconsistent pressure in the system. This can cause a hammering noise as the fluid struggles to flow through the system properly. Check and clean or replace the hydraulic filters to ensure smooth fluid flow.
   
5. Faulty Hydraulic Valves:
   Hydraulic valves control the flow of fluid to various components in the system. If a valve is malfunctioning or sticking, it can cause pressure spikes or drops, resulting in hydraulic hammering. Inspect the valves for damage or wear and repair or replace them if necessary.
   

Troubleshooting Steps
To troubleshoot the hydraulic hammering issue in the John Deere 455G, follow these steps:

1. Check Fluid Levels:
   Start by inspecting the hydraulic fluid levels. If the fluid is low, top it up with the recommended fluid type. If the fluid appears dirty or contaminated, consider draining and replacing it.
   
2. Inspect for Air Leaks:
   Check the hydraulic lines, hoses, and connections for any signs of leaks. Air entering the system through a loose fitting or cracked hose can lead to cavitation and the hammering noise. Tighten any loose connections and replace any damaged hoses.
   
3. Bleed the Hydraulic System:
   If air has entered the hydraulic system, you’ll need to bleed the system to remove the trapped air. Follow the manufacturer's instructions for bleeding the system properly.
   
4. Examine the Hydraulic Pump:
   Inspect the hydraulic pump for signs of wear or damage. Look for any leaks around the pump and check for abnormal sounds when the system is in operation. If the pump is faulty, it may need to be repaired or replaced.
   
5. Inspect and Clean Hydraulic Filters:
   Remove and inspect the hydraulic filters for clogs or damage. Clean or replace the filters as necessary to ensure smooth fluid flow.
   
6. Check Hydraulic Valves:
   Inspect the hydraulic valves for any signs of wear or malfunction. If a valve is sticking or not operating correctly, it may need to be cleaned, repaired, or replaced.
   

Conclusion: Resolving Hydraulic Hammering in the John Deere 455G
Hydraulic hammering in the John Deere 455G is typically caused by issues with fluid levels, air in the system, or malfunctioning components like the pump or valves. By carefully troubleshooting the hydraulic system and addressing the root cause of the hammering, operators can restore smooth operation to the machine. Regular maintenance, including checking fluid levels, inspecting hoses and filters, and ensuring the hydraulic pump and valves are in good condition, is essential for preventing hydraulic issues and ensuring the longevity of the machine.