Steering Clutch Adjustment on the Late 1950s John Deere 420 Crawler

[MikePhua]

The John Deere 420 Crawler, first introduced in the late 1950s, is a versatile and durable machine known for its use in various agricultural and industrial tasks. Like many of the era’s crawler tractors, the John Deere 420 features steering clutches, which are essential for controlling the machine’s direction. Proper adjustment of these clutches is crucial for ensuring smooth operation and prolonging the life of the machine. This article explores the process and importance of steering clutch adjustment on the John Deere 420 Crawler.
Understanding the Steering Clutch Mechanism
The steering clutches on a crawler tractor like the John Deere 420 are responsible for controlling the individual tracks. Each track is driven independently, allowing the operator to turn the machine by engaging or disengaging one of the clutches. This system is a fundamental part of how tracked vehicles like crawlers navigate, providing the maneuverability needed for tasks in tight spaces, on uneven terrain, and in demanding conditions.
In the John Deere 420, the steering clutch system consists of several key components:

1. Clutch Plates: These engage and disengage the power transfer to each track.
   
2. Pressure Springs: These springs ensure that the clutch plates remain engaged under normal conditions.
   
3. Linkage Mechanisms: The linkage connects the clutch lever to the clutch plates, allowing the operator to engage or disengage the clutch.
   
4. Bearings and Seals: These parts ensure smooth movement of the clutch and prevent dirt or moisture from damaging the system.
   

Proper adjustment of these components is essential for preventing slippage, uneven movement, and wear, all of which can lead to reduced performance or even mechanical failure.
Why Steering Clutch Adjustment Is Important
Over time, wear and tear can cause the steering clutches to lose their effectiveness, leading to difficulty in steering or uneven movement. Common symptoms of improperly adjusted steering clutches include:

• Uneven Turning: One track may engage more quickly than the other, causing the machine to turn unevenly.
  
• Slipping Tracks: A clutch that’s not adjusted properly may fail to fully engage, causing the tracks to slip under load.
  
• Increased Wear: Incorrect adjustments can cause excessive friction on the clutch plates, leading to premature wear and the need for more frequent repairs.
  

To prevent these issues, it’s important to regularly check and adjust the steering clutches to maintain optimal performance.
How to Adjust the Steering Clutch on a John Deere 420 Crawler
Adjusting the steering clutch on a John Deere 420 involves several steps to ensure that the clutch plates engage and disengage properly. This process requires precision and patience, but it’s essential for maintaining the machine’s steering capabilities.
Step 1: Preparation
Before beginning the adjustment, make sure the machine is on level ground and that the engine is off. Ensure that the tractor is in neutral, and the parking brake is engaged for safety. Having the correct tools on hand, including a wrench and screwdriver, will make the process easier.
Step 2: Inspect the Clutch Assembly
Start by inspecting the clutch assembly for signs of wear or damage. Check the clutch plates, springs, and seals for any visible issues. If any parts are worn or damaged, they should be replaced before proceeding with the adjustment.
Step 3: Locate the Adjustment Mechanism
On the John Deere 420, the clutch adjustment mechanism is typically located near the steering clutch lever. The mechanism usually consists of an adjusting nut or bolt that controls the tension on the clutch springs. The exact location may vary slightly depending on the model, so consult the operator’s manual for specifics.
Step 4: Adjust the Clutch Tension
Using the appropriate tool, adjust the nut or bolt to increase or decrease the tension on the clutch springs. The goal is to achieve the correct amount of engagement pressure so that the clutch plates engage smoothly but don’t cause excessive friction. If the adjustment is too loose, the clutch may slip; if it’s too tight, the clutch may not fully disengage.
Step 5: Test the Adjustment
After making the adjustments, test the machine by engaging and disengaging the clutches. You should notice smoother and more responsive steering. Pay close attention to any uneven turning or slippage, and make further adjustments as needed.
Step 6: Final Check
Once you’ve achieved the desired clutch engagement, tighten the adjustment nuts and secure any loose components. Double-check the entire clutch assembly to ensure that everything is in place and functioning properly.
Common Issues and Solutions
Here are a few common issues that may arise during the steering clutch adjustment process, along with solutions:

1. Uneven Clutch Engagement: If one track engages faster than the other, it may be due to a misaligned clutch or an issue with the linkage. Check the linkage for proper adjustment and alignment.
   
2. Slipping Tracks: Slipping can occur if the clutch plates aren’t properly engaging due to worn-out springs or dirty components. Cleaning the components and replacing worn springs can resolve this issue.
   
3. Overtightened Clutch: If the clutch is too tight, it can cause excessive wear on the plates and increase fuel consumption. If this happens, loosen the clutch slightly to allow for smoother operation.
   
4. Noisy Clutch: A noisy clutch may indicate that the clutch plates are worn or damaged. In this case, the plates should be replaced to restore smooth operation.
   

Maintaining the Steering Clutch System
To prevent the need for frequent adjustments, regular maintenance of the steering clutch system is key. Here are some maintenance tips:

1. Regular Inspections: Inspect the steering clutch system periodically for wear and tear. Look for any signs of oil leakage, rust, or debris that could interfere with clutch function.
   
2. Lubrication: Keep the clutch assembly well-lubricated to reduce friction and prevent premature wear. Use the recommended type of lubricant as specified in the operator’s manual.
   
3. Cleanliness: Dirt and debris can quickly damage the clutch plates and bearings. Keep the clutch area clean, especially when working in muddy or dusty environments.
   
4. Replace Worn Parts Promptly: As with any mechanical system, replacing worn-out parts before they fail will prevent larger issues from arising. Regularly check the clutch springs, bearings, and seals, and replace them as needed.
   

Conclusion
The John Deere 420 Crawler’s steering clutch system is a critical component that ensures smooth, reliable operation. Regular adjustment and maintenance are essential to keeping the machine in top condition, allowing for precise maneuvering on various job sites. By following proper procedures for adjusting and maintaining the steering clutch, operators can prevent costly repairs and extend the lifespan of their equipment.
When dealing with older models like the 1950s John Deere 420, it’s important to keep in mind that parts may be harder to find, and the machine may require more frequent attention to keep it running smoothly. However, with proper care and maintenance, the John Deere 420 Crawler remains a capable and durable machine, suited to a wide range of heavy-duty tasks.