Repairing a Cracked Stick on the John Deere 310E Backhoe

[MikePhua]

The John Deere 310E and Its Structural Design
The John Deere 310E backhoe loader was introduced in the early 1990s as part of Deere’s evolution in compact construction equipment. With a four-cylinder diesel engine producing around 70 horsepower and a robust extendable dipper stick, the 310E was designed for trenching, loading, and utility work. Its popularity stemmed from a balance of power, maneuverability, and serviceability, making it a staple in municipal fleets and private contracting operations.
The extend-a-hoe configuration added reach and flexibility, but also introduced stress points near the upper stick pin—especially under repetitive loading or side pressure. Over time, fatigue cracks can develop in this area, particularly if previous repairs were improperly executed or if the machine was subjected to high-impact tasks like stump removal or rock prying.
Terminology Annotation
- Stick (Dipper Arm): The hydraulic arm between the boom and bucket, responsible for reach and digging depth.
- Extend-a-Hoe: A telescoping stick design that increases reach without repositioning the machine.
- V-Notch Weld Prep: A technique where the crack is ground into a V-shape to allow full penetration welds.
- 7018 Electrode: A low-hydrogen welding rod known for strong, ductile welds and good crack resistance.
- Rosebud Torch: A wide-flame oxy-acetylene torch used for preheating metal before welding to reduce thermal shock.
Assessing the Damage and Previous Repairs
In one case, a 310E exhibited a crack near the top of the stick, close to the pin boss. The machine had previously been repaired with ⅜-inch steel plates welded to the top and bottom of the stick, but the sides were left unreinforced. The crack reappeared along one of the old welds, suggesting that the initial repair lacked full penetration and failed to address internal stress propagation.
Before welding, it’s critical to inspect the entire stick for hidden fractures. Dye penetrant testing or magnetic particle inspection can reveal subsurface cracks that may not be visible. If the stick has been plated previously, those plates should be removed or cut back to expose the original metal and allow proper weld prep.
Recommended Welding Procedure
To restore structural integrity:

• Remove any surface plates or weld overlays near the crack
  
• Grind the crack into a deep V-notch to expose clean metal
  
• Preheat the area with a rosebud torch to around 300°F to reduce thermal shock
  
• Use 7018 electrodes for the root pass, ensuring full penetration
  
• Grind out the opposite side of the crack and repeat the weld process
  
• Clean slag between passes and finish with a cap weld that blends smoothly into the parent metal
  
• Allow the weld to cool slowly, ideally under insulation or in ambient air without forced cooling
  

Post-weld stress relief can be achieved by reheating the area slightly and allowing it to cool gradually. This reduces the risk of hardening and future cracking.
To Brace or Not to Brace
While adding reinforcement plates may seem like a good idea, they can introduce new stress concentrations if not properly designed. If the weld is executed correctly and the stick is not used beyond its rated capacity, bracing may be unnecessary. However, in high-cycle environments or machines used for demolition, gussets or side plates can help distribute load more evenly.
If bracing is added:

• Use curved or tapered plates to avoid sharp corners
  
• Weld only on low-stress zones, avoiding full perimeter welds that trap stress
  
• Match plate thickness to the stick wall to prevent uneven flexing
  
• Avoid welding across the pin boss or hydraulic cylinder mounts
  

Field Anecdotes and Practical Advice
A technician in Missouri shared that he repaired a cracked stick on a 310E using the V-notch and 7018 method. The machine returned to service and operated for over 1,000 hours without recurrence. He emphasized the importance of preheating and slow cooling, noting that a rushed weld in cold weather had previously failed within weeks.
Another operator in Alberta used bracing plates but later removed them after noticing stress cracks forming at the weld toes. He re-welded the stick using full penetration passes and reported better long-term results.
Preventative Measures and Operator Habits
To reduce the likelihood of stick cracking:

• Avoid side loading the bucket during prying operations
  
• Use proper bucket sizes and avoid overextension of the dipper
  
• Inspect welds and pin bosses during routine maintenance
  
• Keep hydraulic pressures within factory specs to prevent overloading
  
• Train operators to recognize signs of fatigue, such as unusual flex or audible creaking
  

Documentation of repairs, including weld type, electrode batch, and preheat temperature, can help future technicians assess the integrity of the repair.
Conclusion
Repairing a cracked stick on a John Deere 310E requires more than just welding—it demands a methodical approach rooted in metallurgy, stress analysis, and field experience. With proper weld prep, material handling, and post-weld care, the stick can be restored to full function without compromising safety. In the world of heavy equipment, a strong weld isn’t just metal—it’s trust, forged one pass at a time.