Bobcat 843 Left Pedal Linkage Wear and Float Function Restoration

[MikePhua]

The 843 and Bobcat’s Skid Steer Evolution
The Bobcat 843 skid steer loader was introduced in the mid-1980s as part of Bobcat’s 40-series lineup, designed to offer increased lift capacity and hydraulic performance for contractors, landscapers, and agricultural users. With a rated operating capacity of approximately 1,700 lbs and a 54-horsepower diesel engine, the 843 became a popular mid-frame machine known for its mechanical simplicity and rugged build.
Bobcat, founded in North Dakota in 1947, pioneered the compact loader concept and has sold millions of units globally. The 843 was a transitional model, bridging older mechanical systems with more refined hydraulic controls. Its foot pedal-operated boom and bucket system allowed intuitive control, but over time, wear in the linkage and pivot assemblies can degrade performance—especially in functions like float mode.
Understanding the Left Pedal Linkage and Float Mechanism
The left pedal on the Bobcat 843 controls the boom lift and lower functions. When pressed fully forward, it engages the float position, allowing the boom to descend under its own weight and follow ground contours without hydraulic resistance. This is essential for grading, snow removal, and surface cleanup.
Key components involved:

• Left foot pedal
  
• Cross lever (pivoting linkage between pedal and valve spool)
  
• Pivot bearing (supports cross lever movement)
  
• Valve block (controls hydraulic flow to boom cylinders)
  
• Detent balls and springs (hold float position mechanically)
  

Over time, the pivot bearing (often referenced as item 17 in parts diagrams) can develop excessive play, preventing full engagement of the float detent. This results in the boom lowering but not entering true float mode, reducing grading precision and increasing operator fatigue.
In one fleet in Alberta, a contractor noticed that his 843’s boom would lower but resist floating. After inspecting the linkage, he found the pivot bearing had worn into an oval shape, causing misalignment with the valve spool.
Symptoms of Linkage Wear and Float Failure
Operators may observe:

• Boom lowers but does not float
  
• Pedal feels soft or spongy at full depression
  
• Audible click from detent missing or inconsistent
  
• Increased resistance when trying to engage float
  
• Hydraulic valve block recently serviced but issue persists
  

In one rebuild in Texas, a technician replaced all detent balls and springs but still couldn’t achieve float. The root cause was excessive play in the cross lever pivot, which had worn beyond tolerance and was no longer transferring full pedal motion.
Accessing the Pivot Bearing and Linkage Assembly
Servicing the pivot bearing requires partial disassembly of the loader’s control linkage. Challenges include:

• Limited visibility due to chain case and hydrostatic motor proximity
  
• Bolt head may be located inside the chain case
  
• Removal of hydraulic pumps or reduction box may be necessary for full access
  
• Use of mirrors and flexible tools may help during inspection
  

Recommended steps:

• Disconnect battery and relieve hydraulic pressure
  
• Remove seat and floor panels for access
  
• Inspect linkage with mirrors or borescope
  
• If bearing is worn, plan for partial drivetrain disassembly
  
• Replace bearing with OEM or precision-machined equivalent
  
• Reassemble and test pedal travel and float engagement
  

In one rebuild in Maine, a technician fabricated a custom bearing sleeve from bronze alloy to restore pivot alignment. The loader regained full float function and improved grading performance.
Preventive Maintenance and Linkage Longevity
To extend the life of the pedal linkage:

• Grease pivot points monthly
  
• Inspect pedal travel and detent engagement quarterly
  
• Replace worn bushings and bearings before excessive play develops
  
• Use high-quality seals and springs during valve block service
  
• Avoid forcing pedal into float—use smooth, deliberate motion
  

Recommended upgrades:

• Install pedal travel limiter to prevent overextension
  
• Use stainless detent balls and springs for corrosion resistance
  
• Add inspection port or removable panel for easier access
  

In one municipal fleet in France, adding a pedal limiter reduced bearing wear and improved operator consistency. The loader was used for snow removal and sidewalk cleanup, where float mode was critical.
Conclusion
The Bobcat 843’s left pedal linkage plays a vital role in boom control and float functionality. When pivot bearings wear or misalign, float mode becomes unreliable, impacting grading and surface work. With careful inspection, targeted repairs, and preventive upgrades, operators can restore full hydraulic responsiveness and extend the life of this classic skid steer. Whether clearing snow or leveling gravel, the 843 proves that mechanical precision still matters.