Case 850B Track Loader: A Timeless Workhorse of Power and Versatility

[MikePhua]

Machine Heritage and Technical Overview
The Case 850B, introduced between 1976 and 1981, is a robust mid-size crawler loader known for its durability and adaptability. Key specifications include:

• Engine: CASE A336BD diesel producing roughly 75 HP.
  
• Operating Weight: Approximately 15,778 lbs (around 7,157 kg).
  
• Transmission: Power‑Shift system offering multiple forward and reverse gearing options.
  
• Blade Capacity: Around 1.5 cubic yards, enabling substantial material movement.
  

Serial numbers ranged from 7076501 to just over 7,400,000, making it identifiable by year of manufacture—helpful for restoration or maintenance tracking.
Dimension and Structural Details
According to spec resources, the Case 850B measures:

• Length (base machine): 14 ft 1 in
  
• Width: 6 ft 6 in
  
• Height: 8 ft 6 in
  These may vary depending on attachments or configuration.
  

Hydraulics feed into a final‑drive system using spur and bull gears housed in a one-piece, line-bored case with internal seal guards—optimizing strength and serviceability.
Operation, Steering, and Control
Operators appreciated the 850B’s intuitive control layout: a Power‑Shift transmission offering high/low for each track, yielding up to four speeds, and enabling efficient turns using differential track speeds rather than brakes.
From seasoned users:

“The transmission is tough… power is to both tracks in turning… In mud, it will slowly make the turn.”

This steering logic also preserved brake life, since early models relied on mechanical brakes ill‑suited to frequent pivoting.
Maintenance Notes and Common Issues
Several recurring maintenance themes emerged among users:

• Transmission and drive systems are respected for durability—but watch for hydraulic leaks and final drive oil conditions.
  
• Pin and bushing wear on loader arms, blade pivots, and tracks is common; getting early maintenance helps regain tight movement.
  
• Leaking seals around the transmission or final drive area were regularly noted, underscoring the need for vigilance after long service.
  
• Older models with failed engines may suffer blow-by, rough cold starts, or excessive fuel additives—pointing to possible in-frame rebuild needs.
  

Anecdotes from the Field
One user shared a vivid picture of an 850 with a backhoe attachment—a clear testament to its multi‑function potential, especially useful for forestry or excavation tasks in rugged environments.
Another said:

“The machine has some age but still has life left in her… replace the top loader arms and tower pins first.”
This advice came from a practiced eye noting loader arm wear and advising procedural service strut use for added safety during maintenance.

Parts Availability and Documentation

• Spare and replacement components remain accessible, particularly for undercarriage items such as sprockets, rollers, track shoes, and more.
  
• For in-depth repairs or restorations, a comprehensive service manual (over 1,000 pages) exists—covering all 850B machines with detailed diagrams and service procedures.
  

Glossary of Technical Terms

• Power‑Shift Transmission: Gearbox that switches speed ranges under load via hydraulic control.
  
• Final Drive: The final gear reduction unit that feeds torque into tracks.
  
• Line‑Bored Case: A single machined housing ensuring precise alignment of gears.
  
• Blow‑By: Gaseous leakage past piston rings into the crankcase, often indicating wear.
  
• In‑Frame Overhaul: Engine service where the unit remains in place, streamlining rebuild processes.
  

Why the Case 850B Still Matters Today
Its enduring reputation comes from a rare blend of adaptability, simplicity, and strength. Built with accessible parts, intuitive operation, and a supportive user base, these loaders remain a cherished asset on farms, woods, and work sites. Whether for grading, digging with a backhoe, or basic land clearing, the 850B continues to prove—workhorse quality doesn’t fade with age.