Model Spotlight

Case 850 Crawler Dozer: Specs, Parts & Common Issues

The original Case 850 Crawler Dozer is the mid-large frame entry in the Case crawler dozer family from the mid-1970s — Case A336BD inline six-cylinder diesel, mechanical or power shift transmission depending on year and option, and a chassis that sits between the smaller 750 and the larger 1150 in the original Case dozer lineup. Predecessor to the 850B (1976–1981), 850C (1981–1987), 850D (1980–1994), and the modern 850 G / H / K / L / M generations.

Broken Tractor Editorial Team• Updated May 2026• 10 min read

The Case 850 Crawler Dozer is the original mid-large frame Case crawler dozer, produced through the mid-1970s. The 850 sits between the Case 750 (mid-large frame, smaller) and the Case 1150 (large frame) in the Case construction dozer line of that era. The original 850 set the chassis pattern that the later 850B, 850C, and 850D refined before the substantially redesigned modern G / H / K / L / M generations arrived in the late 1980s and beyond.

The Case 850 family is one of the deepest in the modern Case dozer line The 850 model line spans roughly 50 years and a dozen sub-generations — the original 850 (mid-1970s), 850B (1976–1981), 850C (1981–1987), 850D (1980–1994), 850E (1987–1990), 850G, 850H (2000–2003), 850K (2004–2009), 850L (2009–2014), and 850M (2014–present). Each generation has distinct engines, drivetrains, hydraulics, and parts. When sourcing parts, confirm which 850 generation you're working on — parts that look interchangeable across the family often are not.

At-a-glance specifications

Case 850 (original) — factory specifications

Production era: Mid-1970s (original 850, pre-B suffix)
Successor: Case 850B (1976–1981)
Engine: Case A336BD inline 6-cylinder diesel
Displacement: 336 cu in (~5.5 L)
Power class: ~75 horsepower flywheel (configuration dependent)
Transmission: Mechanical or power shift (option / year dependent)
Hydraulics: Open-center implement circuit
Variants: Standard, LGP (Low Ground Pressure)
Operating weight: ~21,000 – 24,000 lb depending on configuration
Blade: 6-way bulldozer blade — angle and tilt blade options
Serial plate location: Right side of operator's platform / chassis frame

Where the original 850 sits in the 850 family

Case 850 (original) — mid-1970s, the machine documented in this spotlight. Case A336BD 6-cyl diesel, mechanical or power shift drivetrain.
Case 850B — 1976–1981. Refresh of the original with updated controls and accessory updates.
Case 850C — 1981–1987. Continued refinements; dozer and crawler loader variants offered.
Case 850D — 1980–1994. Long production run with major refinements over the C.
Case 850E — 1987–1990. E-generation refresh.
Case 850G — 1990s mid-generation refresh. Cummins-derived engines come into play.
Case 850H — 2000–2003. Hydrostatic dual-path drivetrain arrives.
Case 850K — 2004–2009. K-generation chassis and cab refresh.
Case 850L — 2009–2014. L-generation (Tier 3 emissions era).
Case 850M — 2014–present. Tier 4 Final / Stage V SCR + DEF aftertreatment.

Engine and powertrain

The original Case 850 used the Case A336BD inline six-cylinder diesel engine — 336 cubic inches of displacement (approximately 5.5 liters). The A336 series is the workhorse Case 6-cyl diesel of the 1970s, used across multiple Case industrial and agricultural applications of the era. Approximately 75 horsepower flywheel in 850-class trim.

Transmission options ranged from mechanical gear-driven setups in early production to power shift configurations on later units, depending on option package. Power shift made the 850 more responsive in dozing operations where direction changes are frequent.

Undercarriage

The 850-class undercarriage shares some component heritage with the 750 (mid-large frame) and 1150 (large frame) families. Sprocket bolt patterns, idler geometries, and master pin dimensions cross-fit on multiple components — confirm by part number against your serial. Roller and idler bushings are routine wear items at production-run age, and most field-service 850s have seen at least one full undercarriage rebuild.

Browse the Case Dozer Parts hub for current 850-era undercarriage availability.

Blade system and hydraulics

The 850 ships with a 6-way bulldozer blade — angle and tilt control hydraulically actuated. Blade cylinders, blade-carrier slider blocks, and cutting edges are all routine service items. Cutting edge replacement is generally needed every few hundred to few thousand hours of dozing depending on material and operator habit.

Hydraulic implement-circuit pressure is moderate by modern standards — open-center hydraulic systems were standard in this era. Seal kit availability for the blade cylinders is generally good, with aftermarket kits supporting most 850-era cylinder dimensions.

Common service items on the original 850

Engine accessory aging

Water pump, alternator, starter, and injection pump on the A336BD are routinely rebuilt or replaced over the engine's service life. Cooling system service (radiator core flush or replacement, fan belt, hose set) is a routine maintenance milestone on 40-plus-year-old machines.

Hydraulic seal failure

Blade cylinder seal failures are common at production-run age. Cylinder rod chrome corrosion and seal weep are typical symptoms. Seal kit rebuilds address most cases; severe rod corrosion requires rod replacement.

Undercarriage replacement cycles

Track chains, rollers, idlers, and sprockets all have measurable wear lives. Modern aftermarket undercarriage is available for the 850 family.

Operator station and ROPS

Cab and canopy hardware, seat cushion replacement, and floorboard wear are typical aging-machine issues. ROPS structural integrity should be verified before resale.

Wiring and electrical

40-year-old wiring harnesses are routinely brittle. Hard starts, intermittent gauges, and dim lights are often traced to harness corrosion or insulation failure rather than the underlying component.

Cross-fit notes for the original 850

Parts on the original 850 family can cross-fit with both the 750 family (smaller-class) on some master pins and roller dimensions, and the 1150 family (larger-class) on some idler bushings and blade-carrier hardware. The Case A336 engine block is shared with other Case industrial applications of the era — A336 accessory parts source from a broader pool than the dozer-specific catalog. Confirm by part number against your serial before ordering.

Parts and cross-fit components

Component area	What to look for	Notes
Sprockets & segments	Track sprocket assemblies, bolt-on segments	Some 850-era sprockets cross-fit the 750 and 1150 families on shared bolt patterns.
Idlers & rollers	Front idler assemblies, top and bottom roller sets	Idler and roller bushings see mid-large class crawler cross-fit.
Track recoil & adjusters	Recoil spring, adjuster yoke, chrome rod	Confirm by serial — running production changes apply.
Master pins	Track master pin and bushing	Master pins share geometry across mid-large Case dozers in the era.
Cutting edges & end bits	Standard and severe-duty cutting edges, end bits	Aftermarket cutting edges widely available.
Blade cylinder seal kits	Angle, tilt, lift cylinder seal kits	Confirm cylinder dimensions before ordering.
Engine accessory parts	Water pump, alternator, starter, fuel injection	Case A336BD accessories share parts with other Case industrial 6-cyl applications.
Radiators & cooling	Radiator cores, fan belts, hose sets	Aftermarket radiator and cooling cross-fit available.
Filter service kits	Engine oil, fuel, air, hydraulic filter sets	Filter kits packaged by application speed routine service.
Operator seat	Universal industrial seat with mount kit	Universal Case industrial seats fit the 850 operator station with standard mount kits.

For 850-era parts inventory and cross-fit confirmation, browse the Case Dozer Parts hub or contact our parts desk directly.

Working on a Case 850?

The original 850 is a 40-plus-year-old machine — year and serial dictate which parts fit. Our specialists can verify fitment by serial and walk you through the 850 family's cross-fit options.

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Why the original 850 is still in service

The 850 sits in a sweet spot for mid-large dozer work — bigger than a 750 for serious pushing power but smaller and easier to transport than a 1150 or 1450. For commercial dirt work, larger agricultural site prep, private road maintenance, and major land-clearing, an 850 in good mechanical condition remains a productive machine. The Case A336 six-cylinder diesel is a known, well-supported engine, and the mechanical and power shift drivetrains are simpler to troubleshoot in the field than the hydrostatic systems on the later 850H / K / L / M.

Broken Tractor Editorial Team

This spotlight was compiled from factory Case service literature for the original 850 production family, CNH parts catalogs, Case A336BD engine documentation, and the verified BigCommerce catalog at brokentractor.com. Serial-specific fitment is best confirmed by phone before ordering — the multi-decade production window of the 850 family means small changes between years.