The Bobcat 321 is a small compact excavator, good for tight jobs around houses, farms, and light utility work. The service manual is what a shop or field tech grabs when the machine quits behaving and you need more than guesswork. People use it when they're chasing hydraulic issues, engine problems, or electrical gremlins and need the same level of detail you'd expect in a Cat or Deere shop manual.
What this manual helps you do
- Diagnose hydraulic problems, trace lines, and check pressures on the boom, arm, bucket, and blade circuits
- Troubleshoot the hydrostatic drive, follow test procedures, and verify charge and drive performance
- Rebuild and reseal cylinders, swing components, and related hydraulic hardware with proper teardown and assembly steps
- Check and adjust engine systems, including fuel, cooling, and basic electrical so the diesel starts and runs right
- Trace and repair wiring issues using readable schematics so you're not guessing at connectors and splices
Who this is for
This is for anyone working on a Bobcat 321 in the serial range A76511001 to A76599999: small contractors, owner-operators, rental fleets, and shop mechanics. If you only want basic controls, capacities, or safety info, you need the operator's handbook instead, not this manual.
FAQ
Q: Is this a searchable PDF, and can I read the wiring diagrams clearly?
A: These manuals are usually supplied as searchable PDFs, and the wiring diagrams are designed to stay readable when you zoom in.
Q: Does this cover my exact 321 machine?
A: It's aimed at 321 excavators with serial numbers from A76511001 to A76599999. If your plate is outside that range, this may not match perfectly.
Q: Is this the right document for full repairs?
A: Yes, this is the workshop-level service manual, meant for real repair work, not just basic operation or parts lookups.
Bottom line: If your 321's serial tag falls in that A76511001-A76599999 window and you're actually wrenching on it, this is the manual you want.
📘 Show Index
Table of Contents:
- ALPHABETICAL INDEX
- CONTENTS
- FOREWORD
- SAFETY INSTRUCTIONS
- FIRE PREVENTION
- Maintenance
- Operation
- Electrical
- Hydraulic System
- Fueling
- Starting
- Spark Arrestor Exhaust System
- Welding And Grinding
- Fire Extinguishers
- SERIAL NUMBER LOCATIONS
- Excavator Serial Number
- Engine Serial Number
- DELIVERY REPORT
- BOBCAT EXCAVATOR IDENTIFICATION
- SAFETY AND MAINTENANCE
- LIFTING AND BLOCKING THE EXCAVATOR
- UPPERSTRUCTURE SLEW LOCK
- LIFTING THE EXCAVATOR
- OPERATOR CAB (ROPS / TOPS) (If Equipped)
- Emergency Exits
- Cab Door
- Front Window
- Front Window Wiper
- Window Washer Reservoir
- Right Side Windows
- TRANSPORTING THE EXCAVATOR
- TAILGATE
- Opening And Closing The Tailgate
- Adjusting the Bumper
- Adjusting The Tailgate Catch
- SERVICE SCHEDULE
- AIR CLEANER SERVICE
- Daily Check
- Replacing The Filters
- CAB FILTER
- ENGINE COOLING SYSTEM
- Cleaning The Cooling System
- Checking The Coolant Level
- Replacing The Coolant
- FUEL SYSTEM
- Fuel Specifications
- Filling The Fuel Tank
- Removing Water From The Fuel Filter
- Replacing The Fuel Filter
- Draining The Fuel Tank
- Removing Air From The Fuel System
- ENGINE LUBRICATION SYSTEM
- Checking Engine Oil
- Replacing Oil And Filter
- HYDRAULIC SYSTEM
- Checking And Adding Hydraulic Oil
- Diagnostic Connectors
- Replacing The Hydraulic Filter
- Replacing Hydraulic Oil
- LUBRICATION OF THE HYDRAULIC EXCAVATOR
- Rear Door Hinges
- Blade
- Boom Swing And Boom Base
- Boom, Middle
- Boom And Arm
- Frame Fittings
- Track Expansion Tube
- TRAVEL MOTOR
- Checking Oil Level
- Draining The Drive Motor
- SPARK ARRESTER MUFFLER
- ALTERNATOR BELT
- Adjusting The Alternator Belt
- SEAT BELT
- Inspection And Maintenance
- CONTROL CONSOLE LOCKOUTS
- Inspection And Maintenance
- DE-AERATION
- HYDRAULIC SYSTEM
- HYDRAULIC SCHEMATIC
- HYDRAULIC SYSTEM INFORMATION
- Glossary Of Hydraulic / Hydrostatic Symbols
- Troubleshooting The Hydraulic Circuit
- Troubleshooting The Cylinder Circuit
- Troubleshooting The Swing (Upperstructure Slew) Circuit
- Troubleshooting The Travel Circuit
- BOOM CYLINDER
- Testing
- Removal and Installation
- Parts Identification
- Disassembly
- Assembly
- ARM CYLINDER
- Testing
- Removal and Installation
- Parts Identification
- Disassembly
- Assembly
- BOOM SWING CYLINDER
- Testing
- Removal and Installation
- Parts Identification
- Disassembly
- Assembly
- BUCKET CYLINDER
- Testing
- Removal and Installation
- Parts Identification
- Disassembly
- Assembly
- BLADE CYLINDER
- Testing
- Removal and Installation
- Parts Identification
- Disassembly
- Assembly
- TRACK FRAME EXPANSION CYLINDER
- Testing
- Removal And Installation
- Parts Identification
- Disassembly
- Assembly
- MAIN RELIEF VALVE
- Testing And Adjusting The Main Relief Valve
- PORT RELIEF VALVES
- Testing And Adjusting The Port Relief Valve Pressure
- CROSSPORT RELIEF VALVES
- Testing And Adjusting The Crossport Relief Valve
- PRESSURE REDUCING VALVE
- Testing And Adjusting The Pressure Reducing Valve
- HYDRAULIC CONTROL VALVE
- Description
- Removal And Installation
- Parts Identification
- Disassembly
- Right Travel Valve Section Disassembly And Assembly
- Boom Swing Valve Section Disassembly And Assembly
- Arm Valve Section Disassembly and Assembly
- Bucket Valve Section Disassembly And Assembly
- Auxiliary Valve Section Disassembly And Assembly
- Boom Valve Section Disassembly And Assembly
- Left Travel Valve Section Disassembly And Assembly
- Swing (Slew) Valve Section Disassembly And Assembly
- Blade Valve Section Disassembly And Assembly
- Assembly
- HYDRAULIC PUMP
- Description
- Torque Adjustment
- Testing The Piston Pump
- Testing The Gear Pump
- Testing Auxiliary Hydraulic Flow
- Removal And Installation
- Parts Identification
- Disassembly
- Gear Pump Disassembly
- Piston Pump Disassembly
- Piston Pump Assembly
- Gear Pump Assembly
- Assembly
- MANIFOLD ASSEMBLY / ACCUMULATOR
- Description
- Removal And Installation
- Parts Identification
- Disassembly
- Assembly
- ACCUMULATORS
- TRAVEL MOTOR
- Description
- Removal And Installation
- Parts Identification
- Disassembly
- Assembly
- SWIVEL JOINT
- Description
- Removal And Installation
- Parts Identification
- Disassembly
- Assembly
- SWING MOTOR
- Description
- Removal And Installation
- Parts Identification
- Disassembly
- Assembly
- RIGHT CONTROL LEVER (JOYSTICK)
- Description
- Testing
- Handle Removal And Installation
- Removal And Installation
- Parts Identification
- Disassembly
- Assembly
- LEFT CONTROL LEVER (JOYSTICK)
- Description
- Testing
- Handle Removal And Installation
- Removal And Installation
- Parts Identification
- Disassembly
- Assembly
- HYDRAULIC FILTER MOUNT
- Description
- Removal And Installation
- HYDRAULIC RESERVOIR
- Description
- Removal And Installation
- OIL COOLER
- Description
- Removal And Installation
- BLADE / TRACK EXPANSION SOLENOID BLOCK
- Description
- Block Removal and Installation
- Solenoid Removal and Installation
- Block Disassembly And Assembly
- SLEW LOCK VALVE (FOR S/N A76511001 & ABOVE, A01711001 & ABOVE)
- Description
- Removal And Installation
- Parts Identification
- Disassembly And Assembly
- UNDERCARRIAGE
- BLADE
- Description
- Extension Removal And Installation
- Blade Removal And Installation
- TRACKS
- Track Lug Height
- Track Tension Adjustment
- Removal And Installation
- TRACK FRAME
- Disassembly And Assembly
- Removal And Installation Of Expandable Track Frame
- TRACK DAMAGE IDENTIFICATION
- Cutting Of The Steel Cords
- Causes Of The Damage
- Abrasion Of Embedded Metals
- Separation Of Embedded Metals
- Separation Of Embedded Metals Due To Corrosion
- Cuts On The Lug Side Rubber
- Cracks On The Lug Side Rubber Due To Fatigue
- Lug Abrasion
- Cracks And Cuts On The Lug Side Rubber
- Abrasion Of The Track Roller Side
- Cuts On The Edges Of The Track Roller Side
- TRACK IDLER
- Parts Identification
- Disassembly
- Assembly
- TRACK ROLLER
- Parts Identification
- Disassembly
- Assembly
- SWING CIRCLE GEAR
- UPPERSTRUCTURE AND SWING SECTION
- UPPERSTRUCTURE
- Description
- Removal
- Installation
- ROPS CANOPY
- CAB
- Removal And Installation
- Door Removal And Installation
- Front Window Removal And Installation
- Right Side Rear Sliding Window Removal And Installation
- Right Side Front Sliding Window Removal And Installation
- Glass Removal
- Right Side Front And Rear Sliding Window Weather Strip Removal And Installation
- Right Side Front And Rear Sliding Window Wiper Strip Removal And Installation
- Glass Installation
- SEAT AND SEAT MOUNT
- RIGHT CONSOLE
- Description
- Joystick Console Cover (Bottom) Removal And Installation
- Joystick Console Cover (Top) Removal And Installation
- Joystick Console Cover (Top) Disassembly And Assembly
- Compression Spring Removal And Installation (Canopy Only)
- Compression Spring Disassembly And Assembly (Canopy Only)
- Lever Removal And Installation (Canopy Only)
- Joystick Console Frame Removal And Installation
- Joystick Console Frame Disassembly And Assembly
- Right Rear Console Cover Removal And Installation
- Right Rear Console Cover Disassembly and Assembly
- Right Rear Console Frame Removal And Installation
- LEFT CONSOLE
- Description
- Joystick Console Cover (Bottom) Removal And Installation
- Joystick Console Cover (Top) Removal And Installation
- Compression Spring Removal And Installation
- Compression Spring Disassembly And Assembly
- Lever Removal And Installation
- Joystick Console Frame Removal And Installation
- Joystick Console Frame Disassembly And Assembly
- Left Rear Console Cover Removal And Installation
- Left Rear Console Frame Removal And Installation
- ENGINE SPEED CONTROL
- Removal and Installation
- Cable Removal and Installation
- BLADE CONTROL
- Removal and Installation
- Disassembly And Assembly
- Cable Removal and Installation
- UPPERSTRUCTURE SLEW LOCK
- Removal and Installation
- Disassembly And Assembly
- RIGHT PEDAL
- Removal And Installation
- Disassembly And Assembly
- TRAVEL CONTROLS
- Removal And Installation
- Disassembly And Assembly
- LEFT PEDAL
- Removal And Installation
- Disassembly And Assembly
- CONTROL LINKAGE ASSEMBLY
- Description
- Removal And Installation
- Right Half of Control Linkage Disassembly And Assembly
- Left Half of Control Linkage Disassembly And Assembly
- Bracket of Control Linkage Disassembly And Assembly
- FLOOR MAT AND FLOOR PANELS
- Description
- Removal and Installation
- FUEL TANK
- HORN
- SWING FRAME
- Description
- Removal And Installation
- Bushing Removal and Installation
- Swing Frame Bushing Removal
- Swing Frame Bushing Installation
- Boom Pivot Bushing Removal
- Boom Pivot Bushing Installation
- BOOM
- Description
- Removal And Installation
- Boom Bushing Removal And Installation
- ARM
- Description
- Removal And Installation
- Arm To Boom Bushing Removal And Installation
- Arm To Bucket And Bucket Link Bushing Removal And Installation
- BUCKET
- TAILGATE
- Removal And Installation
- Latch Removal And Installation
- ELECTRICAL SYSTEM AND ANALYSIS
- ELECTRICAL SCHEMATIC
- ELECTRICAL SYSTEM INFORMATION
- Glossary Of Electrical Symbols
- Troubleshooting
- Description
- Fuse And Relay Location / Identification
- Fuel Timer And Diode Location / Identification
- BATTERY
- Servicing
- Removal and Installation
- Using A Booster Battery (Jump Starting)
- ALTERNATOR
- Description
- Tests
- Alternator Output Test
- Full Field Test
- Alternator Regulator Test
- Alternator Regulator Test With Voltmeter
- Removal And Installation
- Belt Adjustment
- Charging System Inspection
- Parts Identification
- STARTER
- Removal And Installation
- Parts Identification
- Cleaning And Inspection
- LIGHTS
- UpperStructure Light Removal And Installation
- UpperStructure Light Disassembly and Assembly
- Boom Light Removal And Installation
- Boom Light Disassembly And Assembly
- Light Switch Removal And Installation
- MICROSWITCH
- Testing Left Console Microswitch
- Left Console Microswitch Removal And Installation
- Testing Right Console Microswitch
- Right Console Microswitch Removal And Installation
- TWO-SPEED BOOST SWITCH
- Description
- Removal And Installation
- FUEL LEVEL SENDER
- Removal And Installation
- Testing
- ENGINE SERVICE
- TROUBLESHOOTING
- SPARK ARRESTOR MUFFLER
- AIR CLEANER
- RADIATOR
- ENGINE COMPONENTS AND TESTING
- Valve Clearance Adjustment
- Engine Compression Checking
- Fuel Shutoff Solenoid – Checking
- Fuel Shutoff Solenoid Removal And Installation
- Fuel Shutoff Timer Removal And Installation
- Fuel Injection Pump Check
- Fuel Injection Pump Removal And Installation
- Fuel Injection Pump Timing
- Fuel Injector Removal And Installation
- Fuel Injector Checking
- Glow Plug Removal And Installation
- ENGINE
- Description
- Specifications
- Engine
- Fuel Injector Nozzles
- Fuel Injection Pump
- Cylinder Head
- Valves
- Valve Springs
- Rocker Arms
- Camshaft
- Cylinders
- Piston Rings
- Pistons
- Connecting Rods
- Crankshaft
- Oil Pump
- Thermostat
- Torque Values
- Engine Removal and Installation
- Engine Mount Replacement
- FLYWHEEL AND HOUSING
- Flywheel Housing Removal And Installation
- Hydraulic Pump Coupler Removal And Installation
- Flywheel Removal
- Flywheel Installation
- Rear End Plate Removal And Installation
- RECONDITIONING THE ENGINE
- Cylinder Head Removal And Installation
- Cylinder Head Disassembly And Assembly
- Cylinder Head, Servicing
- Cylinder Head Top Clearance
- Valve Guide, Checking
- Valve Timing, Checking
- Valve And Valve Seat Reconditioning
- Valve Seat Tightness
- Valve Spring
- Valve Tappets
- Rocker Arm And Shaft, Checking
- Timing Gearcase Cover Removal And Installation
- Idler Gear And Camshaft Removal And Installation
- Idler Gear and Shaft, Servicing
- Timing Gears Checking Backlash
- Fuel Camshaft Removal And Installation
- Fuel Camshaft Governor
- Crankshaft Gear Removal And Installation
- Oil Pan Removal And Installation
- Oil Pump Removal And Installation
- Oil Pump, Service
- Engine Oil Pressure, Checking
- Relief Valve
- Piston And Connecting Rod Removal And Installation
- Piston And Connecting Rod, Servicing
- Connecting Rod Alignment
- Crankshaft And Bearings Removal And Installation
- Crankshaft And Bearings, Servicing
- Cylinder Bore, Checking
- Water Pump Removal And Installation
- Water Pump Disassembly And Assembly
- Thermostat Removal And Installation
- Testing The Thermostat
- HEATER
- HEATER SYSTEM
- REGULATOR MAINTENANCE
- Filter Element Removal And Installation
- Heater Coil
- HEATER UNIT
- Removal And Installation
- Louver Removal and Installation
- Threaded Insert Removal And Installation
- HEATER COIL
- HEATER FAN
- HEATER VALVE
- SPECIFICATIONS
- SPECIFICATIONS 321 EXCAVATOR
- Machine dimensions
- Working range
- Lift Capacity (Object handling applications excluded)
- Performance
- Function Time
- Weights
- Controls
- Engine
- Electrical
- Hydraulic system
- Hydraulic cylinders
- Drive system
- Traction
- Brakes
- Slew system
- Serviceability
- Fluid capacities
- Fluid specifications
- Environmental
- Instrumentation
- Safety
- Standard features
- Options
- Attachments
- Bucket
- SPECIFICATIONS 323 EXCAVATOR
- Machine dimensions
- Working range
- Lift Capacity (Object handling applications excluded)
- Performance
- Function time
- Weights
- Controls
- Engine
- Electrical
- Hydraulic system
- Hydraulic cylinders
- Drive system
- Traction
- Brakes
- Slew system
- Serviceability
- Fluid capacities
- Fluid specifications
- Environmental
- Instrumentation
- Safety
- Standard features
- Options
- Attachments
- Buckets
- TORQUE SPECIFICATIONS FOR BOLTS
- Torque For General SAE Bolts
- Torque For General Metric Bolts
- HYDRAULIC CONNECTION SPECIFICATIONS
- O-ring Face Seal Connection
- Straight Thread O-ring Fitting
- Tubelines And Hoses
- Flare Fitting
- Port Seal Fitting
- HYDRAULIC FLUID SPECIFICATIONS
- CONVERSIONS
- Decimal And Millimeter Equivalents
- U.S. To Metric Conversion Chart
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