Part of the Case Repair Manuals.
This is the complete factory repair manual for the Case 621B and 721B wheel loaders. It is organized into the standard Case service groups and covers the machine from the turbocharged diesel engines, the 6T-590 in the 621B and the 6T-830 in the 721B, with their specification details, cylinder head and valve train, cylinder block, lubrication and cooling systems, and turbocharger, through the fuel and electrical systems, the steering, the power train with the transmission and axles, the brakes, and the loader hydraulics, plus the chassis. It carries standard torque specifications, fluids and lubricants, stall tests, pressure checks, troubleshooting, and step-by-step removal and installation, with the engine and many other sections split by model so the procedures match your machine.
What's Inside This Case 621B, 721B Repair Manual
| System | Pages | Key Topics |
|---|---|---|
| General | Standard Torque Specifications, Fluids and Lubricants, Loctite Product Chart | |
| Engines | Engine and Radiator Removal and Installation per Model, Stall Tests, 6T-590 (621B) and 6T-830 (721B) Specification Details, Cylinder Head and Valve Train, Cylinder Block, Lubrication System, Cooling System, Turbocharger | |
| Fuel System | Fuel System and Filters, Injection Pump, Fuel Injectors, Fuel Tank | |
| Electrical | Electrical Specifications and Troubleshooting, Batteries, Starter, Alternator, Instrument Cluster, Wiring | |
| Steering | Steering Specifications Pressure Checks and Troubleshooting, Steering Control Valve, Steering Cylinders, Priority Valve, Center Pivot | |
| Power Train | Transmission Specifications Pressure Checks and Troubleshooting, Transmission, Front and Rear Axles, Drive Shafts, Wheels and Tires, Transmission Control Valve | |
| Brakes | Brake Specifications and Troubleshooting, Brake Components, Accumulators, Parking Brake | |
| Hydraulics | Hydraulic Specifications Troubleshooting and Pressure Checks, Cleaning the Hydraulic System, Hydraulic Pump, Loader Control Valve, Cylinders, Pilot and Ride Control | |
| Chassis | Loader, ROPS Cab, Air Conditioning, Operator Platform, Mounted Equipment |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| 621B | ||
| Engine (621B) | 6T-590 turbocharged diesel | |
| 721B | ||
| Engine (721B) | 6T-830 turbocharged diesel | |
| 621B, 721B | ||
| Transmission | Powershift with transmission control valve | |
| Steering | Center-pivot articulated with priority valve | |
| Specifications and Pressure Checks | Engine, transmission, steering, and hydraulic specifications with pressure checks per group | |
Case 621B, 721B Common Problems This Manual Covers
Transmission slips, is slow to engage, or loses drive
Use the Power Train group's transmission specifications, pressure checks, and troubleshooting. Measure the clutch and system pressures against spec and check the transmission control valve before removing the transmission, since a pressure or valve fault often mimics internal wear. The removal and service procedures follow if a rebuild is needed.
Manual Section: Power TrainLoader is slow, weak, or jerky
Start with the hydraulic specifications, troubleshooting, and pressure checks to confirm pump output and system pressure, then work the loader control valve and the cylinders. Check the pilot and ride control if the loader feels jerky, and clean the hydraulic system if contamination is suspected before condemning the pump.
Manual Section: HydraulicsLow power, black smoke, or a boost concern
Work the engine coverage for your model (6T-590 on the 621B or 6T-830 on the 721B): use the stall tests and specification details, check the fuel system and injectors, and inspect the turbocharger. Confirm the fuel and intake before condemning the turbo, since a fuel or intake fault often presents as a boost problem.
Manual Section: EnginesSteering heavy, slow, or wandering
Use the steering specifications, pressure checks, and troubleshooting, then check the priority valve and the steering control valve. Confirm the priority and relief pressures before replacing the control valve or the steering cylinders, since a priority or supply fault often presents as heavy steering on an articulated loader.
Manual Section: SteeringFrequently Asked Questions
Which engine does my loader have, and is it covered?
The 621B uses the 6T-590 turbocharged diesel and the 721B uses the larger 6T-830 turbocharged diesel. The Engines group covers each with its own specification details, cylinder head and valve train, cylinder block, lubrication and cooling systems, and turbocharger, so follow the section that matches your model.
Does the manual cover the transmission pressure checks and troubleshooting?
Yes. The Power Train group has the transmission specifications, pressure checks, and troubleshooting, along with the transmission and the transmission control valve. That lets you measure clutch and system pressures against spec before removing the transmission, since a pressure or valve fault often mimics internal wear.
The loader is slow or weak. What does the manual give me?
Start with the hydraulic specifications, troubleshooting, and pressure checks to confirm pump output and system pressure, then work the loader control valve and the cylinders. Confirm the pressures against spec before replacing the pump, since a relief or valve fault commonly causes slow or weak loader function.
The steering is heavy or slow. What should I check?
Use the steering specifications, pressure checks, and troubleshooting, then check the steering priority valve and control valve. On an articulated loader the priority valve must feed the steering circuit first, so confirm the priority and relief pressures before replacing the control valve or the steering cylinders.
Are the specifications split by model?
Yes. The engine coverage and many other sections are split between the 621B and the 721B, since the two loaders use different engines (6T-590 versus 6T-830) and have model-specific specifications. Match your model to the correct section so the procedures and specs are right.
How quickly can I access this Case 621B, 721B manual after buying?
You get a 1860-page searchable PDF (627 MB) that downloads instantly after checkout. Open it on your laptop, tablet, or phone, and bring it right to the shop floor.
Can I print specific sections of this Case 621B, 721B Repair Manual?
Zero restrictions. The PDF is DRM-free. Print whatever sections you need to take out to the shop. Standard letter or A4 paper works.
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