Part of the Case Repair Manuals.
The 621B and 721B are Case's B-series wheel loaders, and when the electrics act up or the steering goes soft the machine stops earning. This is the real factory service manual, part 7-60064, 1,860 pages covering the engine (the 6T-590 on the 621B and the 6T-830 on the 721B), fuel, electrical, steering, power train, brakes, hydraulics and chassis. Whether you are chasing a fuse that keeps blowing, a worn cylinder sleeve, or a steering that will not hold, it is here in factory order with the wear limits and torque values to work to.
What's Inside This Case 621B, 721B Manual
| System | Pages | Key Topics |
|---|---|---|
| General | Machine and Engine Specifications, Standard Torque Values, Fluids and Lubricants, General Service | |
| Engines | 6T-590 (621B) and 6T-830 (721B) Turbo Diesel Repair, Cylinder Head, Block, Sleeves, Timing, Cooling | |
| Fuel System | Injection Pump, Injectors, Fuel Supply, Filters, Governor, Speed Settings | |
| Electrical | Wiring Diagrams, Charging and Starting, Lighting, Loader Control Circuit, Gauges | |
| Steering | Hydrostatic Steering, Steering Pump and Valve, Cylinders, Articulation | |
| Power Train | Transmission, Torque Converter, Axles, Differentials, Final Drives | |
| Brakes | Service and Park Brakes, Brake Valves, Accumulator, Bleeding and Adjustment | |
| Hydraulics | Loader Hydraulic Circuits, Pump, Control Valves, Lift and Tilt Cylinders, Reservoir | |
| Chassis | Frame and Articulation, Loader Linkage, Bucket, Counterweight, Cab |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| 621B | ||
| Engine | 6T-590 turbocharged diesel | |
| 721B | ||
| Engine | 6T-830 turbocharged diesel | |
| Both | ||
| Engine Support Bracket to Rear Frame Bolt Torque | 850 to 950 lb-ft (1152 to 1288 Nm) | |
| Fan to Pulley Cap Screw Torque | 504 lb-in (57 Nm) | |
| Cylinder Sleeve Taper Limit | 0.04 mm maximum | |
| Production Years | 1993 to 1998 | |
Case 621B, 721B Common Problems This Manual Covers
Fuse blows repeatedly from an electrical short
A fuse that keeps blowing is a shorted wire, most often in the loader joystick control circuit. Isolate the circuit, inspect the harness where it flexes at the joint for chafed insulation, and repair or replace the shorted lead before returning to work. The electrical section covers the wiring and the circuit tracing.
Manual Section: ElectricalCylinder sleeve taper or bore wear beyond limit
Sleeve taper past the 0.04 mm limit means the bore is worn or the sleeve is deformed. Measure the sleeve at several points, compare against the wear limit, and replace the sleeve and related parts as a set if it is out of spec. The engine section covers the measurement, the limits and the sleeve service.
Manual Section: EnginesSteering malfunction or loss of steering control
Loss of steering points to an internal steering component failure or a hydraulic pressure loss. Check the steering pump and relief pressure, bleed the system, and inspect the steering valve and cylinders for internal leakage before condemning a part. The steering section covers the pressures and the component service.
Manual Section: SteeringFrequently Asked Questions
What does Case part number 7-60064 cover?
It is the full factory service manual for the Case 621B and 721B wheel loaders, 1,860 pages covering the engine (6T-590 on the 621B, 6T-830 on the 721B), fuel, electrical, steering, power train, brakes, hydraulics and chassis.
My 621B keeps blowing a fuse, where do I look?
A fuse that blows repeatedly points to a shorted wire, often in the loader joystick control circuit. The electrical section covers the wiring, the control circuit and how to trace and isolate the short before you replace the fuse again.
What is the cylinder sleeve wear limit on these engines?
The cylinder sleeve taper limit is 0.04 mm. The engine section covers measuring the sleeve, the wear limits and the sleeve service, along with the related torque values.
My loader stops moving after a lift, is a transmission reset in here?
Yes. The power train section covers the transmission, the controls and the diagnostic and adjustment procedures for a transmission that drops out or will not engage after loader work.
Is this the same manual a Case dealer uses?
It is the factory service manual (part number 7-60064), the same step by step repair, specification and torque data the 621B and 721B were built and serviced to.
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