Factory-level repair data for the Mustang 642 and 844 telehandler runs 341 pages here (OEM #913250), system by system: engine removal and installation, transmission, front and rear axles, steering control valve, hydraulic pump, and the full telescoping boom assembly. The hydraulic schematics include a separate PWP variant, and the wiring diagrams pair with troubleshooting charts for the starter, park brake, and steering mode circuits, plus fault trees for boom lift, frame leveling, and steering. Torque your 7/16-20 hydraulic tube fittings to 9-12 lb-ft (12-16 Nm); the spec table lists every thread size in the system. Skip the guesswork of chasing faults with a multimeter and a prayer. Bookmarked and keyword-searchable, the PDF opens on any device, so you can read it right at the machine and start the repair.
What's Inside This Mustang 642, 844 Manual
| System | Pages | Key Topics |
|---|---|---|
| Personal Safety Information and Decal Locations | 5 | Safety, Safety Rules and Reminders, Modifications, Nameplates, Markings and Load Capacities, Roll Over Protective Structure, Protect the Environment |
| General Information and Specifications | 17 | Sae Fastener Torque Chart, Metric Fastener Torque Chart, Standard Torque Data for Hydraulic Tubes and Fittings, Indicator and Operation Symbols, Fluid Capacities and Types |
| Engine | 33-56 | Engine Removal, Engine Installation, Special Torque Values, Relieving Hydraulic Pressure |
| Electrical Schematics, Troubleshooting Testing & Adjustment Procedures | 57-80 | Instrument Panel or Panel Bulb Replacement, Electrical Schematics |
| Battery Removal and Installation | 81-88 | Battery Removal, Battery Installation |
| Steering Control Valve Removal and Installation | 89-96 | Control Valve Installation, Steering Control Valve Installation |
| Transmission | 97-112 | Transmission Removal, Transmission Installation, Specifications |
| Rear Axle Removal and Installation | 113-124 | Rear Axle Removal, Rear Axle Installation, Relieving Hydraulic Pressure |
| Front Axle Removal and Installation | 125-136 | Front Axle Removal, Front Axle Installation, Relieving Hydraulic Pressure |
| Hydraulic Schematics, Troubleshooting Testing & Adjustment Procedures | 137-184 | Hydraulic Schematics, Testing & Adjustment Procedures (Introduction), Hydraulic Specifications, Schematics (Hydraulic Schematics, Hydraulic Schematics with Pwp) |
| Hydraulic Pump | 185-192 | Pump Removal, Pump Installation |
| Frame Leveling Cylinder Removal & Installation | 193 | Frame Leveling Cylinder Removal, Frame Leveling Cylinder Installation, Relieving Hydraulic Pressure |
| Tilt Cylinder Removal & Installation | 201-208 | Tilt Cylinder Removal, Tilt Cylinder Installation, Relieving Hydraulic Pressure |
| Hydraulic Cylinder Repair | 209-220 | Cylinder Disassembly, Cylinder Assembly, General Information |
| Stabilizer Cylinder Removal and Installation | 221-228 | Stabilizer Cylinder Removal, Stabilizer Cylinder Installation, General Information, Relieving Hydraulic Pressure |
| Stabilizer Cylinder Repair | 229-240 | Stabilizer Cylinder Disassembly, Stabilizer Cylinder Assembly, General Information |
| Slave Cylinder Removal & Installation | 241-248 | Slave Cylinder Removal, Slave Cylinder Installation |
| Lift Cylinder | 249-264 | Lift Cylinder Removal, Lift Cylinder Installation, Lift Cylinder Adjustment, Check Lift Cylinder Adjustment, Lift Cylinder Eccentric Pin Adjustment |
| Boom Extend Cylinder Removal & Installation | 265-272 | Extend Cylinder Removal, Extend Cylinder Installation, Relieving Hydraulic Pressure |
| Boom Assembly Removal and Installation | 273-284 | Boom Assembly Removal, Boom Assembly Installation, General Information |
| Single and Double Leaf Chain Adjustment | 285-288 | Leaf Chain Adjustment, Leaf Chain Maintenance, General Information |
| Inner Boom Section Removal and Installation | 289-300 | Relieving Hydraulic Pressure for the Tilt Cylinder and Boom Extend Cylinder, Inner Boom Removal, Inner Boom Installation |
| Telescoping Boom Double Chain and | 301-308 | Double Chain Roller Bearing Removal, Double Chain Roller Bearing Installation |
| Telescoping Boom Single Chain and | 309-316 | Removal, Installation, Single Chain Roller Bearing Replacement |
| Intermediate Boom Section Removal and Installation | 317-324 | Intermediate Boom Removal, Intermediate Boom Installation, General Information |
| Hood and Cover Removal and Installation | 325-341 | Front Hood Removal, Front Hood Installation, Rear Hood Removal, Rear Hood Installation, Radiator Cover Removal |
Every system also includes mandatory safety shutdown procedure.
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Wheel Nut Torque | 450 ft.-lbs. (610 Nm) | p. 119 |
| Recommended Tire Type | 13.00 x 24 G2 12-ply | p. 26 |
| Hydraulic Tube and Fitting Torque (Thread Size 7/16-20) | 9 to 12 lb-ft (12 to 16 Nm) | p. 20 |
| Hydraulic Tube and Fitting Torque (Thread Size 1/2-20) | 12 to 15 lb-ft (16 to 20 Nm) | p. 20 |
| Seal Replacement | Install new seals (no specific numerical value) | p. 215 |
| Hydraulic Filter Type | Remote, 10 Micron, Replaceable Element | p. 24 |
| Hydraulic Filter Rated Flow | 100 GPM (371 L/min) | p. 24 |
| Battery Type | One - 950 CCA Low-Maintenance Type, Group Size 4 DLT | p. 25 |
| Battery Terminal Tightness | Clean and tight (no specific numerical torque value) | p. 86 |
| Engine Crankcase Capacity (4045T John Deere) | 14.0 qts (13.3 L) | p. 22 |
| Hydraulic System Reservoir Capacity | 47.0 gal (178 L) | p. 22 |
| Main Control Valve Relief Pressure | 3000 PSI (207 bar) | p. 24 |
Mustang 642, 844 Common Problems This Manual Covers
Mustang 642/844 telehandler boom lifts slowly or won't reach full height under load p. 137
Check hydraulic fluid level first; the reservoir holds 47.0 gal (178 L). If level is good, run the hydraulic troubleshooting procedures beginning at page 137 to isolate whether the fault is in the lift circuit, pump output, or main control valve. Relief pressure at the main control valve should measure 3000 PSI (207 bar) during a full system pressure test.
Manual Section: Hydraulic Schematics, Troubleshooting Testing & Adjustment ProceduresEngine cranks slowly or won't fire, starter engagement weak in cold conditions p. 59
Verify the battery meets the 950 CCA specification and inspect the terminals for corrosion. Work through the starter circuit troubleshooting procedures at page 59, testing fuses, relays, and key switch in sequence before pulling any wiring. If the starter engages but the engine won't fire, move to the fuel system and check coolant level using the engine service procedures at page 35.
Manual Section: Electrical Schematics, Troubleshooting Testing & Adjustment ProceduresPark brake won't release after shutdown, machine drags or refuses to drive p. 61
Test the park brake fuse and relay first, then verify pilot pressure to the brake release circuit using the hydraulic troubleshooting procedures at page 137. System pressure must reach 3000 PSI (207 bar) at the main relief valve; low pilot pressure holds the brake applied even with the switch released. Trace brake control wiring through the electrical troubleshooting section at page 61.
Manual Section: Electrical Schematics, Troubleshooting Testing & Adjustment ProceduresBoom extends unevenly or stutters, visible slack in telescoping chains p. 285
Inspect both leaf chains for wear and lubrication using the procedures at page 285; a dry or stretched chain is the first place to look when extension is uneven or jerky. Adjust chain tension following the procedure in that same section. If the extension cylinder travel is also inconsistent, check the lift cylinder eccentric pin adjustment covered at page 249 to correct cylinder length differences.
Manual Section: Single and Double Leaf Chain AdjustmentElectrical controls cut out intermittently, instrument panel lights flicker or go dark p. 81
Remove the battery per page 81 and clean both terminals until bright metal shows on both the cable end and the post. Reinstall and verify connections are clean and tight per page 86. A 950 CCA battery that passes a static voltage check can still fail under starter load, so test under load before assuming a wiring fault. Trace persistent issues through the wiring diagram at page 65.
Manual Section: Battery Removal and InstallationHydraulic hose fittings weeping fluid, wet spots on cylinders and connections p. 209
Identify the leak source before tightening anything. Torque the suspect fitting to spec per page 20: a 3/4-18 thread hydraulic tube nut takes 35-40 lb-ft (47-54 Nm). Replace cracked hoses rather than retorquing them, then top the reservoir back to 47.0 gal (178 L). If the leak is at a cylinder rod seal, rebuild with new seals using the cylinder repair procedures at page 209.
Manual Section: Hydraulic Cylinder RepairFrequently Asked Questions
What are the torque specs for Mustang 642 wheel nuts?
On the Mustang 642 telehandler, the front and rear axle wheel nuts get a final torque of 450 ft.-lbs. (610 Nm). Hit that value for a safe, secure wheel mount.
Mustang 642 torque specs wheel nuts
Tighten the Mustang 642 wheel nuts to 450 ft.-lbs. (610 Nm) on both the front and rear axles. That figure matters for keeping the wheels mounted securely.
What are the replacement specifications for tires?
Mustang lists 13.00 x 24 G2 12-ply as the recommended tire for the telehandler. Matching that size keeps the machine compatible and performing as designed.
What do I get after purchasing this Mustang 642, 844 manual?
Checkout delivers a 341-page searchable PDF, downloadable right away. Open it on a laptop, tablet, or phone and take it straight to the shop floor.
Are there any print restrictions on this Mustang 642, 844 manual?
Yes. The PDF carries no DRM, so print any page or section you need for the shop. It works with any standard printer.
Can I find hydraulic circuit diagrams in this Mustang 642, 844 manual?
Yes. Full hydraulic schematics are included, with flow diagrams, valve configurations, and pressure specifications.
Document Quality
This document is a scanned PDF with an optical character recognition (OCR) layer, allowing you to search and copy the full text. The text is generally crisp and easy to read, though it exhibits the slight fuzziness typical of scanned materials rather than native digital sharpness. Diagrams and illustrations primarily consist of clear raster photos with legible labels, while charts and electrical schematics are also raster images that remain readable but show pixelation when zoomed. All pages are clean and free from scan artifacts, stains, or skewed content. You will find several blank pages throughout the document, typically at the end of sections.
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