Running a 1988-1991 Mustang 960 and need the factory numbers? OEM #000-12909 pulls the 930, 940, 960, 920E, 930A, and 940E into one 134-page reference. Hydraulic schematics trace every circuit through the hydrostatic drive and lift systems; wiring diagrams are split between the 960 and the 930/940; E-Series interlock diagrams cover solenoid spool locks and fuel lever control. Troubleshooting runs 12 pages across steering, hydraulics, chain case, engine, and electrical, with 3 pages of standard and metric torque specs behind it. Set drive chain deflection to 1/8 inch (3.2 mm) under a 12-15 lb pull, then torque the front chain adjustment nut to 210 ft. lbs. (285 Nm). Your machine is down. It's bookmarked by section and keyword-searchable, so pull it up on a tablet and start wrenching.
What's Inside This Mustang 930 & variants Manual
| System | Pages | Key Topics |
|---|---|---|
| Serial Number System | 4-5 | Serial Number System Breakdown, Serial Number Example (Fiscal Year 1990 Machine, Model 940, Sequence Number, Month of Build February), Service Manual Terminology |
| Specifications | 6-9 | 930 General Specifications, 940 General Specifications, 960 General Specifications |
| Safety Equipment | 10-18 | Roll Over Protective Structure (Removal and Installation), Lift Arm Stops, Seat Belt Lock-Out (Adjustments, Spool Lock Rod), Parking Brake (Adjustment), Neutral Start Switches |
| General Information | 19-33 | System Contamination Control, Hydraulic Fluid, Maintenance Chart, Pre-Delivery Check List, 50 Hour Check List, Access Panels, Standard Torque Value Specifications |
| Steering Controls | 34-41 | Troubleshooting, T-Bar Adjustments, T-Bar Removal and Installation, Neutral Centering Device Adjustments, Neutral Centering Device Service and Repair, Diagram |
| Hydraulic System | 42-64 | Troubleshooting, Pressure Check, Lift Circuit Leak Down Test, Tilt Circuit Leak Down Test, Hydraulic Cylinder Testing, Hydraulic Cylinder Service and Repair |
| Hydrostatic Drive System | 65-79 | Troubleshooting, Drive System Diagram, System Checks (Charge Pressure Checks, Directional Check / Relief Valve Combination, Closed Loop, Piston Pump, Hydrostatic Drive Motor) |
| Chain Case | 80-98 | Troubleshooting, Brake Assembly (Service and Repair I, Input Drive Shaft Service and Repair Ii) |
| Engine | 99-110 | Troubleshooting, Engine / Hydrostatic Pump Removal and Installation, Engine Components Removal and Installation, Cooling System, Cooling System Trouble Shooting, Fuel System |
| Electrical System | 111-120 | Troubleshooting, Wiring Diagram, & 940 Wiring Diagram, Instrument Panel, Starting Circuit, Starter Motor - Disassembly, Charging Circuit, Alternator - Disassembly |
| E-Series Service Manual | 121-122 | Applicable Models, Manual Supplement Information, Manual Identification, Manufacturer Contact Information |
| E-Series Interlock Explanation | 123-124 | Hydraulic Control Valve Spool Locks, Solenoid Control of Spool Locks and Fuel Lever, Safety Interlock Switches, Figure 9-1 Electric Solenoid, Figure 9-2 Fuel Solenoid |
| E-Series Wiring Diagram | 125 | Battery and Charging System, Starter Circuit, Fuel Solenoid and Interlock System, Instrument Panel Indicators, Lighting and Auxiliary Circuits |
| E-Series Troubleshooting | 126-127 | Engine Starts But Will Not Stay Running (Problem Same with Switch in Either Mode, Check Power Supply to Switch, Check for Faulty Switch, Fuel Solenoid, Or Open Circuit, Engine Runs in Red But Not in Green Mode, Check Operation of Lift Arm Bypass System, Lift Arm Bypass Works Ok, No Voltage in Purple Wire, Boom Override System Does Not Function) |
| E-Series Fuel Solenoid (930A - 940) | 128-129 | Removal (Remove: Engine Oil Dipstick, Fuel Filter Mounting Bolt, Solenoid Mounting Screws, Cotter Pin and Sprocket Nut) |
| E-Series Fuel Solenoid (920) | 130-131 | Removal (Remove Spring Clip and Disconnect Linkage, Remove Fuel Solenoid Mounting Bolts, Unplug and Remove Fuel Solenoid) |
| E-Series Electrical System Component Check | 132-133 | Mode Switch Test (Test in Red Mode, Continuity Test Terminal 2 to 3 and 4, Test in Green Mode, Continuity Test Terminal 2 to 1, Continuity Test Terminal 5 to 6, Switch Replacement) |
| E-Series Hydraulic System Explanation | 134 | Hydraulic Control Valve Main Relief, Work Port Relief in Lift Spool, Purpose of Work Port Reliefs, Electromagnetic Spool Locks |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| 930, 940, 960 | ||
| Drive motor flanged lock nuts torque | 75 ft. lbs (102 Nm) | p. 78 |
| All Models | ||
| Neutral switch torque | 40 ft./lbs. (54.2 Nm) | p. 37 |
| Drive chain deflection | 1/8 inch (3.2 mm) with 12-15 lbs (5.4 - 6.8 kg) pull | p. 86 |
| Drive chain front adjustment nut torque | 210 ft. lbs. (285 Nm) | p. 86 |
| Parking Brake Engagement | 40 - 50 lbs. (18-23 kg) | p. 17 |
| Tire Pressure | 40-45 PSI (2.7-3.1 Bar) | p. 22 |
| 1/2 - 13, S.A.E. Grade 2, Plain Head Torque | 39 Foot - Pounds | p. 27 |
| 930 | ||
| Engine Displacement | 83 CID (1362 cc) | p. 6 |
| HP @ Governed RPM | 28 HP (20.6 kW) @ 2800 RPM | p. 6 |
| Hydraulic Pressure Relief | 2000 PSI (138 Bar) | p. 6 |
| 930, 940 | ||
| Cooling System Capacity | 6.5 qts. (6.1 L) | p. 6 |
| 960 | ||
| Fuel Tank Capacity | 20 gal. (75.7 L) | p. 8 |
Mustang 930 & variants Common Problems This Manual Covers
Mustang 930 drive wheels not turning, chain slap, or final drive noise under heavy load p. 86
Pull the chaincase access covers, then inspect the drive chains and adjust tension. Confirm drive chain deflection sits at exactly 1/8 inch (3.2 mm) under a 12-15 lbs (5.4 - 6.8 kg) pull, per page 86. Swap out broken chains or stripped axle sprockets right away.
Manual Section: Chain Case Trouble ShootingLoader arms or attachment hydraulics jerk, stall, or drift during normal machine operation p. 29
Inspect the control valve and hydraulic cylinders for internal leakage. Tighten any loose 1 inch hydraulic hoses and tubing to a minimum of 75 Foot-Pounds, shown on page 29. Run a lift circuit leak down test to pin down worn cylinder seals.
Manual Section: Hydraulic SystemBrake drag, machine will not roll freely, or braking is inconsistent during operation p. 17
Examine the brake housing for wear and contaminated components. Adjust the parking brake linkage for smooth operation. Confirm engagement takes exactly 40 - 50 lbs. (18-23 kg) of force, per page 17. Free up any stuck cables or linkage.
Manual Section: Safety EquipmentMustang 920E hydrostatic drive overheating, loader not tracking straight, or the machine pulling to one side while traveling p. 22
Test the charge pressure and confirm the closed loop piston pump is working correctly. Inspect the wheels and inflate all tires to 40-45 PSI (2.7-3.1 Bar), as specified on page 22. Seat-test the directional check and relief valve combination.
Manual Section: Hydrostatic Drive System TroubleshootingFrequently Asked Questions
How do I reset the hydraulic pressure on a Mustang 930/940/960 skid steer?
To adjust the hydraulic pressure, locate the relief valve in the control valve on the pressure inlet side. Use a 3/16" hex key to turn the adjustment screw: clockwise to increase pressure or counterclockwise to decrease it. The standard hydraulic relief pressure for a Mustang 930 is 2000 P.S.I. (139.7 bar), and for 940/960 models, it is 2400 P.S.I. (165.4 bar).
What does the charge pressure warning mean on a Mustang 940E?
On a Mustang 940E, a charge pressure warning, often indicated by a faulty charge pressure switch (PS1, rated at 70 PSI), means that the interlock system is preventing hydraulic functions. If there is no voltage in the purple wire at timer terminal #1, it suggests a problem with the charge pressure switch, leading to locked spools.
What are the common error codes or fault symptoms on a Mustang skid steer?
The manual lists various fault symptoms across different systems rather than specific error codes. Common symptoms include hydraulic action being slow or jerky, oil overheating, engine stalling when using hydraulics, no drive in one or both sides, white or black smoke from the engine, engine not shutting off, and electrical issues like an undercharged battery or starting motor problems. For example, hydraulic system troubleshooting covers symptoms like 'No hydraulic action' or 'Oil overheats'.
How to reset Mustang 930 hydraulic system
To 'reset' the hydraulic system on a Mustang 930, you can adjust the hydraulic relief pressure. The standard setting for the 930 model is 2000 P.S.I. (139.7 bar). The relief valve, located in the control valve, can be adjusted using a 3/16" hex key to increase or decrease the pressure as needed. This procedure is detailed on page 56.
What format is this Mustang 930 & variants manual in?
Delivered as a 134-page searchable PDF that downloads the moment you check out. Open it on a laptop, tablet, or phone and bring it straight to the shop floor.
Can I print specific sections of this Mustang 930 & variants Service Manual?
Yes. Print as many copies as you like, with no restrictions. Plenty of mechanics run off just the section they're working from and keep it at the bench.
Are hydraulic system diagrams in this Mustang 930 & variants Service Manual?
Full hydraulic system diagrams are included, covering circuits, valve locations, and hydraulic component specs for the Mustang 930 & variants.
Document Quality
This document is a scanned PDF, and you can search and copy most of the text due to an OCR layer. The main body text is generally crisp and easy to read, though some larger headings show minor pixelation. Diagrams and illustrations are scanned images, so they may pixelate when zoomed, but labels are typically legible. Pages are mostly clean with occasional faint background noise, slight skew, and some visible ring binder holes. There are several blank pages throughout the document, often acting as separators or filler.
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