HOSE 7W9079 - Caterpillar

Probable Causes
Emergency stop switch
Batteries
Battery cables
Starting circuit
Starting motor solenoid
Starting motor
Flywheel ring gear
Engine accessories
Hydraulic cylinder lock
Internal engine problemRecommended Actions
Emergency Stop Switch
Verify that the emergency stop switch is in the OFF (out) position. If the switch is depressed, fuel injection is disabled and the engine will not crank. Refer to Troubleshooting, "Engine Shutdown Switch Circuit - Test".Batteries and/or Battery Cables
Inspect the main power switch, bus bars, battery posts, and battery cables for loose connections and for corrosion. If the battery cables are corroded, remove the battery cables and clean the battery cables. Tighten any loose connections.
Inspect the batteries.
Charge the batteries. Refer to Special Instruction, SEHS7633, "Battery Test Procedure".
Load test the batteries. Refer to Special Instruction, SEHS9249, "Use of 4C-4911 Battery Load Tester for 6, 8 and 12 Volt Lead Acid Batteries". Starting Motor Solenoid or Starting Circuit
Test the operation of the starting motor solenoid.
Check the wiring to the starting motor solenoid. Starting Motor or Flywheel Ring Gear
Test the operation of the starting motor.
Inspect the starter motor pinion and the flywheel ring gear for damage. Engine Accessories
Ensure free movement of the driveline.
Ensure that the timing pin was not left in the flywheel housing.
Remove any engine accessories that may lock up the engine and inspect any engine accessories that may lock up the engine. The following list illustrates examples of engine accessories that may lock up the engine:
Hydraulic pump that is driven from the rear gear group
Air compressor
Power steering pump
Engine oil pumpHydraulic Cylinder Lock
Check for fluid in the cylinders (hydraulic cylinder lock) by removing the individual unit injectors.Note: Drain the fuel from the cylinder head. Fuel will flow from the cylinder head into the cylinders when the unit injector is removed.Internal Engine Problem
Disassemble the engine. Refer to Disassembly and Assembly.
Inspect the internal components for the following conditions:
Seizure
Broken components
Bent components