PISTON 8J1818 - Caterpillar

Probable Causes
Diagnostic codes
Batteries
Battery cables
Starting circuit
Starting motor solenoid
Starting motor
Flywheel ring gear
Transmission
Engine accessories
Hydraulic cylinder lock
Internal engine problemRecommended Actions
Diagnostic Codes
Check for active diagnostic codes on the Caterpillar Electronic Technician (Cat ET). Troubleshoot any active codes before continuing with this procedure.Batteries and/or Battery Cables
Inspect the main power switch, battery posts, and battery cables for loose connections and 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 machine wiring to the starting motor solenoid.Note: The electronic control module (ECM) controls the signal to the start relay. The ECM receives voltage from the keyswitch when the keyswitch is in the START position. If the engine speed is zero rpm, then the ECM supplies current to the starting motor relay.
Ensure that the circuit for the start relay is operating properly. Refer to Troubleshooting, "Start Relay Circuit - Test".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.Transmission or 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