BOLT 4B3903 - Caterpillar

Removal Procedure
Table 1
Required Tools    
Tool     Part Number     Part Description     Qty    
A     150-3992     Timing Pin (1)     1    
150-3993 Timing Pin (2)     1    
B     173-9774     Bolt Remover     1    
( 1 ) The timing pin is required in order to install Bosch fuel injection pumps.
( 2 ) The timing pin is required in order to install Lucas and Stanadyne fuel injection pumps.Start By:
Remove the water pump. Refer to Disassembly and Assembly, "Water Pump - Remove".
Remove the fuel injection lines. Refer to Disassembly and Assembly, "Fuel Injection Lines - Remove and Install".Note: Access to the fuel injection pump gear can also be gained by the removal of an access cover on the front housing. The cover may have bolts that are tamperproof. The bolts can be removed with Tool (B).
Keep all parts clean from contaminants.Contaminants may cause rapid wear and shortened component life.
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids.Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on Caterpillar products.Dispose of all fluids according to local regulations and mandates.
Ensure that the number 1 cylinder is at the top center position on the compression stroke. Refer to the Testing and Adjusting, "Fuel System" topic for additional information.
Illustration 1 g00567390
Typical example
Illustration 2 g00567399
Typical exampleNote: Do not remove hub nut (4) from the shaft of the fuel injection pump. The hub of the fuel injection pump is installed in the correct position from the factory in order to ensure proper timing. If hub nut (4) is removed and the hub is removed, the hub will need to be accurately installed on the shaft of the fuel injection pump. Special equipment is available at your Caterpillar Dealer for this procedure.Note: Do not release torx screws (5). If the torx screws are released and the timing plate is moved, the timing position that is set at the factory will be lost. If the torx screws are released, the number 1 cylinder must be set to the top center position on the compression stroke before the torx screws are tightened.
Slowly rotate the crankshaft until hole (6) in the timing gear and hole (7) in the hub are in alignment with hole (8) in the fuel injection pump body .Note: The location of Tool (A) for Bosch fuel injection pumps will be located toward the top of the fuel injection pump. The location of Tool (A) for Lucas and Stanadyne fuel injection pumps will be located toward the bottom of the fuel injection pump.
Install Tool (A) through hole (6) in the timing gear and hole (7) in the hub. Push Tool (A) into position in hole (8) in the fuel injection pump body. If