Smaller Connecting Rod Bolt Used In 4W6425 Air Compressor; Use Correct Torque
Usage:
3406B Truck Engines
The connecting rod bolt size has changed from 5/16 to 1/4 inch in the 4W6425 Midland-Ross Air Compressor (two cylinder). Air compressors with both bolt sizes are in the field.
Caterpillar and Midland-Ross publications specify a torque of 21 to 25 N ·m (185 to 225 lb in) in the assembly procedure. This is the correct torque for the 5/16 bolts
The correct torque for the 1/4 bolts is 12 to 15 N·m (105 to 135 lb in). Make note of this change in your publications.
NOTE: Both of these are standard bolt torques.
Caterpillar Information System:
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