GEAR (23 Teeth) 3K7020 - Caterpillar

Remove And Install Crankshaft Main Bearings
START BY:a. remove oil pumpb. remove oil pan plate 1. On 3304 Engines remove No. 1, 3, and 5 main bearing caps (1). On 3306 engines remove No. 1, 3, 5 and 7 main bearing caps (1). Remove the lower halves of the main bearings from the main bearing caps.
If the crankshaft is turned in the wrong direction, the tab on the bearing will be pushed between the crankshaft and the bearing area in the cylinder block. This can result in damage to the cylinder block and/or the crankshaft.
2. Install tool (A) in the hole in the crankshaft journal, and turn the crankshaft to remove the upper halves of main bearings (2).3. Remove crankshaft thrust bearings (3) from the rear main bearing. Install the main bearings dry when the clearance checks are made. Put clean engine oil on the main bearings for final assembly.
Make sure the upper and lower halves of the main bearings are installed so the bearing tabs fit into the notch in the cylinder block and the main bearing caps.
4. Use tool (A), and install new upper halves of main bearings (2) in the cylinder block. Install new lower halves of main bearings (2) in main bearing caps (1). The serviceman must be very careful to use Plastigage correctly. The following points must be remembered:... Make sure that the backs of the bearings and the bores are clean and dry.... Make sure that the bearing locking tabs are properly seated in their slots.... The crankshaft must be free of oil where the Plastigage touches it.... If the main bearing clearances are checked with the engine upright or on its side, the crankshaft must be supported. Use a jack under an adjacent crankshaft counterweight and hold the crankshaft against the crown of the bearing. If the crankshaft is not supported, the weight of the crankshaft will cause incorrect readings.... Put a piece of Plastigage on the crown of the bearing half that is in the cap. Do not allow the Plastigage to extend over the edge of the bearing.... Install the bearing cap using the correct torque-turn specifications. Do not use an impact wrench. Be careful not to dislodge the bearing when the cap is installed.... Do not turn the crankshaft with the Plastigage installed.... Carefully remove the cap but do not remove the Plastigage. Measure the width of the Plastigage while it is in the bearing cap or on the crankshaft journal. Do this by using the correct scale on the package. Record the measurements.... Remove the Plastigage before reinstalling the cap.When using Plastigage, the readings can sometimes be unclear. For example, all parts of the Plastigage are not the same width. Measure the major widths to make sure that they are within the specification range. Also, experience has shown that when checking clearances tighter than 0.10 mm (.004") the readings may be low by 0.013 to 0.025 mm (.0005 to .0010"). Out-of-round journals can give faulty readings. Also, journal