SENSOR GP-NITROGEN OXIDE 3044209 - Caterpillar

Remove Crankshaft Main Bearings
Start By:a. remove piston cooling jets In some cases, seagoing vessels require periodic main bearing inspection. Normally bearing inspection would be difficult because of the inaccessibility and weight of the main bearing caps. The FT1794 Crankshaft Main Bearing Removal Tool Group simplifies this inspection procedure. See Special Instruction, Form No. SMHS8331, for the complete inspection procedure.1. Drain the oil from the pan. 2. Use tool (A) to turn the engine flywheel to move counterweights (1) in position for removal. Remove counterweights (1) from the crankshaft through the side of the cylinder block.3. Use tool (A), and turn the engine flywheel to move the connecting rod bearing surface (journal) to the top center position. 4. Use tool (B), and loosen the four bolts that hold the main bearing cap in position.5. Hold the main bearing cap in position with a pry bar, and remove the bolts. Lower the bearing cap from the cylinder block.6. Remove the bearing caps from the side of the engine. The weight of each bearing cap is 16 kg (35 lb.). 7. Remove lower bearing half (2) from bearing cap (3). 8. Remove thrust plates (4) from each side of the center main bearing.
If the crankshaft is turned in the wrong direction, the tab of the bearing will be pushed between the crankshaft and cylinder block. This can cause damage to either or both.
On the center main journal that has no oil hole, put a thin piece of soft material that will not damage the crankshaft journal against the end of the bearing, opposite the tab. Hit the bearing with the soft material until the tab of the bearing is free from the cylinder block. Remove the upper half of the main bearing. 9. Install tool (C) in the oil hole in the crankshaft journal, and remove upper main bearing halves (5) as the crankshaft is turned and the bearing is moved out of the cylinder block.Install Crankshaft Main Bearings
Make sure the upper and lower bearings are installed so the bearing tabs fit into the notch in the cylinder block and bearing caps. Install the main bearings dry when clearance checks are made. Put clean engine oil on the main bearings for final assembly. For complete details concerning measuring bearing clearances, see Engine Bearings And Crankshafts, Form No. SEBD0531.
1. Install tool (B) in the oil hole of the crankshaft. Put the upper bearing half (half with oil hole) in position on the crankshaft. Use tool (A) to turn the engine flywheel, and push the bearing half in position with tool (B).2. Make sure the bearing caps are clean, and install the lower bearing halves in the caps.
When Plastigage is used to check bearing clearances, do not use an impact wrench for the torque tightening sequence.
When the bearing clearance is checked and the engine is in a vertical position, such as in the vehicle, the crankshaft will have to be lifted up and held against the upper halves of the main bearing to