D343 INDUSTRIAL & MARINE ENGINES Caterpillar


Crankshaft Main Bearings

Usage:

Remove And Install Crankshaft Main Bearings

preparatory steps:

a) remove oil pump

b) remove oil pan plate (industrial engine only)

1. Remove the No. 2 and No. 6 main bearing caps.

2. Using tool (A), remove the upper halves of main bearings by placing the tool in drilled oil hole in crankshaft, and rotating the crankshaft in the direction which will force the bearing out tab first.


NOTICE

If crankshaft is rotated in the wrong direction, the outward tab on bearing will be forced between the crankshaft and bearing saddle which might damage either or both.


3. Remove the lower halves of bearings from caps.

4. Lubricate the bearing surfaces of upper halves of main bearings with clean SAE 30 engine oil. Clean and dry the back side of main bearings.

5. Using tool (A), install the upper halves of main bearings by rotating the bearing into position tab end last.


NOTICE

Make certain the upper halves of bearings and lower halves of bearings are installed so the bearing tabs fit into the recesses in cylinder block and bearing cap.


6. Clean the mating surfaces of bearing cap and bearing. Place the lower halves of main bearings in the bearing caps.

7. Using wire (B), check the crankshaft main bearing clearance as follows:

a) Place two pieces of wire (B) diagonally on the lower half of bearing.

b) Position the main bearing cap on cylinder block with number stamped on cap facing the corresponding number stamped on oil pan rail on left side of cylinder block.

c) Install the cap retaining nuts and washers. Tighten nuts initially to 75 ± 5 lb. ft. (10,4 ± 0,69 mkg). Mark both nuts and bearing caps and tighten both nuts an additional 120° from mark.

d) Remove the bearing caps, and measure the thickness of wire (B). Main bearing clearance should be .0035-.0066 in. (0,088-0,167 mm). Maximum permissible main bearing clearance is .009 in. (0,22 mm).

8. Lubricate the threads of cap retaining studs, face of washers, and lower halves of main bearings with clean SAE 30 engine oil.

9. Position the main bearing caps on cylinder block with number stamped on facing the corresponding number stamped on oil pan rail on left side of cylinder block.

10. Install the cap retaining nuts and washers. Tighten nuts evenly to an initial torque of 75 ± 5 lb. ft. (10,4 ± 0,69 mkg). Mark both nuts and bearing caps, and tighten each nut an additional 120° from its respective mark.

11. Remove the No. 1,3,4,5, and 7 main bearing caps.

12. Repeat Steps 2 through 10 for the remaining bearings.

13. Using indicator group (C), check the crankshaft end play as controlled by the lower half of crankshaft rear main bearing. End play should be .006-.018 in. (0,152-0,457 mm). Maximum permissible end play is .035 in. (0,88 mm).

concluding steps:

a) install oil pan plate

b) install oil pump

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