Inspection and/or Repair Procedure to Replace Broken Crankshafts in C-15, C-16, C15, 3406C, 3406E, and 3456 Engines{1202} Caterpillar

Introduction

AVSpare recommends reading and understanding this procedure completely before attempting any of the repairs that are described.

This procedure was developed in order to provide a higher quality and a lower cost repair for a broken crankshaft.

Inspection and/or Repair Procedure to Replace Broken Crankshafts in 3406C, C-15, C-16, C15, 3406E, and 3456 Engines

1. Remove the engine from the chassis.

2. Remove all the rod caps from all of the connecting rods.

3. For each connecting rod, inspect the large end of the rod bore, parting line area, all connecting rod caps, hardware seating area, lower shank area, and hardware for damage. Refer to Visual Inspection of Connecting Rods, SEBF8063, "Guidelines for Reusable Parts and Salvage Operations" and Salvage of Non-Serrated Connecting Rods, SEBF8064, "Guidelines for Reusable Parts and Salvage Operations" for more information. Also inspect the bottom ends of each piston skirt and each liner for damage. If there is no indication of damage to the components in the upper end, it is not necessary to inspect the small end of the connecting rod. If the connecting rods are OK for use proceed to Step 4. If the connecting rods are damaged replace the connecting rods with a Reman version. Also, if the piston is damaged, the cylinder pack must be replaced. Refer to ""Alternative Repair Options" " for more information.

4. Push the piston and the connecting rod up to the top of the liner bore.

5. Remove the main bearings, thrust plates, and the crankshaft. Remove the oil filter from the engine. In order to inspect the oil filter for evidence of metal debris, the oil filter must be cut open. The oil pump and oil filter base must be disassembled, inspected, and cleaned if debris is present and the debris exceeds three particles (1 mm) per pleat. The oil cooler core must be replaced with a Reman part. Continue to inspect all main bearings for scratches due to debris. Scratches on the main bearing due to debris indicate that metal particles exist on the filtered side of the lubrication system. If scratches due to debris are present on one or more of the main bearings, the complete lubrication system must be flushed.

6. Inspect the main bearing bore diameter of the cylinder block for damage. If there are no signs of damage proceed to Step 7. If damage is present and the damage is due to a buildup of irregular material, proceed to Step 6.a.

   1. Position the engine in a vertical position in order to avoid contamination from debris. Remove any debris or remove any buildup of a metal ridge from the main bearing bore with a small pencil grinder.

      Note: Remove enough of the metal buildup in order to allow the new main bearing to fully seat in the bore. Do not use an emery cloth over the large area of the bore. Use magnets to avoid further contamination from debris. It may be necessary to machine the main bore to a larger diameter in order to remove damage or it might be necessary to machine the main bore to a larger diameter in order to allow the use of a new oversized bearing. All of the main bearing bores must be machined to the same size.

   2. If the buildup of material has been removed proceed to Step 7. If the buildup is too excessive or if the wear is too excessive, proceed to ""Alternative Repair Options" ".

7. Inspect the cylinder block bore on both the bearing cap and the block. No damage is allowed on the block and/or on the main cap for the thrust bearing (#4 Main Position). The new main bearing is allowed to overhang the side of the cap and bore of the block up to 2.5 mm (0.0984 inch) maximum for the other six main caps. If the width of the bore on the main cap and the block meet these requirements, proceed to Step 8. If the width does not meet these requirements proceed to ""Alternative Repair Options" ".

8. Inspect the alignment of the main bearing bore. Refer to Engine Bearings, SEBV0544 for more instructions.

   Note: Using a boring machine to check the alignment of the main bearing bore is the most accurate method. However, a long machinist's straightedge and a feeler gauge can be used in order to check the alignment of the main bearing bore. The following procedure describes using a feeler gauge and a machinist's straightedge in order to check the alignment of the main bearing bore.

   1. Place a 0.0381 mm (0.0015 inch) feeler gauge in the bore and then lay the straightedge across it and several of the crankshaft bores. Do not put pressure on the straightedge.

   2. Check if the feeler gauge pulls out freely. If the feeler gauge pulls out freely, that bore is not in alignment.

   3. Check the alignment of each main bore by using this procedure.

      Note: In checking the alignment of the main bearing bore, the machinist's straightedge must be handled carefully in order to prevent nicks and/or burrs. Also, it is important to support the engine block evenly so the measurements are accurate.

9. Inspect the threads for main bearings in the cylinder block. Also, inspect the holes of the main bearing cap for signs of cracks. Use denatured alcohol as a cleaner and 4C-4804 Penetrant and 4C-4805 Developer in order to help identify cracks.

10. If the crankshaft breaks only between the rear fillet of rod journal #6 and the front of fillet of main journal #7, then it is unlikely that there is any damage to the gears of the front gear train. If there were no indications of damage prior to the crankshaft failure, during the crankshaft failure, or after the crankshaft failure, proceed to Step 11. If the front gear train has been damaged refer to Guidelines for Reusable Parts And Salvage Operations, "Timing Gears for All Engines". If there is damage to the front gear train, replace the gears or proceed to ""Alternative Repair Options" ".

11. If the crankshaft breaks only between the rear fillet of rod journal #6 and the front fillet of main journal #7, then it is unlikely that there is any damage to the connecting rods, pistons, or other top end components of the valve train. If there were no indications of damage prior to the crankshaft failure, during the crankshaft failure, or after the crankshaft failure, proceed to Step 12. Otherwise, inspect the top end (valves, pistons, etc) for further collateral damage. If there is damage to the valve train components, replace the damaged components or proceed to ""Alternative Repair Options" ".

12. Inspect the crankshaft damper for damage. Refer to Operation and Maintenance Manual, "Crankshaft Vibration Damper - Inspect". if no damage is present proceed to Step 13. If damage is found replace the crankshaft damper. Refer to Disassembly and Assembly, "Vibration damper and Pulley - Remove and Install".

13. Install new thrust plates. Also install a Reman crankshaft, and install new properly sized main bearings and rod bearings.

Alternative Repair Options

1. Line bore the cylinder block and replace the crankshaft. Also replace any other damaged components.

   Note: This option is used when the cylinder block can be salvaged by performing a line bore procedure.

2. Replace the damaged engine block with a short block and replace all other damaged components.

   Note: This option should only be used when the engine block is not able to be salvaged.

3. Perform a OPT overhaul.

4. Replace the engine with a Reman engine.

   Note: This option is used when the total cost of repairing the engine is higher than the price of a complete Reman engine.