Crankshaft Main Bolt Hole Thread Repair

Tools Required 

J 42385-2000  Thread Insert Kit. See Special Tools and Equipment .

Important: 

• In order to repair some crankshaft main bolt holes it will be necessary to mount the fixture plate upside down.
• Do NOT remove the fixture plate prior to installing the insert with the installation driver. The fixture plate remains in position throughout the thread repair process.

The crankshaft main bearing bolt hole thread repair kit J 42385-2000  components consist of the following:

• Drill (1) J 42385-511
• Tap (2) J 42385-512
• Installation driver (3) J 42385-513
• Fixture plate (4) J 42385-306
• Bushing (5) J 42385-307
• Alignment pin (6) J 42385-308
• Bolts (7) J 42385-510

Important: 

• Ensure the fixture plate is installed during the machining and installation processes of the insert.
• The use of a cutting type fluid GM P/N 1052864, (Canadian P/N 992881), WD 40® or equivalent is recommended when performing the drilling, counterboring and tapping procedures.

When installed to the proper depth, the flange of the insert will be seated against the counterbore of the drilled/tapped hole.

1. Position the fixture plate (3) with the bushing (2), installed over the crankshaft main cap bolt hole to be repaired.
2. Loosely install the fixture plate bolts (1) into the remaining crankshaft main cap bolt holes.
   Fig 2: View Of Fixture Plate & Bolts

   Courtesy of GENERAL MOTORS CORP.
3. Position the alignment pin (1) through the bushing and into the crankshaft main cap bolt hole.
4. With the alignment pin in the desired crankshaft main cap bolt hole, tighten the fixture retaining bolts (2).
5. Remove the alignment pin (1) from the crankshaft main cap bolt hole.
   Fig 3: Identifying Alignment Pin

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   Important: 

   • During the drilling process, it is necessary to repeatedly remove the drill and clean chips from the hole and the flutes of the drill.
   • Drill the crankshaft main bolt hole until the mark (1) on the drill aligns with the top of the drill bushing (2).
6. Drill out the threads of the damaged hole.
   Fig 4: Drilling Damaged Hole Threads

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   Important:  All chips must be removed from the drilled hole prior to tapping.

7. Using compressed air, clean out any chips.
   Fig 5: Removing Chips From Drill Hole

   Courtesy of GENERAL MOTORS CORP.

   Important: 

   • Do not remove the fixture plate, ensure the fixture plate is installed during the machining and installation processes of the insert.
   • During the tapping process, it is necessary to repeatedly remove the tap and clean chips from the hole and the flutes of the tap.
   • Ensure the tap has created full threads at least to the depth equal to the insert length.
8. Using a suitable tapping wrench, tap the threads of the drilled hole.
   Fig 6: Tapping Drilled Hole Thread

   Courtesy of GENERAL MOTORS CORP.
9. In order to tap the new threads for the insert to the proper depth, rotate the tap into the crankshaft main cap bolt hole until the mark (3) on the tap aligns with the top of the drill bushing (2).
   Fig 7: Identifying Alignment Mark On Tap

   Courtesy of GENERAL MOTORS CORP.

   Important:  All chips must be removed from the tapped hole prior to insert installation.

10. Using compressed air, clean out any chips.
    Fig 8: Removing Chips From Drill Hole

    Courtesy of GENERAL MOTORS CORP.
11. Spray cleaner GM P/N 12346139, GM P/N 12377981 (Canadian P/N 10953463) or equivalent into the tapped hole.
    Fig 9: Applying Spray Cleaner Into Tapped Hole

    Courtesy of GENERAL MOTORS CORP.

    Important:  All chips must be removed from the tapped hole prior to insert installation.

12. Using compressed air, clean out any chips.
    Fig 10: Removing Chips From Drill Hole

    Courtesy of GENERAL MOTORS CORP.

    Important: 

    • Do not remove the fixture plate, ensure the fixture plate is installed during the installation process of the insert.
    • Do not allow oil or other foreign material to contact the outside diameter (OD) of the insert.
13. Lubricate the threads of the driver installation tool (2) with the driver oil (1) J 42385-110.
    Fig 11: Lubricating Driver Installation Tool Thread

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14. Install the insert (2) onto the driver installation tool (1).
    Fig 12: Installing Insert Onto Driver Installation Tool

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15. Apply threadlock sealant GM P/N 12345493, (Canadian P/N 10953488), J 42385-109, LOCTITE 277® or equivalent (1) to the insert OD threads (2).
    Fig 13: Applying Threadlock Sealant To Insert Threads

    Courtesy of GENERAL MOTORS CORP.
16. Install the insert and installation driver into the tapped hole.
17. Start the insert into the threaded hole.

    Important:  If the insert will not thread down until the flange contacts the counterbored surface remove the insert immediately with a screw extracting tool and inspect the tapped hole for any remaining chips and/or improper tapping.

18. Install the insert until the flange of the insert contacts the counterbored surface.

    Important:  The driver installation tool will tighten up before screwing completely through the insert. This is acceptable. The threads at the bottom of the insert are being formed and the insert is mechanically locking the insert into the base material threads.

19. Continue to rotate the driver installation tool through the insert.
    Fig 14: Installing Insert & Installation Driver Into Tapped Hole

    Courtesy of GENERAL MOTORS CORP.
20. Rotate the driver installation tool until the mark (3) on the driver installation tool aligns with the top of the drill bushing (2).
21. Inspect the insert for proper installation into the tapped hole.
    Fig 15: Locating Installation Mark On Tap

    Courtesy of GENERAL MOTORS CORP.
22. Remove the fixture plate bolts (1).
23. Remove the fixture plate (3) and bushing (2).
    Fig 16: Removing Fixture Plate & Bolts

    Courtesy of GENERAL MOTORS CORP.