Cylinder Head Bolt Hole Thread Repair

Tools Required 

• J 42385-600  Thread Repair Kit
• J 42385-300  Fixtures and Hardware Kit

1. The cylinder head bolt hole thread repair kit J 42385-600  and J 42385-300  consists of the following items:
   • Drill (1)
   • Tap (2)
   • Installer (3)
   • Stop collar (4), for shallow holes
   • Alignment pin (5)
   • Bushing (6)
   • Bolts (7)
   • Fixture plate (8)
   Fig 1: Cylinder Head Bolt Hole Thread Repair Kit

   
   CAUTION: Refer to SAFETY GLASSES CAUTION in Cautions and Notices.

   Important:  The use of a cutting type fluid GM P/N United States 1052864, GM P/N Canada 992881, WD 40®, or equivalent is recommended when performing the drilling and tapping procedures.

   Driver oil MUST be used on the installer driver tool.

   The tool kits J 42385-600  and J 42385-300  are designed for use with either a suitable tap wrench or drill motor.

   Fig 2: Installing Fixture Plate, Bolts, And Bushing Onto Engine Block Deck

   
2. Install the fixture plate (3), bolts (2), and bushing (1) onto the engine block deck.

   Position the fixture plate and bushing over the hole that is to be repaired (4).

3. Position the alignment pin (1) through the bushing and into the hole.
4. With the alignment pin in the desired hole, tighten the fixture bolts (2).
5. Remove the alignment pin from the hole.
6. The left cylinder head bolt holes 805-808 are deep holes and will be drilled without an additional stop collar.
7. The left cylinder head bolt holes 801-804 are shallow holes and will be drilled with an additional stop collar.
8. The right cylinder head bolt holes 705-708 are deep holes and will be drilled without an additional stop collar.
9. The right cylinder head bolt holes 701-704 are shallow holes and will be drilled with an additional stop collar.
   Fig 3: Position Alignment Pin Through Bushing And Into Hole

   
10. Install the stop collar (2) onto the drill (1) if required.
    Fig 4: Installing Stop Collar Onto Drill

    

    Important:  During the reaming process, it is necessary to repeatedly remove the drill and clean the chips from the hole.

11. Drill out the threads of the damaged hole.

    Drill the hole until the stop collar of the drill bit or the added stop collar contacts the bushing.

    Fig 5: Drilling Out Threads Of Damaged Hole

    

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

12. Using compressed air, clean out any chips.
    Fig 6: Clean Out Chips Using Compressed Air

    
13. Using a tap wrench, tap the threads of the drilled hole.
    Fig 7: Tapping Threads Of Drilled Hole Using Tap Wrench

    
14. In order to tap the new threads to the proper depth, rotate the tap into the hole until the marks (1 or 4) on the tap align with the top of the drill bushing (3).

    For the deeper cylinder head bolt holes, 705-708 or 805-808, rotate the tap until the upper mark on the tap (4) aligns with the top of the drill bushing.

    For the shallower cylinder head bolt holes, 701-704 or 801-804, rotate the tap until the lower mark on the tap (1) aligns with the top of the drill bushing.

15. Remove the fixture plate (2), bushing (3), and bolts.
    Fig 8: Removing Fixture Plate, Bushing And Bolts

    

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

16. Using compressed air, clean out any chips.
    Fig 9: Cleaning Out Chips Using Compressed Air

    
17. Spray cleaner GM P/N United States 12346139, GM P/N United States 12377981, GM P/N Canada 10953463, or equivalent into the hole.
    Fig 10: Spraying Cleaner Into Hole

    

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

18. Using compressed air, clean any cutting oil and chips out of the hole.
    Fig 11: Cleaning Out Cutting Oil And Chips Using Compressed Air

    

    Important:  Do not allow oil or other foreign material to contact the outside diameter (OD) of the insert.

19. Lubricate the threads of the installer tool (2) with the driver oil (1).
    Fig 12: Lubricating Threads Of Installer Tool With Driver Oil

    
20. Install the insert (2) onto the driver tool (1).
    Fig 13: Installing Insert Onto Driver Tool

    
21. Apply threadlock Loctite® 277, J 42385-109 (1), or equivalent to the insert OD threads (2).
    Fig 14: Applying Threadlock To Insert OD Threads

    

    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.

22. Install the insert and driver (1) into the hole.

    Rotate the driver tool until the mark on the tool aligns with the deck surface of the engine block.

    Fig 15: Installing Insert And Driver Into Hole