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Home >> Chevrolet >> 2017 >> SS Automatic Trans >> Repair and Diagnosis >> Engine Mechanical >> Engine Mechanical - 6.2L (LS3) >> Repair Instructions - Off Vehicle >> Thread Repair >> Main Cap Bolt Hole Thread Repair
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Main Cap Bolt Hole Thread Repair

    Fig 1: Thread Repair Kit Components
    GM313556Courtesy of GENERAL MOTORS COMPANY
  1. The main cap bolt hole thread repair kit consists of the following items:
    • The drill (1)
    • The tap (2)
    • The installer (3)
    • The fixture plate (4)
    • The long bolts (5)
    • The short bolts (6)
    • The alignment pin (7)
    • The bushing (8)
    2. Fig 2: Fixture Plate, Bolt & Bushing
    GM377630Courtesy of GENERAL MOTORS COMPANY
  2. Install the fixture plate, bolt, and bushing onto the engine block.

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

  3. Position the alignment pin in the desired hole and tighten the fixture retaining bolts.
    4. Fig 3: Crankshaft Main Bearing Cap Bolt Tightening Sequence
    GM63214Courtesy of GENERAL MOTORS COMPANY
  4. Drill out the damaged hole.

    The outer bolt hole locations 11 - 20 have the shallower counterbores. Use sleeve J 42385-316 with the drill.

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

  5. Using compressed air, clean out any chips.
    6. Fig 4: Tap Upper & Lower Marks, Fixture Plate & Bushing
    GM377637Courtesy of GENERAL MOTORS COMPANY
  6. Using a tap wrench, tap the threads of the drilled hole.

    In order to tap the new threads to the proper depth, rotate the tap into the hole until the mark on the tap aligns with the top of the bushing.

    For the deeper main cap holes 1 - 10, rotate the tap until the upper mark (4) on the tap aligns with the top of the bushing (3).

    For the shallower main cap holes 11 - 20, rotate the tap until the lower mark (1) on the tap aligns with top of the bushing (3).

  7. Using compressed air, clean out any chips.
  8. Spray cleaner into the hole. Refer to Adhesives, Fluids, Lubricants, and Sealers  for recommended cleaner.
  9. Using compressed air, clean any cutting oil and chips out of the hole.
    10. Fig 5: Lubricating Installer Tool Using Driver Oil
    GM313562Courtesy of GENERAL MOTORS COMPANY
    NOTE:

    Do not allow oil or foreign material to contact the OD of the insert.

  10. Lubricate the threads of the installer tool (2) with the driver oil (1).
    11. Fig 6: Bushing Type Insert
    GM313567Courtesy of GENERAL MOTORS COMPANY
  11. Install the insert (2) onto the driver tool (1).
    12. Fig 7: Applying Threadlock To Insert
    GM313572Courtesy of GENERAL MOTORS COMPANY
  12. Apply threadlock LOCTITE™ 277, J 42385-109 (1), or equivalent, to the insert OD threads (2).
    13. Fig 8: Fixture Plate, Drill Bushing & Tool Marking
    GM377635Courtesy of GENERAL MOTORS COMPANY
    NOTE:

    The fixture plate and bushing remains installed onto the engine block during the insert installation procedure.

  13. Install the insert and driver (1) through the fixture plate and bushing and into the hole.

    Rotate the driver tool until the mark on the tool (3) aligns with the top of the bushing (2).

    The installer tool will tighten up before screwing completely through the insert. This is acceptable. You are forming the bottom threads of the insert and mechanically locking the insert to the base material threads.

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