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Home >> GMC >> 2000 >> Yukon Denali >> Repair and Diagnosis >> External Pages >> Different car >> Section 684 (Engine Mechanical - 4.3L (Unit Repair)) >> Repair Instructions >> Thread Repair

Thread Repair

WARNING: This page is about a different car, the 2002 GMC Sierra and 2002 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

General purpose thread repair kits are available commercially.

Important:  Refer to the thread repair kit manufacturer's instructions regarding the size of the drill and which tap to use.

Always avoid any buildup of chips. Back out the tap every few turns and remove the chips.

  1. Determine the size, the pitch, and the depth of the damaged thread.
  2. Adjust the stop collars on the cutting tool as needed. Tap the stop collars to the required depth.
  3. Drill out the damaged thread.
  4. Remove the chips.
  5. Apply clean engine oil to the top thread.
  6. Use the tap in order to cut new thread.
    Fig 1: Using Tap To Cut New Thread
    G01655110Courtesy of GENERAL MOTORS CORP.
  7. Clean the thread.
  8. Screw the thread insert onto the mandrel of the thread insert installer. Engage the tang of the thread insert onto the end of the mandrel.

    Important:  The thread insert should be flush to 1 turn below the surface.

  9. Fig 2: Using Thread Insert To Repair Thread
    G01655111Courtesy of GENERAL MOTORS CORP.
  10. Lubricate the thread insert with clean engine oil - except when installing in aluminum - and install the thread insert.
  11. If the tang of the thread insert does not break off when backing out the thread insert installer, break off the tang using a drift punch.