Main Cap Bolt Hole Thread Repair

The main cap bolt hole thread repair kit consists of the following items.
- Drill (1)
- Tap (2)
- Installer (3)
- Fixture Plate (4)
- Long Bolts (5)
- Short Bolts (6)
- Alignment Pin (7)
- Bushing (8)
  
  Fig 1: Identifying Main Cap Bolt Hole Thread Repair Kit
  Courtesy of GENERAL MOTORS CORP.
Remove the alignment dowel pins from the holes (1-4), if necessary.

Fig 2: Identifying Alignment Dowel Pins
Courtesy of GENERAL MOTORS CORP.
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.

Fig 3: Installing Fixture Plate, Bolt & Bushing Onto Block
Courtesy of GENERAL MOTORS CORP.
Position the alignment pin in the desired hole and tighten the fixture retaining bolts.
Drill out the damaged hole.
Using compressed air, clean out any chips.
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 (3) on the tap aligns with the top of the bushing (2).

Fig 4: Tapping Threads Of Drilled Hole
Courtesy of GENERAL MOTORS CORP.
Using compressed air, clean out any chips.
Spray cleaner GM P/N 12346139 (Canadian P/N 10953463) or equivalent, into the hole.
Using compressed air, clean any cutting oil and chips out of the hole.
Important: Do not allow oil or other foreign material to contact the outside diameter (OD) of the insert.
Lubricate the threads of the installer tool (2) with the driver oil (1).

Fig 5: Lubricating Threads Of Installer Tool With Driver Oil
Courtesy of GENERAL MOTORS CORP.
Install the insert (2) onto the driver tool (1).

Fig 6: Installing Insert Onto Driver Tool
Courtesy of GENERAL MOTORS CORP.
Apply threadlock LOCTITE^TM 277, J 42385-109 (1), or equivalent to the insert OD threads (2).

Fig 7: Applying Threadlock To Insert OD Threads
Courtesy of GENERAL MOTORS CORP.

Important: The fixture plate and bushing remains installed onto the engine block during the insert installation procedure.
Install the insert and driver through the bushing (2), fixture plate (1) 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.
Remove the driver, bushing (2), fixture plate (1), and bolts.

Fig 8: Installing Insert
Courtesy of GENERAL MOTORS CORP.
Install the alignment dowel pins in holes (1-4), if necessary.

Fig 9: Installing Alignment Dowel Pins
Courtesy of GENERAL MOTORS CORP.