Cylinder Head Bolt Hole Thread Repair

The cylinder head bolt hole thread repair kit consists of the following items:
- Drill (1)
- Tap (2)
- Installer (3)
- Sleeve (4)
- Alignment Pin (5)
- Bushing (6)
- Bolts (7)
- Fixture Plate (8)

Fig 1: Identifying Thread Repair Kit Components

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CAUTION: Refer to Safety Glasses Caution in Cautions and Notices.

IMPORTANT: The use of a cutting type fluid P/N 1052864, 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 are designed for use with either a suitable tap wrench or drill motor.

Install the fixture plate (3), bolts (1), and bushing (2) onto the engine block deck.
Position the fixture plate and bushing over the hole that is to be repaired (4).

Fig 2: Installing Fixture Plate, Bolts, & Bushing

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Position the alignment pin (1) through the bushing and into the hole.

Fig 3: Identifying Alignment Pin

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With the alignment pin in the desired hole, tighten the fixture retaining bolts (2).
Remove the alignment pin from the hole.
Install the sleeve (2) onto the drill (1), if required.

Fig 4: View Of Stop Collar & Counterbore Drill

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

Drill out the threads of the damaged hole.
Drill the hole until the stop collar of the drill bit or the sleeve contacts the bushing.

Fig 5: Drilling Out Threads Of Damaged Hole

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Using compressed air, clean out any chips.
Using a tap wrench, tap the threads of the drilled hole.

Fig 6: Tapping Threads Of Drilled Hole With Tap Wrench

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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 align with the top of the drill bushing (2).

Fig 7: View Of Fixture Plate, Drill Bushing & Tool Marking

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Remove the fixture plate (1), bushing (2), and bolts.
Using compressed air, clean out any chips.
Spray cleaner GM P/N 12346139, GM P/N 12377981, 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 8: Lubricating Installer Tool Using Driver Oil

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Install the insert (2) onto the driver tool (1).

Fig 9: View of Bushing Type Insert

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Apply threadlock LOCTITE™ 277, J 42385-109 (1), or equivalent to the insert OD threads (2).

Fig 10: Applying Threadlock To Insert

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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.

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.

Fig 11: Installing & Inserting Driver Into Hole

Courtesy of GENERAL MOTORS CORP.