Thread Repair Except Cylinder Head/Main Cap Bolts

Tools Required

J 39345 Thread Repair Kit

The following procedure is used to accomplish proper and durable thread repairs except for thread repairs in the cylinder head and the cylinder block. Only holes specified in this procedure are serviceable.

Important: Take appropriate precautions to assure that machining chips will not remain inside the engine. For example, block all intake passages, oil drainback holes and exhaust passages with a towel or tape before performing thread repairs.

1. Select the proper size drill as indicated in the schematic charts found in the Thread Repair Specifications for the hole being repaired.
2. Drill out the damaged threads to the original depth or completely through for through holes.

Caution: Wear safety glasses in order to avoid eye damage.

3. Clean out the hole using compressed air with a shop rag wrapped around the air spout to prevent aluminum chips from leaving the hole.



4. Select the correct size tap, using the appropriate chart for the hole being repaired.
5. Coat the tap and the hole with spray machining oil.
6. Tap the hole to the original depth. In order to clean the threads, reverse the rotation of the tap periodically.
7. Use aluminum safe solvent to clean out all of the aluminum chips.
8. Apply compressed air with a shop towel wrapped around the air spout, in order to retain the chips forced out of the hole.
9. Tap the hole again to clean the threads. The tap should thread in with little resistance.

Important: Make sure all of the aluminum chips are cleared from the hole.

10. Use aluminum safe solvent to clean out all of the aluminum chips.
11. Apply compressed air with a shop towel wrapped around the air spout, in order to retain the chips forced out of the hole.
12. Use a flashlight to confirm that all of the chips are removed from the hole.
13. Continue to clean the hole until all of the aluminum chips are cleared.
14. Install the heli-coil insert as follows:

14.1.

In order to determine the correct size installation tool and length insert, refer to the appropriate picture and chart.

14.2.

Screw the insert on the mandrel of the installation tool until the driving tang is fully engaged in the driving contour.

14.3.

Coat the insert with spray machining oil.

14.4.

Install the insert as follows:

14.4.1.

Slide the prewinder over the mandrel and insert.

14.4.2.

Rotate the mandrel clockwise until 1 or 2 threads of the insert are threaded into the prewinder.

14.4.3.

Place the insert in position on the threaded hole being repaired.

14.4.4.

Rotate the mandrel clockwise until the insert is flush with the top surface of the threaded hole.

14.4.5.

Remove the prewinder except when repairing cylinder head bolts.

14.4.6.

Continue to install the insert until reaching the original thread depth.

14.4.7.

Remove the mandrel.

14.5.

Remove the driving tang from the thread insert as follows. The tang must be removed in order to allow passage of the fastener through the insert.

14.5.1.

Place the square end of the punch, no chamfer, on the tang after installation.

14.5.2.

Strike the punch sharply with the hammer. The tang will break off at the notch.

15. Clean the hole using compressed air. Take appropriate steps to assure that chips are not blown into the engine.

Thread Repair Cylinder Head/Main Cap Bolts

Tools Required

The thread repair process involves a solid, thin walled, self-locking, carbon steel, bushing type insert. During the insert installation process, the installation driver tool cold-rolls the bottom internal threads and expands the bottom external threads of the insert into the base material. This action mechanically locks the insert into place.

The drill bit and counter bore tool from the tool kit J-42385-500 is designed for use with either a suitable tap wrench or drill motor. Limited access and larger hole repair may process better using a tap wrench. An extension from kit J 43965 may also be necessary to drive the thread repair tooling dependent on access to the hole being repaired. Use only a tap wrench when tapping the hole and during installation of the insert.

It is critical that the drilling, counterboring and tapping of the hole to be repaired follows the same centerline as the original hole.

During the drilling and tapping of the hole being repaired ensure the tooling is consistently machining perpendicular to the surface of the base material.

If the threaded hole being repaired has a base surface perpendicular to the hole centerline, tapping guides are available to aid in tapping the hole.

Tap Size	Tap Guide	Tape Size	Tape Guide	Tap Size	Tape Guide
--	J 42385-	--	J 42385-	--	J 42385-
6 x 1.0	729	10 x 1.5	731	14 x 1.5	736
8 x 1.25	730	12 x 1.5	732	20 x 1.5	737

Standard Thread Repair - Flush Hole

Caution: Wear safety glasses in order to avoid eye damage.

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

When installed to the proper depth, the flange (1) of the insert will be seated against the counterbore of the drilled/tapped hole and just below the surface (2) of the base material.

Important: 

•	During the drilling process, it is necessary to repeatedly remove the drill and clean chips from the hole and the flutes of the drill.

•	DO NOT drill any further than the original hole depth.

1. Drill out the threads of the damaged hole.

•	M6 inserts require a minimum drill depth of 15 mm (0.59 in).

•	M8 inserts require a minimum drill depth of 20 mm (0.79 in).

•	M10 inserts require a minimum drill depth of 23.5 mm (0.93 in).





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

2. Using compressed air, clean out any chips.




Important: A properly counterbored hole will show a slight burnishing on the surface of the base material for 360 degrees around the drilled hole.

3. Counterbore the drilled hole to the full depth permitted by the tool (1).




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

4. Using compressed air, clean out any chips.




Important: 

•	During the tapping process, it is necessary to repeatedly remove the tap and clean chips from the hole and the flutes of the tap.

•	Ensure the tap has created full threads at least to the depth equal to the insert length.

5. Using a suitable tapping wrench, tap the threads of the drilled hole by hand only.

•	M6 inserts require a minimum tap depth of 15 mm (0.59 in).

•	M8 inserts require a minimum tap depth of 20 mm (0.79 in).

•	M10 inserts require a minimum tap depth of 23.5 mm (0.93 in).





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

6. Using compressed air, clean out any chips.



7. Spray cleaner GM P/N 12346139, GM P/N 12377981 (Canadian P/N 10953463) or equivalent into the tapped hole.




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

8. Using compressed air, clean out any chips.




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

9. Lubricate the threads of the driver installation tool (2) with the driver oil J 42385-110 (1).



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



11. Apply threadlock sealant GM P/N 12345493, (Canadian P/N 10953488), J 42385-109, LOCTITE 277® or equivalent (1) to the insert OD threads (2).



12. Install the insert (2) into the tapped hole by hand only.




Important: If the insert will not thread down until the flange contacts the counterbored surface, remove the insert immediately with a screw extracting tool and inspect the tapped hole for any remaining chips and/or improper tapping.

13. Install the insert until the flange (2) of the insert contacts the counterbored surface.




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.

14. Continue to rotate the driver installation tool (1) through the insert (2).



15. Inspect the insert for proper installation into the tapped hole. A properly installed insert (1) will be either flush or slightly below flush with the surface of the base material (2).



16. Any installed insert that restricts or blocks an oil or engine coolant passage (3) will need to have the oil or engine coolant passage drilled out (4) to the original size of the oil or engine coolant passage. After drilling the restriction or blockage, clean out any chips and thread the installation driver tool through the insert again to remove any burrs caused by the drilling of the oil or engine coolant passage.

Recessed Thread Repair

Caution: Wear safety glasses in order to avoid eye damage.

Important: 

•	Do NOT remove the original stop collar from a counterbore drill.

When installed to the proper depth, the flange of the insert (1) will be seated against the counterbore (2) of the drilled/tapped hole.

1. Install a stop collar (2) on the counterbore drill (1), if required.




Important: 

•	During the drilling process, it is necessary to repeatedly remove the drill and clean chips from the hole and the flutes of the drill.

•	Drill the hole until the stop collar contacts the surface of the base material.

2. Drill out the threads of the damaged hole.




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

3. Using compressed air, clean out any chips.




Important: 

•	During the tapping process, it is necessary to repeatedly remove the tap and clean chips from the hole and the flutes of the tap.

•	Ensure the tap has created full threads at least to the depth equal to the insert length.

4. Using a suitable tapping wrench, tap the threads of the drilled hole by hand only.




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

5. Using compressed air, clean out any chips.



6. Spray cleaner GM P/N 12346139, GM P/N 12377981 (Canadian P/N 10953463) or equivalent into the tapped hole.




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

7. Using compressed air, clean out any chips.




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

8. Lubricate the threads of the driver installation tool (2) with the driver oil J 42385-110 (1).



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



10. Apply threadlock sealant GM P/N 12345493, (Canadian P/N 10953488), J 42385-109, LOCTITE 277® or equivalent (1) to the insert OD threads (2).



11. Install the insert (2) into the tapped hole by hand only.




Important: If the insert will not thread down until the flange contacts the counterbored surface remove the insert immediately with a screw extracting tool and inspect the tapped hole for any remaining chips and/or improper tapping.

12. Install the insert until the flange (2) of the insert contacts the counterbored surface.




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.

13. Continue to rotate the driver installation tool (1) through the insert (2).



14. Inspect the insert (1) for proper installation (2) into the tapped hole.



15. Any installed insert that restricts or blocks an oil or engine coolant passage (3) will need to have the oil or engine coolant passage drilled out (4) to the original size of the oil or engine coolant passage. After drilling the restriction or blockage, clean out any chips and thread the installation driver tool through the insert again to remove any burrs caused by the drilling of the oil or engine coolant passage.

Tapered Pipe Thread Repair

The thread repair insert for tapered pipe threads is coated with a clear silver zinc coating.

Caution: Wear safety glasses in order to avoid eye damage.

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

When installed to the proper depth, the flange (1) of the insert will be seated against surface (2) of the base material of the drilled/tapped hole.

Important: 

•	During the drilling process, it is necessary to repeatedly remove the drill and clean chips from the hole and the flutes of the drill.

•	Drill the hole until the stop collar contacts the surface of the base material.

1. Drill out the threads of the damaged hole.




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

2. Using compressed air, clean out any chips.




Important: 

•	During the tapping process, it is necessary to repeatedly remove the tap and clean chips from the hole and the flutes of the tap.

•	Ensure the tap has created full threads at least to the depth equal to the insert length.

3. Using a suitable tapping wrench, tap the threads of the drilled hole by hand only.



4. Tap the drilled hole until the threads at the top of the tap (2) are down to the surface of the base material.




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

5. Using compressed air, clean out any chips.



6. Spray cleaner GM P/N 12346139, GM P/N 12377981 (Canadian P/N 10953463) or equivalent into the tapped hole.




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

7. Using compressed air, clean out any chips.




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

8. Lubricate the threads of the driver installation tool (2) with the driver oil J 42385-110 (1).



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



10. Apply threadlock sealant GM P/N 12345493, (Canadian P/N 10953488), J 42385-109, LOCTITE 277® or equivalent (1) to the insert OD threads (2).



11. Install the insert (2) into the tapped hole by hand only.




Important: If the insert will not thread down until the flange contacts the surface of the base material remove the insert immediately with a screw extracting tool and inspect the tapped hole for any remaining chips and/or improper tapping.

12. Install the insert until the flange (2) of the insert contacts the surface of the base material.




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.

13. Continue to rotate the driver installation tool (1) until the top of the threaded section (2) is level with the top of the insert (3).



14. Inspect the insert (1) for proper installation (2) into the tapped hole.



15. Any installed insert that restricts or blocks an oil or engine coolant passage (3) will need to have the oil or engine coolant passage drilled out (4) to the original size of the oil or engine coolant passage. After drilling the restriction or blockage, clean out any chips and thread the installation driver tool through the insert again to remove any burrs caused by the drilling of the oil or engine coolant passage.

Cylinder Head Bolt Hole Thread Repair

Important: Verify the depth of the cylinder head bolt hole and the pitch of the cylinder head bolt threads. Measure the depth from the deck surface of the block to the bottom of the cylinder head hole. All cylinder head holes should use only one of the bushings. Never use both bushings to repair a block.

With M11 bolts with a 1.5 mm pitch:

Inboard Bolt Holes

Caution: Wear safety glasses in order to avoid eye damage.

Important: 

•	The use of a cutting type fluid GM P/N 1052864, (Canadian P/N 992881), WD 40® or equivalent is recommended when performing the drilling, counterboring and tapping procedures.

When installed to the proper depth, the flange of the insert will be seated against the counterbore of the drilled/tapped hole.

1. Position the fixture plate (3) with the bushing (1) installed over the cylinder head bolt hole to be repaired (4).
2. Loosely install the fixture plate bolts (2) into the remaining cylinder head bolt holes.



3. Position the alignment pin (1) through the bushing and into the cylinder head bolt hole.
4. With the alignment pin in the desired cylinder head bolt hole, tighten the fixture retaining bolts (2).
5. Remove the alignment pin (1) from the cylinder head bolt hole.



6. Install the stop collar (2) onto the drill (1).




Important: 

•	During the drilling process, it is necessary to repeatedly remove the drill and clean chips from the hole and the flutes of the drill.

•	Drill the hole until the stop collar contacts the top of the drill bushing.

7. Drill out the threads of the damaged hole.




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

8. Using compressed air, clean out any chips.




Important: 

•	During the tapping process, it is necessary to repeatedly remove the tap and clean chips from the hole and the flutes of the tap.

•	Ensure the tap has created full threads at least to the depth equal to the insert length.

9. Using a suitable tapping wrench, tap the threads of the drilled hole by hand only.



10. In order to tap the new threads for the insert to the proper depth, rotate the tap into the cylinder head bolt hole until the first mark (1) on the tap aligns with the top of the drill bushing (3).




Important: Remove the fixture plate prior to installing the insert with the installer tool.

11. Remove the fixture plate bolts (2).
12. Remove the fixture plate (3) and bushing (1).




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

13. Using compressed air, clean out any chips.



14. Spray cleaner GM P/N 12346139, GM P/N 12377981 (Canadian P/N 10953463) or equivalent into the tapped hole.




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

15. Using compressed air, clean out any chips.




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

16. Lubricate the threads of the driver installation tool (2) with the driver oil J 42385-110 (1).



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



18. Apply threadlock sealant GM P/N 12345493, (Canadian P/N 10953488), J 42385-109, LOCTITE 277®, or equivalent (1) to the insert OD threads (2).



19. Install the insert and installation driver (1) into the tapped hole by hand only.
20. Start the insert into the threaded hole.

Important: If the insert will not thread down until the flange contacts the counterbored surface remove the insert immediately with a screw extracting tool and inspect the tapped hole for any remaining chips and/or improper tapping.

21. Install the insert until the flange of the insert contacts the counterbored surface.

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. Continue to rotate the driver installation tool through the insert.
23. Inspect the insert for proper installation into the tapped hole.

Outboard Bolt Holes

Caution: Wear safety glasses in order to avoid eye damage.

Important: 

•	The use of a cutting type fluid GM P/N 1052864, (Canadian P/N 992881), WD 40® or equivalent is recommended when performing the drilling, counterboring and tapping procedures.

When installed to the proper depth, the flange of the insert will be seated against the counterbore of the drilled/tapped hole.

1. Position the fixture plate (3) with the bushing (2) installed over the cylinder head bolt hole to be repaired (4).
2. Loosely install the fixture plate bolts (1) into the remaining cylinder head bolt holes.



3. Position the alignment pin (1) through the bushing and into the cylinder head bolt hole.
4. With the alignment pin in the desired cylinder head bolt hole, tighten the fixture retaining bolts (2).
5. Remove the alignment pin (1) from the cylinder head bolt hole.




Important: 

•	During the drilling process, it is necessary to repeatedly remove the drill and clean chips from the hole and the flutes of the drill.

•	Drill the hole until the stop collar contacts the top of the drill bushing.

6. Drill out the threads of the damaged hole.




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

7. Using compressed air, clean out any chips.




Important: 

•	During the tapping process, it is necessary to repeatedly remove the tap and clean chips from the hole and the flutes of the tap.

•	Ensure the tap has created full threads at least to the depth equal to the insert length.

8. Using a suitable tapping wrench, tap the threads of the drilled hole by hand only.



9. In order to tap the new threads for the insert to the proper depth, rotate the tap into the cylinder head bolt hole until the second mark (1) on the tap aligns with the top of the drill bushing (3).




Important: Remove the fixture plate prior to installing the insert with the installer tool.

10. Remove the fixture plate bolts (1).
11. Remove the fixture plate (3) and bushing.




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

12. Using compressed air, clean out any chips.



13. Spray cleaner GM P/N 12346139, GM P/N 12377981 (Canadian P/N 10953463) or equivalent into the tapped hole.




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

14. Using compressed air, clean out any chips.




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

15. Lubricate the threads of the driver installation tool (2) with the driver oil J 42385-110 (1).



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



17. Apply threadlock sealant GM P/N 12345493, (Canadian P/N 10953488), J 42385-109, LOCTITE 277® or equivalent (1) to the insert OD threads (2).



18. Install the insert and installation driver (1) into the tapped hole by hand only.
19. Start the insert into the threaded hole.

Important: If the insert will not thread down until the flange contacts the counterbored surface remove the insert immediately with a screw extracting tool and inspect the tapped hole for any remaining chips and/or improper tapping.

20. Install the insert until the flange of the insert contacts the counterbored surface.

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.

21. Continue to rotate the driver installation tool through the insert.
22. Inspect the insert for proper installation into the tapped hole.

Crankshaft Main Bolt Hole Thread Repair

Tools Required

J-42385-500 Thread Repair Kit

Important: 

•	Do NOT remove the fixture plate prior to installing the insert with the installation driver. The fixture plate remains in position throughout the thread repair process.

The crankshaft main bearing bolt hole thread repair kit J-42385-500 components consist of the following:

Caution: Wear safety glasses in order to avoid eye damage.

Important: 

•	The use of a cutting type fluid GM P/N 1052864, (Canadian P/N 992881), WD 40® or equivalent is recommended when performing the drilling, counterboring and tapping procedures.

When installed to the proper depth, the flange of the insert will be seated against the counterbore of the drilled/tapped hole.

1. Position the fixture plate (3) with the bushing (2), installed over the crankshaft main cap bolt hole to be repaired.
2. Loosely install the fixture plate bolts (1) into the remaining crankshaft main cap bolt holes.



3. Position the alignment pin (1) through the bushing and into the crankshaft main cap bolt hole.
4. With the alignment pin in the desired crankshaft main cap bolt hole, tighten the fixture retaining bolts (2).
5. Remove the alignment pin (1) from the crankshaft main cap bolt hole.




Important: 

•	During the drilling process, it is necessary to repeatedly remove the drill and clean chips from the hole and the flutes of the drill.

•	Drill the crankshaft main bolt hole until the mark (1) on the drill aligns with the top of the drill bushing (2).

6. Drill out the threads of the damaged hole.




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

7. Using compressed air, clean out any chips.




Important: 

•	Do not remove the fixture plate, ensure the fixture plate is installed during the machining and installation processes of the insert.

•	During the tapping process, it is necessary to repeatedly remove the tap and clean chips from the hole and the flutes of the tap.

•	Ensure the tap has created full threads at least to the depth equal to the insert length.

8. Using a suitable tapping wrench, tap the threads of the drilled hole by hand only.



9. In order to tap the new threads for the insert to the proper depth, rotate the tap into the crankshaft main cap bolt hole until the mark (3) on the tap aligns with the top of the drill bushing (2).




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

10. Using compressed air, clean out any chips.



11. Spray cleaner GM P/N 12346139, GM P/N 12377981 (Canadian P/N 10953463) or equivalent into the tapped hole.




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

12. Using compressed air, clean out any chips.




Important: 

•	Do not remove the fixture plate, ensure the fixture plate is installed during the installation process of the insert.

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

13. Lubricate the threads of the driver installation tool (2) with the driver oil J 42385-110 (1).



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



15. Apply threadlock sealant GM P/N 12345493, (Canadian P/N 10953488), J 42385-109, LOCTITE 277® or equivalent (1) to the insert OD threads (2).



16. Install the insert and installation driver into the tapped hole by hand only.
17. Start the insert into the threaded hole.

Important: If the insert will not thread down until the flange contacts the counterbored surface remove the insert immediately with a screw extracting tool and inspect the tapped hole for any remaining chips and/or improper tapping.

18. Install the insert until the flange of the insert contacts the counterbored surface.

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.

19. Continue to rotate the driver installation tool through the insert.



20. Rotate the driver installation tool until the mark (3) on the driver installation tool aligns with the top of the drill bushing (2).
21. Inspect the insert for proper installation into the tapped hole.



22. Remove the fixture plate bolts (1).
23. Remove the fixture plate (3) and bushing (2).