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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1219 (Engine Mechanical - 4.2L 6-Cylinder (Unit Repair)) >> Repair Instructions >> Thread Repair >> Notes

Thread Repair: Notes

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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 tool kit J 42385-400 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 J 43965 may also be necessary to drive the thread repair tooling dependent on access to the hole being repaired.

Fig 1: Drill And Thread Repair Kit
G01706580Courtesy of GENERAL MOTORS CORP.

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

Fig 2: Drilling, Counterboring And Tapping Of Hole
G01706581Courtesy of GENERAL MOTORS CORP.

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

Fig 3: Machining Perpendicular To Surface Of Base Material
G01706582Courtesy of GENERAL MOTORS CORP.