How to Check Helicoil Threads
- 1). Position yourself so you can have a straight head-on view of the helicoil bolt that you will be extracting. If the helicoil bolt belongs to an automotive head, intake or exhaust manifold, place it on a flat and level workbench. For a smaller piece, place the object in a bench vise and firmly clamp it. A downward or 45-degree angle will allow you the best leverage.
- 2). Spray some penetrating oil on the helicoil bolt and let it soak for approximately 15 minutes. Use a socket and ratchet to loosen and remove the bolt, but do so slowly. Make sure you use the correct rotation for removal -- most bolts turn counterclockwise for removal.
- 3). Watch the bolt as it exits the hole. The helicoil insert spring should not come up with the bolt, nor exit the hole with any protrusion. It should stay firmly embedded inside. Examine the end tapers of the bolt threads for stripping and nicks. If any striations, cuts or nicks appear, it indicates debris or shavings have been left in the hole. Use a compressor, attached to a nozzle gun, to blow out any shaving remnants inside the hole.
- 4). Look inside the bolthole. There should be no rust adhering to the helicoil threads. The threads should appear sharp and well defined, with no mashed edges. If the helicoil appears damaged, or has unscrewed with the bolt, use an extractor from a helicoil kit to remove the old helicoil insert. Blow out the bolthole with compressed air. Size up the old helicoil insert with a new one from the kit, then attach it to the installation shank. Attach the T handle on the shank and turn the new helicoil insert into the bolthole.
- 5). Turn the helicoil insert into the hole past the top threads, by a depth of one thread. Place a punch in the hole over the break-off tang on the end of the helicoil spring. Tap the punch with a hammer, to break the tang. Use compressed air to force the tang out of the bolthole with air pressure.
- 6). Insert the bolt in the hole and screw it in with a socket and wrench until you meet resistance. Refer to your owner's manual for the proper torque, in foot-pounds, required for the bolt. Use a torque wrench to tighten the bolt to manufacture's specifications.
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