Exam 51: Engine Sealing, Gaskets, Fastener Torque

Correct Answer:

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To get an accurate reading with a torque wrench:
1. Select one of the correct size. If 50 foot-pounds (ft.-lb) is required, use a 100 ft.-lb torque wrench.
2. Hold it at 90 degrees to the fastener being tightened.
3. Torque in three or four steps.
4. Tighten first to about one-third of the torque specification.
5. Then tighten it two-thirds.
6. The third step should be to within 10 ft.-lb of the final specification. When the last step is within 10 ft.-lb, the final torque will be more accurate.
7. The final step is to double-check all torque readings. During the recheck, if a bolt still moves it should be removed and examined for water or oil in the hole. Liquid trapped in a blind hole can cause initial resistance to torquing before it bleeds up the threads, causing the bolt to loosen. If the hole is free of liquid, replace the bolt.