This revised recommended practice improves the testing conditions for retorque. The number of retorques was reduced back to the original five times since data presented showed the loss of tension occurs in the first five retorques and is relatively stable after five retorques. The retorque testing causes heat to be generated which is not representative of reinstallation of nuts in the field. Data was submitted that following the original procedure for the first four retorques of 1 minute dwell and then allowing the nut body to cool to 60 to 80 °F for the 5th retorque gave the same results as waiting for cool down after each retorque. The lubrication which was optional is now standardized. The temperature measurement location of the middle of the hex of the nut was found to be the best location and also easy to measure. It is shown in Figure 2. We added the M18 ball seat nut to proof load Table 1 as it is used in medium trucks.
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