# Optional Procedure - Break Loose Check

In order to determine the retained load in a tensioned bolt it is possible to re-tension the bolt, and during the pressurisation sequence constantly monitor for the pressure point that the bolted joint hexagon or round nut comes loose.

It is normal to use a single bolt tensioner when completing a break loose check.

1. Assemble the tensioner on the pre-tensioned bolt, see also Installation of the Aero WTB Tool

2. Connect the tensioner to the tensioning pump using a single Atlas Copco hydraulic link hose.

3. Insert the torque ratchet handle into the square drive of the nut rotating gearbox.

4. Start the tensioning pump unit. The pump will start to run and pressure will build up slowly in the system. As the pressure builds, constantly apply a hand torque to the torque ratchet wrench in an anti clockwise direction. Constantly monitor for the pressure that the nut rotating gearbox shaft begins to freely rotate. This free rotation of the gearbox shaft in an anti-clockwise direction indicates that the tensioner has exceeded the load that was originally retained in the bolt. Immediately stop the pump unit and make note of the break loose pressure.

5. Once the break loose pressure has been noted, continue to pressurise the tensioner to the original specified working pressure.

6. When the original specified pressure is achieved, stop the pump, the pressure should hold steady.

7. Tighten the nuts down against the joint face using the square drive on the gearbox shaft. Turn the shaft clockwise to tighten.

   The applied torque must not exceed 30 Nm.

8. Slowly release the hydraulic pressure to zero; The tensioners are fitted with an automatic reset mechanism, which allows the pistons to retract after depressurisation. Monitor the puller protruding out of the top face of the tensioner. Once the pressure is released, the puller bar will begin to withdraw into the top face of the tensioner. Only continue once the pullers are flush with the top face of the tensioner.

9. To ensure a good tightening result, repeat the Tensioning Operation section Steps 6 to 8.

## Converting Break Loose Pressure to Break Loose Load

Multiply the Break Loose Pressure by the Hydraulic Pressure Area of the tensioner to determine achieved bolt break loose load.

Example: Using M48 WTB Tensioner HTT.11451.000, Tensioner Pressure Area = 14.025 In² and Break Loose Pressure = 10000 psi

Break Loose Load = Break Loose Pressure X Tensioner Hydraulic Pressure Area

Break Loose Load = Break Loose pressure X Tensioner Pressure Area = 10000 x 14.025 = 140250 lbs = 62.611 ton