After collisions, technicians must check all seat belt units starting from retractors up to belt tension sensors when equipped, as well as buckles, shoulder belt position adjusters when installed, and child seat tether anchors and their hardware attachments. If a qualified technician finds no damage in assemblies that operate correctly, then new belt assemblies can stay in place. An inspection should be conducted on all seat belt assemblies that stay unused during a vehicle impact. Professional installers should replace damaged or malfunctioning assemblies. The correct method to handle the LH seat belt buckle assembly requires bolt removal before assembly installation and final tightening at 40 Nm (30 lb-ft). Take out the bolt from the center seat belt tongue assembly before installation while tightening it to 40 Nm (30 lb-ft). Tighten the bolt from the RH seat belt buckle assembly to 40 Nm (30 lb-ft) when correctly installing it into its position. Before installing, the seat belt webbing needs to be untwisted, so the installation process must go in reverse order of removal steps. Active restraint system operation requires a final check before completing installation.