When using the Matra 517 tool, make sure that this tool is pressed flat against the wheel nut. Failure to do so may result in bent or broken pins when excessive force is required to loosen the wheel nut. The tool can be pressed against the wheel nut by means of a threaded rod with washers and nuts that is mounted through the tool and the wheel hub. If the pitch of the threaded rod is the same as that of the wheel nut (1.5 mm), the tool will still be pressed against the wheel nut when loosening. Do not overtighten the nuts on the threaded rod. Do not use a hammer on the pin spanner key, as this may break the 4 pins. Instead, use a metal tube to extend the pin spanner's arm to provide more force if needed.