1) Position the vehicle carefully, taking account of its type (front-wheel drive, van etc), any additional load carried and the configuration of the lift (see here). Failure to do so may place the centre of gravity of the vehicle away from the columns giving an uneven weight distribution.
2) The horizontal and vertical position of the pick-up plates then need to be adjusted, to ensure they will make full contact with the jacking points and support the vehicle securely. It is good practice to partially raise the vehicle (about a metre off the ground) and, by observation and rocking the vehicle, check that:
- the pads are correctly located;
- the vehicle is not being accidentally supported on the lifting arms instead of the lifting pads;
- the arm-locking system has engaged fully on both sets of arms;
- the vehicle is stable; and
- the vehicle is being lifted parallel to the ground.
Even if a vehicle is properly supported on the pads, removal of heavy items once the vehicle is elevated may significantly alter the centre of gravity and individual pad loading. If the force exerted on any individual pad becomes too great or too light, and there is any free play in the arms or the arm-locking mechanism, the pad may either be ‘squeezed’ out or else be free to move horizontally. Where the movement is sufficient, the vehicle will no longer be fully supported (and is, essentially, balanced on just two or three of the pads). Any subsequent vertical load (eg torque generated by the use of tool) could cause the vehicle to fall from the lift. Consequently, operators should continually evaluate the need for additional supports (eg vehicle props) particularly where the combination of lift configuration and vehicle type is not ideal or where heavy items are to be removed from the raised vehicle.