General Procedure For Wheel Alignment

Perform wheel alignment using an electronic wheel alignment tester. Measurement procedures should be taken from the operating instructions for the wheel alignment tester.

In order to exclude erroneous measurements, the following preconditions must be met before alignment and the following points should be given special attention: 

• Unladen weight of vehicle according to DIN 70020, i.e. vehicle in ready-to-drive condition with full tank and including tools but without driver or additional weights.
• Ball-joint and wheel-bearing play in order (wheel-bearing play cannot be adjusted).
• Tire pressure in accordance with regulations, fairly uniform tire tread.
• Use self-centring quick-clamping holders Porsche Quick-Clamping Unit WE 1265  to secure the measured value pickups to the wheels. The self-centring quick-clamping holders are positioned centrally (with the claws first) in the center of the rim and are tighten in the rim by turning the straining ring (clockwise).
• Receiving surfaces for the quick-clamping holder on the wheels and the adapter surfaces must be clean and flat. In particular, always accurately check the levelling surface on the wheels before fitting the quick-clamping holders. Quick-clamping holder with adapter (for the measured-value pickups) correctly secured to the wheels. 
  Fig 1: Identifying Self-Centring Quick-Clamping Holder

  Courtesy of PORSCHE CARS NORTH AMERICA, INC.
• Strictly comply with maintenance intervals for measuring equipment and measuring platform. If the levelling of the measuring platform or of the measuring area is done in-house, levelling equipment is required. A spirit level is not adequate. The permissible level tolerances are: transverse front axle: max. 1.0 mm/transverse rear axle: max. 1.0 mm/longitudinal: max. 1.0 mm/diagonal: max. 1.5 mm.
• The measuring equipment and measuring platform must be handled competently.
• Sliding plates with transverse motion (rotary motion) at the rear axle are advisable.
• Observe the Technical Literature of PAG, the manufacturer of the measuring equipment and the manufacturer of the measuring platform.
• Do not treat measured values as a whole, but very critically with regard to driving dynamics, tire wear and cost/benefit effects (time required for correction of insubstantial deviations). The toe values are of decisive significance for driving dynamics and tire wear. 
• If the vehicle is measured front and rear, check and adjust the wheel alignment values at the rear axle first. The camber values at the front axle are valid if the wheels are in the straight-ahead position. The steering wheel and steering gear should be centered when adjusting the toe.
• Before wheel alignment values are adjusted at the front and rear axles, it is recommended that the vehicle height be checked at the DIN empty weight. Conclusions can then be drawn about wheel alignment values in the event of any suspension alignment that becomes necessary later.
• Calibrate the steering-angle sensor if the previous wheel alignment values (at rear and/or front axle) were changed. In each individual case (if the wheel alignment values where changed only slightly), read out the steering-angle sensor actual value first and only calibrate the steering-angle sensor if necessary.