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 used.
In order to exclude erroneous measurements, the following preconditions must be met before alignment and the following points should be given special attention:
Empty 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 OK (wheel-bearing play cannot be adjusted).
Tyre pressure in accordance with regulations, fairly uniform tire tread.
Quick-clamping holder with adapter (for the measured-value pickups) correctly secured to the wheels. Different procedure for vehicles (wheels) with central bolts (911 GT3 as of 2010 model)!
Use self-centring quick-clamping holders → WE1265 Porsche Quick-Clamping Unit to secure the measured-value pickups on the wheels. Any previously used quick-clamping holders that are available can also be used. Cannot be used for vehicles (wheels) with central bolts .
The self-centring quick-clamping holders are positioned centrally (with the claws first) in the center of the rim and are tautened 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. Always check the levelling surface on the wheels precisely in particular before fitting the quick-clamping holders.
Comply strictly with maintenance intervals for measuring equipment and measuring platform. If the levelling of the measuring platform or measuring station is done in-house, levelling equipment is required. A spirit level is not adequate.
Skilled handling of measuring equipment and measuring platform.
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, high-speed strength of the tires, 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. Camber values at the front axle apply for the straight-ahead position of the wheels. Steering wheel and steering gear in center position when toe is being adjusted.
Before wheel alignment values are adjusted on front and rear axles, it is recommended or required that the height adjustment be checked at the DIN empty weight. Height adjustment allows the wheel-load difference to be kept as low as possible, provided wheel-load weighing machines are available. The wheel-load difference is adjusted by changing the vehicle height within the height tolerance. The priority is to achieve the smallest possible wheel-load difference per axle from left to right. Conclusions can also be drawn about wheel alignment values in the event of any suspension alignment that becomes necessary later.
Before taking measurements and if the vehicle was previously raised or the setting was changed, quickly bounce the vehicle a few times on the rear and front axle. This is necessary in order to avoid getting incorrect measured results.
Check all wheels for clearance after adjustment and assembly work!