The PORSCHE 928 has very unique suspension bushings compared to other cars. If you jack up a 928 and let the wheels hang down, the bushings immediately take a "set". When you lower the car back down on its tires and roll the car back and forth to "settle" the suspension, the car will now sit ~1" higher than before it was jacked up. The car will now have to be driven up to 100 miles depending on how rough the roads are to settle the car back down to its proper height. The Porsche shop manual says "after a longer journey or longer operating period".

If you align the wheels with the car sitting 1" inch higher than the normal ride height, then, after settling, the front tires will have excessive toe-out and may be destroyed in less than ~1000 miles.

If you align the 928 with the car sitting 1/4" inch higher than normal, then, after settling, there will be no toe-in and the tires may be destroyed in ~2500 miles.

Normally one of the first steps in alignment is to jack the car up and check for worn and loose parts. You can do this and have the owner drive the car enough to settle the suspension and come back for the alignment. Or, you can check for worn parts with the car on its tires. CAUTION: IF you do jack the car, use the jack pads near the wheels, NOT the frame members near the center of the car, they are crumple zones and not strong enough for jacking. The The 928 suspension is very robust and ball joints wear very little if the boots are intact.. Usually the first parts to wear and need replacement are the inner tie rod ends. Put the steering rack centering bolt in and shake the wheels to check. If one is bad, then it is best to replace both the inner and outer tie rod ends on both sides. On older, high mileage cars, the upper control arm inner bushings wear. These bushings are now available from the 928 vendors.

If you can't do alignment without lifting the car to accommodate your alignment equipment, then you should probably decline the job. It is not worth the hassle and you probably won't make much profit if the front tires are destroyed and you have a very unhappy customer.

If you still want to do the alignment after lifting, there is a PORSCHE procedure to do this. It involves pulling the front of the car down by 60-70 mm and hold for 1 minute. After releasing, bounce front and rear approximately 25 mm a few times. The transport lugs or stabilizer can be used to pull the car down. If you plan to do this, I suggest that you check the ride height before lifting and then check before aligning to be sure that the measurements are the same. The easiest way to check ride height is to measure from the floor or turntable to the lip on the fender through the center of the wheel before and after jacking. The ride height during alignment MUST be the same as the ride height before jacking. If the ride height is near factory specifications, this measurement should be about 27" for the front and about 24.5" for the rear. Many cars are lower. If the measurements vary much from factory specifications, you might want to discuss adjusting the ride height with the owner.

The rear suspension alignment is not affected as much by this lack of settling but will affect the front caster slightly if the rear is high and the front normal.