Suspension & Steering
Alignment Done Right
Due to some weird trick of nature, the 928 front suspension, once raised, rides about 2 inches higher than normal. It takes around 15 to 20 miles of driving for the suspension to work its way back to normal ride height. You will see this immediately after setting the car back on all fours as the gap between the front wheel and the wheel arch will have doubled! Herein lies the problem.
Wheel alignment is sensitive to ride height, as ride height alters the values of camber, toe etc used for the alignment. Typically, an alignment shop will drive your car in, lift it up to attach its electical gizmos to your wheels and spin them to calibrate their machine. They then drop it down to do the alignment. At this point the car is riding 2 inches higher than normal. They align to factory spec and send you on your merry way. Unfortunately, 20 miles down the road your car has settled and the alignment is now way out. The most common symptom is that you will wear the inside edges of your front tires very quickly. Like within a couple of thousand miles. The car will also not handle as well as its design allows and may tramline or feel unstable at speed. No attributes you want to pay good money for.
So, the solution is to find an alignment shop that will calibrate the wheel sensors by rolling the car backward rather than lifting it and spinning the wheels. Some shops will, some have trouble adjusting their paradigm! Other list members may be able to assist in suggesting a 928-friendly shop in your area.
Thanks to everyone who urged me to only get my front wheels aligned by *not* lifting the front. I had the alignment done a couple days ago and asked the mechanic about attaching the sensors and rolling the car back rather than lifting by the outer edge of the lower control arms as he had done before. He thought that should work just fine so he did the alignment by that method. He said it was a lot quicker and less trouble for him as well as providing a better alignment. He has a "Hunter" brand machine.
The car drives very good in all respects with no, or very little, tendency to follow road ruts. I'm near Portland, Oregon, and the shop is at 902 N. Lombard (Tire Factory store).
I also set the ride height to factory specs., so that likely helped too. I had to raise the front adjusters 9 turns and the rears 3 turns. Kinda tedious but worth it.
Louis Ott - MY '40
Had an alignment done a few weeks ago because the car was pulling left.
After alignment it still pulled left and steering was not centred. Had it redone a week later by same place - steering now centred again, but car still pulling left. Went back a third time - alignment guy says I think I know what it is, re-aligns and it comes out spot-on.
After my final test drive I asked him what the problem was: Turns out that the back wheels weren't floating on the first two alignments and the guy then pulled the stop-pins out on the floating rear slides for the third alignment.
Moral is that car must be on slip plates on all 4 corners to do a successful front-wheel alignment.
Probably common knowledge to many people, but worth checking that your alignment shop does this right.
Jonathan M Rackowe
JMR Technical Services, London, UK
1991 928 GT, Manual, Baltic Blue/Linen Leather
After 6 alignments on my 84 in 2 yrs, I finally figured out what it takes to get a good one. I took my own ratchet tie downs to the shop. Had the tech (total doubting Thomas) measure pre-lifting ride height, 25 5/8, then lifted the car, checked all components, did the bounce many times. Car never came below 27". I then pulled it down as per the manual. Boom, there we were. Let me tell you, I opened the dudes eyes to the real way to do alignments...
We then left town for a 800 mile trip to Atlanta, and the car never tracked so good. The only problem we found is that the speedometer is about 5 mph off. Well, that is what some Barney Fife Virginia trooper was kind enough to point out to us. Ouch, that makes 4 tickets in 2.5 weeks.
Don't fret this alignment stuff. It really is easy. Show your mechanic pre and post measurements, done before his eyes. And take your own tie downs so he can't claim ignorance.
Just went down to Evergreen Tire and Wheel to have my steering wheel centered. (it was about 10 degrees off) after they did the alignment for the body shop. the man to ask for is Fred. not only has Fred done lots of 928's (mine included and it turned out great) but their alignment rack does NOT lift the car. its called a Visualign machine and it only mounts reflectors on the wheels, not the whole laser unit. in fact, this machine uses LED's and not lasers, that are mounted to posts that are bolted to the concrete floor. its very impressive. its so sesitive that my cooling fans running showed up on the display! very accurate. only requires that the car be rolled back about 6 inches, then forward again. NO LIFTING! its costs about $90-$100 which is cheap compared to what some places charge. FINALLY someone in the south Puget Sound area that can do it RIGHT! highly recommended. they are located at 38th st. and South Tacoma Way, just down the road from Austin's ProMax where the Dyno Day was/will be. Just make sure to ask that Fred does it. take care all.
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