And almost every one of those adjustments affects one or more of the others. You could tear your hair out for a week trying to get the thing the way you want it, and it would still be wrong. For example, if the car pulls to the right, it means that there is more weight on the left front and the right rear tires than there is on the other corners. This is not the case with the run-of-the-mill minivan you see at Walmart, which is lopsided for other reasons having nothing to do with precision handling, but we won't get into that subject just now.
I ordered a batch of rubber bushings for the front anti-sway bar, since they appear to be the cause of the clunk, plus a set of 'bump steer' spacers to accommodate the too-low front of the car. The spacers lift the steering rack so that the tie rods are once again level after having been lowered. I'm not especially interested in raising the car back to 100% stock in the height department.
Anyway, lifting the steering rack will affect the negative camber and toe, once again. Maybe it will actually put the alignment almost right, but it won't fix the steering wheel vibration, nor the drift of the car to the right which likely is a corner balance issue. The mechanics you see here are competent and have aligned a number of Porsche 911s, so we'll see if they have a comprehension of all the subtleties in the bigger picture.
Naturally you have been wondering why there are so many adjustments to be made to the suspension of an older Porsche like mine - or yours. Today's Porsche cars may have even more complex adjustments; I don't know, but if so, they are there for somewhat different reasons. What I do know is that when my car was built, in November of 1973, it was not produced on a modern production line, such as those pioneered by Henry Ford in 1913 - a century ago. Each Porsche was installed on a sort of large wheelbarrow device that allowed it to be moved along when it was ready for the next phase of its construction. I guess this was a 'production line' of a primitive sort, but it was not as smooth as the one Ford had in operation 60 years earlier, which manufactured cars in large numbers.
Porsches the age of mine were among the last of the handmade cars constructed by any surviving manufacturer to build cars in significant quantities. Each body was assembled using parts that had been stamped out, as is normal. They were then welded and soldered together without the same precision, identical alignment of typical modern cars built in huge numbers. Therefore, every body is different to a degree, and it is easy to see this if you compare a number of examples of this era - you can see hammer marks from the process of convincing various pieces to fit together. As well, one person might have assembled a transmission, or engine, and when it was finished it went into a certain car. There weren't dozens of people involved; these cars were pretty much hand built.
|1974 production line. Notice all the workers and the frantic pace involved.|
Naturally, this makes for complication 40 years after the car was built. Some components might have been replaced, but not others. Possibly a previous owner made changes to suit his interests, and he might have botched the job. Parts will have been damaged from the years of vigorous use the cars have endured. I found evidence of vigorous use in my car when I removed the gas pedal. It was bent into a curve from having been mashed hard to the floor repeatedly over time. Also, other abuse was possible, even expertly repaired and concealed accident damage. All of this makes solving the issues my car now suffers a test of resolve and creativity - as well it is necessary to read competent books on the subject.
Continuing this story later, all the parts I ordered arrived and have been installed, and so the wheels were aligned again. I think. Every movement up or down of the car (i.e. push up on the bumper, or pull down while it is on the alignment rack) changes all the settings. So, when is it correct? Everything will change as you bounce down the road, therefore, there is no apparent absolute alignment, except for momentary serendipity when you hit the right bump or slope in the pavement. I guess you get it in the ballpark. That, or I find a more experienced Porsche aligner.