Wisconsin Joe

No. It has to bounce.

I do my own, using the "jackstands & strings" method.
I use ramps to get under to make adjustments.

I replaced a tie rod end a couple years ago, and despite my best efforts to make the distance between the inner and the spindle as close to identical as I could, it was way off.

So i got it close (knowing the suspension wasn't fully settled) to preserve the tires. Drove it, checked it, up on ramps to adjust. Repeat until the suspension settled (checking ride height at the fender until it stabilized).

I don't claim it is perfect, but I can get within 1/32.

Front tires are wearing normally.

dr bob

The key to using the pull-down method is knowing in advance what the ride height will be when settled. Without that number, you can tell the tech where the height needs to be during adjustment. Then it's your responsibility to get the car to "settle" to that height.

There is absolutely no magic to getting the alignment correct, just takes some diligence and accurate ways to measure each parameter.


For most 928's at this point in their wear lives, it's probably a Good Idea to have a qualified front-end tech inspect the car before alignment anyway. As much as we love to think that the car "drives fine" and therefore has no worn suspension and steering pieces, the reality is that the pieces do wear, and do need to be replaced after a certain amount of wear. Another set of professional eyes will spot things we might be in denial about.

Anyway... Measure the ride height of your car regularly, and write the numbers in the car's maintenance log book. You'll be able to monitor the sag that happens over time, and correct for it before your tires show uneven wear. You'll have the numbers for the alignment tech too, so he knows where to put the car to get the alignment correct.

Rich9928p

The last thing about a 928 alignment is tighten the rear camber bolts to the 140 fl-lb spec. Very few alignment places seem to use torque wrenches, and 140 is a bit more than you might assume those bolts would need so it's good to address this when talking with them.

Tom in Austin is 100% correct. I had my S4 aligned by an independent Porsche shop (later found out their rack was out of service and they took it to another shop). Some few thousand miles later I heard nasty cracking noises when I'd turn the wheel at low speeds ... I couldn't imagine what could cause this. I had Dan at Exotic Motorwerks check out the front end. He found the bolts were under torqued. Now I probably need another alignment.

Rich
928 OC Membership Chairman
1993 928 GTS Cover Girl
1987 928 S4
1979 928 5-speed rescue
1979 928 Euro 5-liter track beast

Jherriott

OK, hoping this doesn't sound too dumb; since I didn't measure the ride height before I did the Steering Rack, should I just get the alignment done toe-and-go method to save my tires? Then a few months down the road, after paying attention to ride height, get a proper no-lift alignment done?

Jase.

dr bob

Toe is closely related to ride height, so "toe and go" won't leave you in good shape to preserve the tires. Your car was raised for the work. Now decide what height you'd like the car to ride at. For the front, the lowest you want to go is 170mm, measured from the floor to the pad in the lower control arm's rear support bushing. The factory setting is 190mm, and there's a total of 20mm sag allowance in the factory spec. That was a limit defined for warranty services more than for geometry. Meanwhile, owners get used to seeing the car low (sagged), and start to feel that the original numbers make the car look too high.

So decide what height you want the car aligned at, and have the shop pull the front end down to that height. Or, go someplace that will re-align after you've driven the car a hundred miles or so, after the suspension has relaxed back to it's normal height, whatever that ends up being. At the final alignment, it's extremely important that the tech not lift the car at all before or during the alignment. If he does, you get to repeat the 100-mile settling period and do it again.

The penalty for failing to follow this guidance is scrubbing the inside rib off the front tires. You can cord a set of otherwise-fabulous front tires in a few hundred miles of driving with droop-induced toe-out. It's an expensive lesson.

Jherriott

Awesome dr bob. And thanks again for all the replies to everyone. Much learned today for this newb. I'll be going next week, so I'm going to hunt around for a shop that cares

Jase.

FredR

Jason,

As you can see from some very well informed posts above, some of our "better minds" are not entirely aligned - pardon the pun. This is not too surprising given the variables in play here however, make no mistake, they all agree on the consequences of getting it wrong.

Not sure what you know and what you do not so I will try to demystify things for you a little bit based on my experience and bearing in mind that I have had many visits to the alignment shop whilst finding optimal alignments for my specific needs.

First thing to remember is that settlement of the front end is problematic but equally I suspect that different examples with suspension systems in different states of wear will show different settlement characteristics- "tighter" examples [i.e. better condition] taking longer to settle so there is no such thing as "one size fits all" - just a conservative recommendation to cover most settlement possibilities.

What I found on my 928's is that settlement is not linear and most settlement takes place quite quickly, i.e. within about 15km but I cannot say with any certainty when all settlement has taken place.

To settle the motor I do some rapid stops from about 100 mph and I also take the car around a road I know that has a lot of speed bumps and do a few km on that. As to whether it accelerates matters all I can say is that it seems to work for me.

As the system settles you have to understand that the camber negative reading will increase [more negative] and the toe setting will decrease. If you suspect the car is not fully settled you can set values in anticipation of subsequent change, toe being the most critical element. The stock alignment covers a range of acceptable values so you can ask the shop to dial in a safe value that will be expected to change. Just remember that for tire scrub, it is toe that is critical and as Bob says, if the system toes out good tyres can be killed in relatively little time.

Thus if you follow a few simple rules you will eliminate most of the variables:
1. Make sure the car has been driven and has settled to some degree or other.
2. Supervise the alignment start to finish and ensure no one lifts the vehicle off the deck.
3. I always use the Hunter machine and nothing else.
4. Try to ensure the tech dials in the numbers you want. The computer programme gives a range of values and some techs will stop when they see the values are in the "green zone" [the Hunter has traffic lights to show acceptable values for your specific model/year].
5. Insist on having identical values on both sides. A little variance is unavoidable but with due attention [that takes time] values can be very evenly balanced. The nature of the beast is that as one adjustment is made it can alter another parameter so it is a bit of an iterative process.
6. Start from the rear of the car, set rear camber and then rear toe in. For rear toe I select a mid range value. The rear end settles quickly so not usually an issue. The torque value of 140 ft lbs for the camber adjuster- insist on seeing this personally [I do it myself with my torque wrench after the tech says it is tight].
7. On the front I usually set the front camber adjust the toe, then the castor, and it often takes a few iterations until I get the balance I want. Then I torque the camber, the castor and finally check the toe before locking that. If you feel the car may not be fully settled you can dial in more toe up to the max permitted knowing it will come down with full settlement and this is safer than too little toe.
8. For castor you should note that earlier S4's have a recommended castor of 4 degrees, later models use 5 degrees and this can be used on the earlier S4's [according to Porsche] but the Hunter does not show this.
9. At this point it is also good to record where the ride height sits for future reference. You can take an approximate measure by recording numbers from the wheel arch to the deck but using the reference points is preferred.

If the above are done correctly then you may still need to make further adjustments but in all probability you will not be too far out when full settlement takes place. Now drive about 100 miles and check where the ride height sits. If you do experience noticeable further settlement take it back to the alignment shop and ask them to recheck the setting. Perhaps you can negotiate a good rate with them to do this check irrespective of whether it settles further or not.

Alternatively, once you have done the 100 miles you can also do a visual check. Although it may sound strange, I reckon I can eyeball whether my front end has a positive toe in. I stand about 2m behind the car, crouch down onto one knee, shut one eye, and move my head side to side until I cannot see the front edge of the front wheel. If you have a positive toe you should be able to sense your view point is wider than where the wheel sits- do this both sides. Better still, you can also mount a laser, project the beam onto a wall, mark the impact point and do the same on the other side then measure the distance between the marks. This should enable you to understand whether you have a positive or a negative toe. With experience and a bit more science you can even adjust the toe reasonably accurately this way.

With my bigger front wheels I require front toe to be minimal to reduce steering effort and assist turn in so I always set it up on the Hunter. At the moment I have just replaced the lower ball joints and eyeballed everything putting the adjusters back to where they were. I know it will be out a little bit, I did a couple of iterations on the toe and it now seems to be running reasonably well this crude way. However, I also know my tires are at the end of their useful life due to age hardening and will do the Hunter alignment after fitting new tires and allowing the car to settle. the current crude alignment should be OK to avoid any accelerated new tyre wear during settlement.

Trust the above helpful to you- others may disagree with me.

Rgds

Fred

Jherriott

^^ Much obliged Fred R. Lots of good points there to go over with the shop. Also, when I said the shop has a scissor type lift thingy with rotating discs under the wheels... apparently, in reality that is called a Hunter Machine. See what I meant when I said newb?

Jase.

FredR

We were all new to the game at some stage! I have no idea how many types of such machine are available over there but the ones we have here [and not too many of them] are made by Hunter as are the wheel fitting/balancing machines and they work well.

The rotating discs are friction less pads intended to allow small adjustments with little to no hysteresis. Indeed they are so sensitive that if located in a building with open sides a good wind can change the readings! The one I use is well sheltered!

Rgds

Fred