Initial Wheel Alignment
Initial Wheel Alignment
02-27-2004, 01:10 AM
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Piece of cake. Here is the stuff I found from the various discussions here and varous websites. I used this after I rebuilt my front end and it worked great. Start by adusting the ride height. This is a chicken and egg problem because you have to settle the car with (opinions vary here) 20 miles of driving to get the right readout. So you probably iterate on it - get the alignment close, drive to settle, adjust the height, get the alignment close again.....
Note that caster adjustments may be different for your MY. Search this site for alignment and you will find other clever techniques.
Sage advice follows:
Before You Start:
A day or two before you plan to adjust your suspension, find the height adjuster at the bottom of each spring and spray them thoroughly with a penetrating lubricant.
To measure Ride Height: What and Where.
Front: There is a small flat-machined area on the bottom of the cast bracket that holds the rear of the Lower Control Arm, between the ribs. This pad should be 180mm +/- 10mm from the floor for new springs - you are allowed another 10mm for used springs. There should be a max difference of 10mm from left to right.
Rear: There is a small flat-machined area on the aft bottom of the large u-shaped bracket that holds the lower transverse control link (the large flat blade). This pad should be 173 +\- 10mm from the floor, with the same 10mm allowance for old springs. There should be a max difference of 10mm from left to right.
You MUST measure, jack and change, then drive the car for at least three or four miles before you re-measure
How to Change the Ride Height.
Turn the front wheels all the way left or right, lube the nut area well with a penetrating spray lubricant, and turn the nut right to raise, left to lower. You can get to the rear (also lubed) with only a little stretching. Adjust the height all the way around and re-measure. When you think that you have it right, drive the car for three or four miles and re-measure, curse and readjust.
Setting the Camber
Set the caster
Turn the caster eccentric (inboard on steel ball joints) until the ball joint is all the way back, the inner end of the ball joint carrier will now be all the way forward.
Set the camber (the top-to-bottom angle of the wheels).
You can check the camber with a 24" level. You want to have 1/32" clearance between the level and the top tire sidewall with the level plumb and touching the lower tire sidewall. The surface that the car is sitting on does impact this - either use a level area, or check the camber, turn the car around and check it again and average the readings.
The camber is adjusted by turning the eccentrics on the lower control arms. The camber eccentric is the outer one for steel ball joints.
After you measure the camber and determine that it needs adjusting, you must jack the car, re-measure the camber and adjust that camber reading enough to change your original reading to 1/32", and then drive the car enough to settle the suspension (several miles!) and recheck the camber.
The rear camber should measure about the same as the front, but is adjusted by an eccentric at the inboard end of the rear link (the transverse vertical blade).
Straightening the Wheels
Straighten the front wheels with the steering wheel. If you want to get everything really straight, pull the small plug on the front of the steering rack on the driver's side and turn the steering shaft until you can see the mark on the steering rack thru the hole. This centers your rack. Pull the steering wheel and straighten it if necessary.
Toe in
Settle the Car (Again)
Before you measure the toe-in, the suspension must be settled by driving the car several miles. You cannot settle the car by bouncing on the fender - it takes about 6-800 pounds to force the car down, and it must be held there for one minute to settle it. Will your aluminum fenders stand that?
Set up
After you get the front ride height and camber set, adjust the toe-in. Easiest way is to "string" the car, ala NASCAR. Use any four convenient objects to securely hold two strings that run beside the car, at about wheel center height and an inch or two from them, and extending a foot or more beyond the ends of the car. Measure the distance between the strings in front of and behind the car, and make these distances identical. Make the distances between each rear wheel center and its string identical. Make the distance between each front wheel center and its string identical. Check to make sure the distance between the strings is identical in front of and behind the car. Warning! The track is rarely the same front and rear, so don't use just the measurements from the wheel centers to set your string!
Setting the Toe-In
Measure the distance from the front of each tire to the string and the distance from the back of the tire to the string. Try to be very consistent on where you measure from on the tires. Do the simple math to get the difference between the front and back measurements on the front tires. Adjust the tie rods (loosen the jam nut, turn the tie rod - don't forget to tighten the jam nut when you finish) on the steering rack to get the tires almost straight ahead, with the smallest amount of toe-in (tires closer together at the front) that you can measure.
Aligning the Car
These procedures will get your alignment close enough to drive the car until you can find an alignment shop that will align your 928 WITHOUT JACKING IT UP. If your alignment shop can't or won't do the alignment without jacking the car up, find another shop.
Note that caster adjustments may be different for your MY. Search this site for alignment and you will find other clever techniques.
Sage advice follows:
Before You Start:
A day or two before you plan to adjust your suspension, find the height adjuster at the bottom of each spring and spray them thoroughly with a penetrating lubricant.
To measure Ride Height: What and Where.
Front: There is a small flat-machined area on the bottom of the cast bracket that holds the rear of the Lower Control Arm, between the ribs. This pad should be 180mm +/- 10mm from the floor for new springs - you are allowed another 10mm for used springs. There should be a max difference of 10mm from left to right.
Rear: There is a small flat-machined area on the aft bottom of the large u-shaped bracket that holds the lower transverse control link (the large flat blade). This pad should be 173 +\- 10mm from the floor, with the same 10mm allowance for old springs. There should be a max difference of 10mm from left to right.
You MUST measure, jack and change, then drive the car for at least three or four miles before you re-measure
How to Change the Ride Height.
Turn the front wheels all the way left or right, lube the nut area well with a penetrating spray lubricant, and turn the nut right to raise, left to lower. You can get to the rear (also lubed) with only a little stretching. Adjust the height all the way around and re-measure. When you think that you have it right, drive the car for three or four miles and re-measure, curse and readjust.
Setting the Camber
Set the caster
Turn the caster eccentric (inboard on steel ball joints) until the ball joint is all the way back, the inner end of the ball joint carrier will now be all the way forward.
Set the camber (the top-to-bottom angle of the wheels).
You can check the camber with a 24" level. You want to have 1/32" clearance between the level and the top tire sidewall with the level plumb and touching the lower tire sidewall. The surface that the car is sitting on does impact this - either use a level area, or check the camber, turn the car around and check it again and average the readings.
The camber is adjusted by turning the eccentrics on the lower control arms. The camber eccentric is the outer one for steel ball joints.
After you measure the camber and determine that it needs adjusting, you must jack the car, re-measure the camber and adjust that camber reading enough to change your original reading to 1/32", and then drive the car enough to settle the suspension (several miles!) and recheck the camber.
The rear camber should measure about the same as the front, but is adjusted by an eccentric at the inboard end of the rear link (the transverse vertical blade).
Straightening the Wheels
Straighten the front wheels with the steering wheel. If you want to get everything really straight, pull the small plug on the front of the steering rack on the driver's side and turn the steering shaft until you can see the mark on the steering rack thru the hole. This centers your rack. Pull the steering wheel and straighten it if necessary.
Toe in
Settle the Car (Again)
Before you measure the toe-in, the suspension must be settled by driving the car several miles. You cannot settle the car by bouncing on the fender - it takes about 6-800 pounds to force the car down, and it must be held there for one minute to settle it. Will your aluminum fenders stand that?
Set up
After you get the front ride height and camber set, adjust the toe-in. Easiest way is to "string" the car, ala NASCAR. Use any four convenient objects to securely hold two strings that run beside the car, at about wheel center height and an inch or two from them, and extending a foot or more beyond the ends of the car. Measure the distance between the strings in front of and behind the car, and make these distances identical. Make the distances between each rear wheel center and its string identical. Make the distance between each front wheel center and its string identical. Check to make sure the distance between the strings is identical in front of and behind the car. Warning! The track is rarely the same front and rear, so don't use just the measurements from the wheel centers to set your string!
Setting the Toe-In
Measure the distance from the front of each tire to the string and the distance from the back of the tire to the string. Try to be very consistent on where you measure from on the tires. Do the simple math to get the difference between the front and back measurements on the front tires. Adjust the tie rods (loosen the jam nut, turn the tie rod - don't forget to tighten the jam nut when you finish) on the steering rack to get the tires almost straight ahead, with the smallest amount of toe-in (tires closer together at the front) that you can measure.
Aligning the Car
These procedures will get your alignment close enough to drive the car until you can find an alignment shop that will align your 928 WITHOUT JACKING IT UP. If your alignment shop can't or won't do the alignment without jacking the car up, find another shop.
02-27-2004, 02:28 AM
#3
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Errrr, just make sure there isn't too much toe-in or toe-out before driving to the shop. You'll be fine.
I would probably make sure the ride height was correct, though, since most shops won't do that for you.
...and make sure the shop knows they can't lift the front end, without special knowledge of how to reset it prior to making adjustments.
I would probably make sure the ride height was correct, though, since most shops won't do that for you.
...and make sure the shop knows they can't lift the front end, without special knowledge of how to reset it prior to making adjustments.
02-27-2004, 01:48 PM
#5
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toofast928,
Go to my site for the correct measurements. http://members.rennlist.com/captearlg/
If the car is not settled and you are doing the string toe in, give it about 3/16" on each wheel. As the car settles, it will tend to reduce toe-in . Don't worry about caster/camber, let the shop do it. You won't wear your tires on the way to the shop.
Go to my site for the correct measurements. http://members.rennlist.com/captearlg/
If the car is not settled and you are doing the string toe in, give it about 3/16" on each wheel. As the car settles, it will tend to reduce toe-in . Don't worry about caster/camber, let the shop do it. You won't wear your tires on the way to the shop.
