Aligning SONEAT

Equipment used:

• Toe gauge (To Be Discussed)
• Camber gauge (TBD)
• Caster gauge (TBD)
• Bungee cord
• Chalk
• Open-end wrenches of various sizes
• 13mm socket and ratchet
• Big “prying” screwdriver and small screwdriver (that I didn’t care if bent because it is Craftsman anyway)
• Jack and jackstand
• Vernier caliper
• Tie-down straps
• Flat garage floor / driveway.

All of this stuff is basic home workshop stuff except the Toe gauge, Camber gauge, and Caster gauge.   How about those things?

Toe Gauge

The “toe” measurement is the difference in distance between the front and the rear of a pair of tires on the same axle. 

I built a very simple tool out of bits grabbed from my scrap material bin…

1.       I grabbed the extruded aluminum track salvaged when I replaced the hanging blinds for the sliding glass door in my town home.

2.       I yanked this square looking wire frame salvaged from an old filing cabinet.  (It’s that wire thingie that holds file folders in place.)  I cut two lengths to about 8” long and included the corner of the “frame” so that I had about an inch of bent tip left.  Then I filed those tips to a point.

3.       A piece of 2x2 poplar about 8” long got cut in half.  Then I whittled it down until it would stuff into the aluminum hanging blinds track and just barely slide when urged.  These were both drilled with a hole to fit the pointy wire thingies.  The pointy wire thingies were stuck in the holes and secured with a little bit of glue.

4.       I took a length of 2x4 and cut it in half to get two pieces about 6” long.  Then I traced an outline of the end of the aluminum track onto each.  I used my drill to drill a bunch of holes inside that outline.  A hammer and wood chisel removed the extra material until the aluminum track fit snugly within the chiseled holes.

5.       Put it all together to make a nifty Toe-Gauge!

Camber Gauge

“Camber” is the degree of inward/outward tilt of the top of the tire from true vertical.

Again, I made a tool out of spare parts and scrap materials.

1. I found a length of aluminum angle and cut it to XXXXXXX”, so it would just fit within the lip-edges of the wheel.
2. I drilled a hole into one end of the aluminum angle and then filed it into a hexagonal shape with a triangle jewelers file.  The hole was made to be a tight fit for a ½” nut.
3. I pressed the ½” nut into the hole with my bench-vise and applied some epoxy to keep the nut from loosening and falling out.
4. I stuck a piece of padded tape to the other end of the aluminum angle to match the raised height of the nut I pressed in, thus keeping things all level and in line and happy.
5. Years ago I found a small (8”) bubble level in the trunk of an old Saab in a junkyard.  I secured this level to the aluminum angle with a couple screws.
6. Thread a bolt into the nut and add a bungee cord to the mix and you have a camber gauge!

No, this gauge cannot tell you what the degrees of camber are but you can figure it out with some trigonometry if you are so inclined.  I wasn’t.  All I cared to know was that the camber was equal from side to side and whether it was positive or negative.

Caster gauge

“Caster” is the measurement between the tire’s vertical centerline and the centerline of the steering axis through the upper and lower balljoints.

I didn’t make this tool, I used a 2’ bubble level and a bungee cord.  Again, it can’t tell you the degree of caster all by itself but it is good enough to see if the left and right sides are the same or not and whether the measurement is positive or negative.

Alignment

So, the first step was to prepare the Sonett to be aligned.  “Brace yourselves!  There’s an alignment coming!”

1. Place the car on level ground.  You don’t want one wheel sitting in a pothole or resting on a bump… that will throw everything off.
2. Make sure the steering is situated to the middle and secure it so that it cannot move.  (I like to use genuine Swedish tie-straps and keep things in the family.)
3. Jack up the front end and put some jackstands under it.  Get a piece of chalk and press it against the tire and then spin the tire.  This will give you a chalk line all the way around the circumference of the tire.  Repeat with the other tire.  Get the toe-gauge and set it up so that one of the pointers is pressing lightly against the tire in the middle of the chalk line.  Spin the tire again, scratching a fine line in the chalk all the way around.  Repeat with the other tire.
4. Optionally, you can place something resembling the driver’s weight in the drivers seat, to simulate an “on the road” weight distribution.  I didn’t bother.  I forgot about it at the time and the only thing I had was some bags of planting soil anyway.  I don’t think I want to risk filling my seat with dirt.
5. Let the car down off the jacks, make sure the e-brake is off and the car is out of gear, and jump up and down on the bumpers to “settle” the car on its suspension.

The second step was to get some baseline measurements so that I knew where I was starting from.   The photos to the right show from whence I began.

1. I backed the adjustment screw on my camber-gauge all the way out and affixed it to the right front wheel with a bungee cord.  The bubble level showed POSITIVE camber.  Both sides were set with some positive camber.  Driver's side - Passenger's side
2. I got my 2’ level and held it to the ends of the bolts that affix the balljoints to the A-arms.  This allowed me to see that I had some degrees of positive caster on each wheel and that they were equal.   Driver's side - Passenger's side
3. Placing the toe-gauge in front of the tires I adjusted the pointers so that they matched up with the scribed lines in the chalk.  Then I moved the gauge to the rear of the tires without moving the pointers and matched on side with the scribe line.  Going over to the other (drivers) side I could see that the pointer was pointing about ¼” to the inside of the scribe line.  That means SOENAT has about ¼” toe-in.

What I WANT for my “race” alignment is… as much negative camber as I can manage, about the same positive caster as I have currently, and about ¼” toe-out so…

1. I loosen all the bolts holding the upper A-arms in place and throw in 2 “thick” shims under each end (4 per side).  Then I tighten things down and re-check the camber.  I’ve got it to almost straight up and down.
2. Loosen all the bolts again.  Gather up all the shims I have and throw them ALL in there.  I had enough spacers to double my previous count.  So in total I added 4 “thick” shims under each end (8 per side).  Check the camber and see that I have some significant negative camber now.  Good thing too, ‘cause I’m all out of shims.  Driver's side bubble | screw - Passenger's side bubble | screw
3. I want to check the caster and make sure it hasn’t moved much.  It shouldn’t have, since I put the same thickness spacers under the front and rear ends of the A-arms, but it is good to check anyway.  Yep, just where they were when I began, with a little bit of bubble of positive caster.  Fine.
4. A byproduct of the camber adjustment is that my toe adjustment goes completely whacko!  Since the Sonett is a “rear steer” car (meaning that the steering rack sits behind the front axle line) as I gain negative camber I add toe-in.  I’ve now got copious amounts of toe-in, over 1 ½” of toe-in.  Driver's side - Passenger's side.   Time to adjust toe.
5. I loosen the rod-end locknut on each of the steering tie-rods and back them in, all the way to the end of the available threads.
6. Then just for good measure I check where they are currently adjusted to, with my vernier caliper.
7. Then I start turning the tie-rod so that it pulls the wheel back towards toe-out.  This is turning the tie-rod INTO the rod-end.  As I am doing this I am watching the wheel change its toe angle and I begin to wonder if I am going to run out of adjustment before it gets to where I want it?  Well, almost… I bottom out the tie-rod in the rod-end on both sides of the car!  So I check that both sides are the same (even though I know both sides are bottomed out) and then check the toe.  I’ve got about ¼” of toe-out!  Phew.  What this means is that back when I was indiscriminately tossing alignment shims under the A-arms I could not have put any more negative camber into the adjustment and still gotten the toe adjusted to where I wanted it, even if I had more shims to put in.  That is unless I modified the tie rods (ground the ends down) so that they could be turned deeper into the rod-ends.
8. Make sure all the bolts and locknuts are tight.
9. Bounce on the bumpers of the car to settle the car and check everything again to be sure.  Yep, all’s well in alignment-land.

A test drive revealed easier and more eager turn-in.  I wasn’t willing to really push the new settings to see if the ultimate grip had been improved.  The grip levels of this car on race tires are so high that it begins to surpass ridiculous on public roads.   A more definitive test would have to wait until Sunday when I had an autocross scheduled.


Well, here's an update on how well the alignment changes turned out!

-STEFAN


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