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Considering doing my own alignment on my 09 Z. I have some good measuring tools and am considering the AMT cam adjusters that appear to set the camber. My car will see street and lots of HPDE so I'm thinking maybe learn to tackle this now. (Suppose Im fairly competent and have good tools and shop etc)
Toe: suppose I can set the toe with custom toe plates and other measuring tools (I have a way of making sure the surface is very level)
Camber: will be set with AMT hardware (assume I dont mess with the upper washers)
Caster: ?
I only have tools to set the toe, so anyone that is doing their own alignments pls recommend measuring tools for camber and caster, thanks!
Last edited by KennyPowers; Dec 26, 2023 at 01:34 PM.
so learning about alignments is great, and I'll throw in my 25 year old guide below for measuring with hand tools. However it's a big job, especially with camber plates.
I'll address your biggest questions...you adjust the caster by moving the lower control arms via the concentrics (or camber plates) or shimming the upper arms. If you move the front of an arm but not the rear...you "swing" the knuckle forward or rearward. My guide below has an estimate for measuring caster with a camber gauge, but you can also measure it directly from the brake caliper bolts.
***I just had a car in the shop that had a prior alignment gone wrong. All of the specs were in range, but the right wheel was rotated forward (hitting the front fender liner) and the left wheel was swung rearward (hitting the rear fender liner. It helps to have a "big picture" view of the car, not just focus on the numbers***
Thanks for the response and the pdf. Looks like the Longacre 52-78290 AccuLevel Pro could be a good way to check camber and measure caster, and its only about $300 so not too bad.
As far as thrust angle, which I assume is the same as "squaring up" the front and rear, is there any way to use the datum points on the frame? I haven't looked too closely yet but I know there are jig systems to repair the frame on all cars. Thinking a custom jig might make quick and accurate work..
your wheels are your data point, as they are what touch the road. I square the rear wheels off of the front hub center UNLESS the car has been damaged, or I have reason to believe the wheel-base is off. You can do the same in reverse to get the steering wheel centered, although a test drive is the only way to get it perfect
Measuring Caster with a camber gauge is the time tested method, but it requires being able to turn EXACTLY the specified amount. That's why I choose to do the 1/2 steering wheel instead of 15degrees. Also I usually just use the brake mount now. On my 4-post lift I can measure if quicker and more accurately directly, instead of via camber change.
Not sure if he's a member here or not but Josh Van Veld is doing a build series on his z06 on youtube and did his own alignment. Lot of good info and his videos are pretty watchable. Planing on attempting this myself too.
Measuring toe with toe plates is QUITE easy to do. The only real negative is that you can get the toe adjustment correct - BUT not have the wheel centered. If that happens - you basically have to move the toe adjustments on either side equal amounts till the steering wheel is centered. The only thing is that you have to make sure to thoroughly "bounce" the car after any adjustment - then roll the car forward, and prevent it from moving backwards (any play in the suspension will manifest itself in toe movements if the car rolls back even a small amount). This bouncing the car - and roling it forward is something very few pro shops do well.
Not too hard to measure camber and if adjustment is needed - that's pretty easy to do as well.
Im hoping a steering wheel holder will assist in any unwanted steering wheel movement while aligning, but agreed on the tech2 (win)..
So.. thinking I might dig in to the idea of doing this. Appears there is some order to the procedure -> we must begin with exhausting the concept/measuring/adjustment of "ride height".
How to set ride height within .001"(I said I liked measuring, ha).. We must properly define "ride height" as the distance between? Im going to guess here and say -> given equal tension/force on both sides of the transverse spring, ride height is the distance between the bottom of the spring (where it meets the a-arm), and the ground(tire surface). Adjusting ride height is done by turning a bolt which moves the spring closer or farther from the ground.
If I ever pass this first step I''ll report back. The big picture (at this point in the investigation) is to machine/fab some fixture that bolts to the frame that allows super fast 4 wheel alignments.. think tinkertoys with linear rail(shaft)
I read about the real high tech guy's worrying about 1/4 degree here and there, and then I read about the diy guys that get within 1/8".
Myself, I prefer to go to a good shop with the right equiptment and let the experts do it.
Then check the tire wear periodically.
Some considerations already arising when just talking about ride height: ride height as defined industry wide as the distance from the bottom of the vehicle(call it frame) to the tire surface(road)..
Suppose you have the adjusting screw all the way in so the spring is as close as possible to the road(lowest adjusted ride height), this will no doubt effect the DWB geometry.. now stick on a large diameter tire. Next consider the opposite, highest adjusted ride height and smaller diameter tire. Both cases the frame to road distance could be the same but the DWB geometry will be different..
I just did mine for the first time after installing monoballs and it wasn’t too bad.
first I leveled the car using a 6’ level and linoleum tiles to get the car flat.
Then I used a longacre camber gauge to get camber where I wanted it. Rolled car forward and backwards about 6-10’ to get suspension to settle after each adjustment.
then loosened tie rod lock nuts and put steering wheel dead center. set up smart strings, measuring from the center of each hub to string to make sure same side-side as well as width of strings at front and back to make sure they were the same so I didn’t create a parallelogram.
I was able to reach under the car with the proper wrench to adjust. Super easy even with a lowered car.
I was rewarded with a centered wheel and a car that tracked straight.
You're doing a four wheel alignment it's not that easy. What $125 for a
Laser alignment is too much?
Its not the cost, its the ability to be able to adjust the settings yourself and not have to rely on a shop to hope they get it right and not just in spec. If I know I have a track day coming up and I can do my own alignment before and after I can get more aggressive with my settings then dial it back when its time to street drive again. Hard is relative, once you understand the basics of it your good to go.
I'd agree its less about the costs and more about knowing what's going on. I"ll be slapping on Pirelli slicks sometime soon so will need to account for the changes in tire diameter between street and track setups.
So back to the books: Chevy calls ride height "trim height" for anyone with a manual. As I stated above Im guessing you want to start by setting ride height first then, camber, caster, and toe last. Chevy does list inspecting the trim height before any alignment, so here's the specs for our cars per the manual, Z and D heights. (not that I need to defend Chevy here but from my understanding of vehicle dynamics, and the comment I made above regarding ride height per industry standard, choosing to measure the angle of the lower control arm, ie the distance between 1 and 2, is a great way to keep consistent geometry, as opposed to measuring the vehicle frame height, see some discussion here using that method)
Home Alignment Or Not?
