I'm about to get into a front end alignment. I bought myself a gauge and I need some help on the order of the adjustments. Correct me if I'mwrong, but I think the order is as follows:

- adjust for camber first
- then adjust for caster, adding shims on the rear bolt for positive caster
- check and adjust for toe

Am I correct here?

 

Caster / Camber / Toe

but either way I always check caster camber at the same time.

caster always changes camber a bit.

What gauge did you buy ?

 

First, welcome to a larger world.


Caster, camber, toe. You want to get fiddling with fore/aft shim relationships out of the way, then add or subtract equal amounts of shim to a given shaft to set camber, then finalize toe making certain to CL the steering wheel in the process.


Tips:


I'll assume you've selected an appropriate baseline from one of the primary resources, such as VBP, Guldstrand, etc., rather than factory settings. If not, I highly recommend doing so, and to strive for minimal tolerances instead of settling for "close enough for government work".


FWIW, I do NOT recommend intentional cross caster or cross camber on any true sportscar application, and definitely do your best to zero/center rear thrust angle.


If you've PS, additional positive caster will help improve feel, but don't go overboard trying to dial in more than practical only to end up bending your shafts with too many shims. If manual, I'd suggest you keep caster to no more than ~2* positive until you decide whether you prefer quicker response vs. more stability (less for the former, more for the latter).


And FYI, a set of 8 hard vinyl tiles (VCT) and some grease make for a decent set of poor-man's floating turntables, if you don't happen to have a set on hand.


Hope that helps.
TSW

 

I bought a Fastrax tool c/w toe adjustment arms.
So your saying adjust shims for caster first and then for camber? I thought it would be opposite. Camber then caster.

 

There really is no set order between caster and camber. Really what you're gonna want to do is to take measurements then analyze what needs to happen shim wise to get you where you want to be. Often times you'll be able to make a shim change that will adjust caster and camber at the same time. For instance, say you find that r/f camber is too negative and caster is too negative as well. In that case taking out a shim out of the front position will make caster and camber more positive at the same time killing two birds at one time. Key is to make as little work for yourself as you can.
FWIW, while I agree that on a track car you dont want cross caster, on a car that will see mostly street I've found(I've literally done 1000's of alignments)that using a bit more caster on the right side(around .5 degrees) will make the car track straight on crowned roads while having nearly no effect on freeways.
Also, old magazines make great turntables also.

 

Actually, it's a little of each, as BOTH of the upper control arms' adjustment points control camber, and the difference in the amount of shims between these two points, controls caster. So you're actually doing a "balancing act" between the two to get both the caster and camber at the desired settings.

 

IMCO adding complication to an otherwise fairly straightforward procedure yields little benefit to the novice tuner seeking advice. Just worry about taking one fundamental step at a time, ordered so as to minimize repetition, and you'll be done and driving in no time.

 

More info I forgot to mention: car has a Borgeson PS system I've been running for over two years.

OK, just so I'm straight. With the car on the ground. If I start to loosen the a-arm nuts, will the shims tend to fall out? Do I jack the frame, slightly, to take the pressure off the shims so they can be altered? I need to get up on the learning curve for this.

 

If you jack the frame, you're essentially changing your alignment, since you're raising the a-arm pivot points, in relation to the ground. What you do, is use a long screwdriver, to pry between the frame and the control arm shaft.

The shims are "slotted", so if someone managed to put them in upside down, yeah, they could slip out, but the chances are slim.

 

Now that you have a 'gauge' (we don't know how accurate and/or repeatable it is), you can spend the next few years figuring out how best to use it.

Not sure why anyone {except maybe someone who did this for a living} would want to do a DIY alignment instead of take it to a shop with really good equipment and really well trained personnel. I mean, we get an alignment on a street car maybe once every 5 years or so.....

 

The only way to take the pressure off the upper control arm is to jack up under the lower control arm as close to the ball joint as possible. That being said, over the years I've found the best way to do these types of front ends(GM style with the upper arm cross shafts mounted inboard of the frame) is to leave the weight of the car on the wheels while doing shim adjustments. When you loosen the nuts the upper arm cross shaft will fall inboard as you loosen the nuts. You can then add/remove shims as needed to get things into spec. Unfortunately, you will have to do a caster swing to remeasure caster every time you make a change to caster while most of the machines I use are able to do live caster readings.

My advise would be to take all the measurements, write them down and make a plan of how you will need to move shims to get where you want to be. Then, make the changes and re measure everything again to see how much change actually occurred. That way will give you some kind of idea of how much change you get in relation to the thickness of the shims you moved.

 

I took my 73, after the suspension rebuild, to the local tire shop down the road. Their oldest tech completed a 4 wheel alignment (using Guldstrand's specs) in under an hour and charged a whopping $80! I even got a nice computer print out. He even had a small collection of shims in his tool box for the odd older car that comes in.

 

Because based on my experience, over the last 40 years, even though the modern equipment has made front end alignment pretty much "fool proof", there are still too many "fools" employed by the shops. The current crop of "front end experts" will tell you "it's in the green, you're good to go", which is a load of BS. They just don't want to spend the extra few minutes to get it on the "nominal" value.


I think the most interesting thing I had someone tell me, was when the former shop lead technician at the local Jaguar dealer said, and I quote, "I can have all the numbers in the green, and STILL have the car going down the road sideways".....


Believe me, if I could afford it, I'd have an alignment rack in my garage!!

 

Yes. Not everyone is so fortunate to have access to a really good alignment shop. And, not everyone settles for only checking it every few years, particularly those of us who may have been afflicted with any sort of high-performance/racing bug (be that drag or AX/RR oriented).

 

And the situation is compounded with a Corvette, as they sit very low, and are unable to be driven on to many alignment racks. The shop that I've been patronizing for years, is unable to get my Corvette on their rack.

Back when I wanted it aligned for the first time, we tried, but it was a "no-go". My friend then sent me to what I referred to as the "artsy-fartsy" sports car emporium in the city. They had a modern "rack", but they had it installed in conjunction with a "pit", so the ramps were level with the floor, and a low car had no issues. Granted, they weren't shy about charging the $$$ for an alignment, but they had the equipment, and did good work. Unfortunately, the owner decided to retire, and the shop closed....

 

Good on you! I`ve always done my own alignments whether it was working at a shop or at home with my own equipment. I know the "Its in the green mentality". Green means more money for them!

 

That's why you spend some time and effort searching out which alignment shop in your area (if any!) is qualified and capable of doing a good job on your cars (including Corvettes). But, I think, that would take less effort than searching for and buying GOOD QUALITY equipment to make DIY alignments.

But, everyone is different....and some folks just feel the need to re-engineer the wheel...just because. More power to ya'! Good luck.

 

So doing your own work on your own car is re-engineering the wheel? Wheel alignments are not rocket science. I have a couple of good quality alignment tools and I do my own. I can drive down the highway with one finger on the wheel and my elbow hanging out the window. Drives perfect and I have the luxury of checking the alignment any time I want to. I don't want anyone else working on my car. Some people just like doing their own work, it's not about trying to "re-engineer the wheel".

 

 

Smarter equipment has made dumber techs. And there is no such thing as a right or wrong alignment. If you have your own $150 bubble and a couple (4) pieceds of mild steel with grease, you can learn to do your own alignment. I bought one when I was building my Cobra now will never even consider taking a car in for an alignment. It'll either be under warranty or not to be touched by anyone but me.