Front end alignment
It's a 79 BTW..
Thanks.
If you can, make an appointment with a GM service center. All of their guys are certified, and they may even have a Vette guy there.
Where did you have it done?






I don't like taking an old car to a new car dealership, at least in S. Fla. It' bad enough taking a new one there unless it's under warranty.
Last edited by Jud Chapin; Oct 23, 2007 at 03:56 PM.
The Best of Corvette for Corvette Enthusiasts
1. Front end alignment
2. Rear end alignment
3. Thrust angle alignment
I always tried to encourage thrust angle since this type of alignment ensures that the front tires are in alignment with the rear, thus eliminating dog tracking.
1. Front end alignment
2. Rear end alignment
3. Thrust angle alignment
I always tried to encourage thrust angle since this type of alignment ensures that the front tires are in alignment with the rear, thus eliminating dog tracking.
In the old days of two wheel-only alignment equipment, to do a four-wheel alignment you had to do the front, then back the car onto the rack to do the rear. A thrust angle alignment made sure the tires were aligned to the frame, therefore aligning the front and rear wheels to each other. It's outmoded and unnecessary with modern four wheel equipment.
http://www.tirerack.com/tires/tirete...e.jsp?techid=4
Front-End, Thrust Angle and Four-Wheel Alignment
The different types of alignments offered today are front-end, thrust angle, and four-wheel. During a front-end alignment, only the front axle's angles are measured and adjusted. Front-end alignments are fine for some vehicles featuring a solid rear axle, but confirming that the front tires are positioned directly in front of the rear tires is also important.
On a solid rear axle vehicle, this requires a thrust angle alignment that allows the technician to confirm that all four wheels are "square" with each other. Thrust angle alignments also identify vehicles that would "dog track" going down the road with the rear end offset from the front. If the thrust angle isn't zero on many solid rear axle vehicles, a trip to a frame straightening shop is required to return the rear axle to its original location.
On all vehicles with four-wheel independent suspensions, or front-wheel drive vehicles with adjustable rear suspensions, the appropriate alignment is a four-wheel alignment. This procedure "squares" the vehicle like a thrust angle alignment, and also includes measuring and adjusting the rear axle angles as well as the front.
Not all vehicles are easily adjustable or fully adjustable. Some vehicles require aftermarket kits to allow sufficient adjustment to compensate for accident damage or the change in alignment due to the installation of lowering springs.
When aligning a vehicle, it's appropriate for the vehicle to be carrying its "typical" load. This is important for drivers who continuously carry loads in their vehicles, such as sales representatives with samples or literature in the trunk. Additionally, when a vehicle is used for autocross or track events, some racers will sit in their car, or have the alignment shop "ballast" their vehicle to include the influence of the driver's weight on the suspension angles.
The primary static suspension angles that need to be measured and adjusted are caster, camber, toe and thrust angle. Here's a definition of each angle and its influence on a vehicle and its tires.
This was taken from Road & Track Magazine dated today:
http://www.roadandtravel.com/automot...alignment.aspx
There are two common types of alignment: thrust-angle and four-wheel. Thrust-angle uses the rear wheels of your car to align the front wheels. This is performed only when the alignment equipment says the rear wheels already are aligned. If your rear wheels aren’t already aligned correctly, a four-wheel alignment is performed, first aligning the rear wheels, and then performing the thrust-angle alignment. A thrust-angle alignment can cost between $49 and $79, and a four-wheel alignment from $89 up.
It takes a lot to knock your car out of alignment; your average run-of-the-mill pothole won’t do it.
“You have to actually bend steel to affect alignment,” Goss says. He admits that one of the common misconceptions occurs in the repair shop when customers are given the choice between the “cheaper” thrust-angle alignment and the “premium” four-wheel alignment, when in fact your car might need only the front tires aligned.
Another tip: a repair shop can’t tell what type of alignment you need until they hook it up to their machines, so they can’t charge you for a four-wheel alignment until they have checked it out.
When should you align your wheels? When you steering has an obvious pull, if your car has been in an accident, or if tire wear is uneven.
Just make sure you have it done right. A proper wheel alignment should take about an hour and a half. If you’re only in the waiting room for 10 minutes, it probably wasn’t done right. A proper alignment involves aligning three angles: caster, camber, and toe-in. Some shops do a quick toe-in, which will make your steering feel more exact, but won’t actually align the tires the way they were intended
If a shop with modern, computerized four wheel alignment equipment tells the machine which vehicle is being aligned, it will display the appropriate measurements, including thrust angle. Solid axles and leaf springs are decidedly old tech, and not really applicable to a discussion of C2 or later Corvettes.
Most leaf spring/solid axle vehicles have some wiggle room to realign the axle to the springs, which can then be used to get the front and rear wheels aligned to each other. From my Hunter training years ago, when I think of "thrust angle alignment" I think of getting the front wheels aligned to a rear axle with absolutely zero possible adjustment.
In this day and age, front-only or rear-only alignments are totally obsolete. There's no reason not to mount all four sensors to the wheels in order to get a proper four-wheel reading, even if only the front needs to or can be aligned.
The second article mangles the terminology a bit. A four wheel alignment is a four wheel alignment - not a rear wheel alignment with a thrust angle alignment. The idea of a four wheel alignment is not only to get the front and rear squared to each other, but to get all four squared to the chassis. It's not two separate procedures, it's one big procedure.
Two wheel alignment (front or rear): aligns those wheels to the chassis.
Thrust angle alignment: aligns front wheels to an unadjustable rear axle, eliminating (or at least reducing) dogtracking.
Four wheel alignment: aligns front and rear wheels to each other and the chassis.
Last edited by I'm Batman; Oct 23, 2007 at 08:25 PM.














