It sounds like you're confusing "toe" with "camber". Individual toe is the direction a wheel is steering when the steering wheel is straight. "Total toe" is just the total of the two toe readings together. Camber has to do with the wheel being tipped in or out on top. Both of these angles are major contributors to tire wear.
If the alignment specialist is conscientious enough to not take your money when he knows the alignment can't be expected to hold, he should be willing to tell you what is still wrong. Forcing you to guess at what's happening isn't going to help anyone.
Since you can actually see the wheels change orientation, you should be able to cause that same change with a pry bar and the truck jacked up. Be aware checking various parts for slop or movement due to wear requires the truck to be supported in multiple ways. Any load has to be removed from the part being inspected so that movement can be observed. For example, the jack stands should be under the axle housing to hold it steady, then pry up and down under the tire and watch for movement in the lower, load-carrying ball joint. When you have upper and lower control arms, supporting the truck this way lets the suspension hang by the upper control arm and ball joint. That stress will prevent movement between the ball and socket in the upper joint, so to check them, the truck must be lowered off the jack stands and onto the tires. Upper ball joints of this type are best checked with the tires resting on turntables on a drive-on alignment rack. That way they'll be sitting at normal ride height where the most wear takes place and will be easiest to find. Pry the control arm up and down, then try to pry the spindle in various directions, while watching for looseness.
The bushings you listed were good suspects, but most people don't understand the importance of the coil springs. The springs have little importance with Ford's older solid "I-beam" front axle, but with all other front axle designs, correct ride height is critical for best tire wear. With sagged springs, the geometric relationship between all the suspension system parts changes the arcs the control arms go through as the vehicle bounces up and down over bumpy roads. The amount of movement in and out on top of the wheel will increase a lot when the suspension ride height has sagged. Tire wear, especially on both edges of the thread, will be very poor even when the numbers on the alignment computer look perfect. Those numbers only pertain to a vehicle that is standing still. By replacing the springs, you've eliminated one of the things that will cause us to refuse to align a vehicle. Every shop has a small book that shows every model and year, where to take those measurements, and what they should be.
To see a really good example of how the springs affect the alignment, look at a 4wd Ranger or a Bronco 2 when it's raised on a hoist or jacked up in front. With their twin I-beam front suspension system, ride quality is improved slightly over the solid I-beam design, but good tire wear is almost impossible to achieve. You'll see how horribly the wheels are tipped out on top. Sagged springs will cause the opposite; the wheels will be tipped in on top, and the tires will run on the inner edges and wear out very quickly.
Look at your steering linkages too. On vehicles that use an idler arm, grab the steering linkage where it connects to the idler arm and force it up and down. A typical spec is 1/16" movement is allowed. With significantly more than that, you'll also see the right front wheel turn left and right as you move the arm up and down. That is changing the right toe reading, which makes for excessive steering wander, and it affects total toe, which is a big contributor to tire wear on both front tires.
When the vehicle is jacked up, or better yet, resting on turntables, try to turn each front wheel left and right by hand. If you can move one without causing the other wheel to turn, there is something loose in the steering linkage. You can find that by watching the linkage while a helper tugs on the wheel.
There are other things that can affect setting a straight steering wheel during the alignment that don't affect tire wear or pulling to one side. Specifically, that would be universal joints or other flexible couplings in the steering shaft. If a coupler is worn enough to allow play in the steering wheel, it is usually bad enough to feel a clunk or rattle too. A vehicle with a worn coupler can be aligned as long as the customer is informed as to why the steering wheel can't be guaranteed to be straight. A lot of truck steering linkages are designed with one total toe adjustment to set that for best tire wear, then a totally different adjustment that only centers the steering wheel. This includes '94 and newer Dodge trucks, a lot of Ford models, and a few older GM trucks. With that design, once the worn coupler is replaced, if the steering wheel is off-center, a competent do-it-yourselfer can make the adjustment to center the wheel. The alignment won't be affected by changing that adjustment.
When two separate, but identical toe adjustments are used, as typical of almost all front-wheel-drive cars and most older rear-wheel-drive models, it is best to have an off-center steering wheel readjusted at the alignment shop after parts are replaced in the steering shaft. It takes just a little experience to know how to tweak each tie rod end when you have rack and pinion steering. Tighten one side to turn that wheel out and loosen the other one to turn that wheel in. By being careful to turn each one exactly the same amount keeps total toe correct, but you'll have to turn the steering wheel, hopefully the exact amount, for it to be centered when the wheels are straight ahead.
Tweaking the tie rods on older rear-wheel-drive vehicles can cause some problems, so it's best done on the alignment rack. This applies mainly to Chrysler and GM vehicles that use inner and outer tie rod ends joined with a threaded tube, which is the adjustment. One tie rod has normal threads, and the other has backward threads. On GM vehicles, the outer tie rod always had the normal threads, so you could figure out which way to turn it to lengthen or shorten the linkage. The problem was these had a very high failure rate, meaning it was likely the parts were not original. Rather than wasting a lot of our customers' money on the time it took to unscrew those rusty parts, it was less expensive to install two new tie ride ends with a new tube. With those three parts screwed together, that entire assembly could be installed either way. Now you can't be sure if the normal threads were on the inner or the outer tie rod end. Even worse, on older Chrysler products, that assembly could have been bolted on either way at the factory. Both tie rod ends looked the same, so if the threads were covered in dirt, you couldn't be sure of turning the adjuster the right way unless the vehicle was on the alignment rack.
When Ford used this design, one tie rod end was typically a lot longer than the other one, so they couldn't be mixed up, but unless you remember which one has the normal thread, you can't be sure you're going to turn the adjuster the right way. Too many times I've been fooled when I examined the threads, then, due to dirt and other factors, what I thought was the backward thread turned out to be the normal thread. Once one of them is turned the wrong way, and you go out on a test-drive and find the steering wheel didn't change, or it's off-center even more, the confusion just about guarantees total toe is going to be wrong. You're better off just heading back onto the alignment rack when the steering wheel needs to be centered.
Ask your mechanic what he found that made him refuse to align your truck. It sounds like you've more than covered the most common things. Once we have that information, we'll figure out where to go next.
Monday, October 21st, 2019 AT 5:26 PM
