It can't be aligned to fix the problems altering ride height causes.
If raising or lowering a vehicle could be done in a safe manner, don't you think the manufacturers would offer them that way? Look at the stupid young kids lowering their cars, and the guys raising their trucks. There is obviously a market for those things. The manufacturers, and pretty soon, YOU, are smarter than that, and they know they will end up in court.
First lets start with what you caused by changing the ride height. If you look at that track bar, you'll see it doesn't sit parallel to the ground or to the axle. It's lower on the passenger side. When you raise the suspension, the bar pivots and the passenger end on the axle housing pivots toward the driver's side. That bar is what sets the axle's position so it is going to move the axle to the left. That design is already a poor one with steering wander a very common problem. It is aggravated by the four control arms that are almost perfectly in parallel so they offer no resistance against the axle shifting sideways. Jeeps use the same design but if you look down on them from on top, both pairs of arms form a cross. That design depends less on the track bar than the trucks do.
As a side note, I removed a track bar from a new truck to install on a customer's truck when they were out-of-stock. Later, when I had to put the new one on that new truck, I had a real hard time driving it in through a 12-foot-wide garage door. As the axle shifts left and right, it is moving in relation to the steering linkage, so the wheels turn, ... A lot. There's no way you can drive it at walking speed and not run into something. That's also why just a tiny amount of play in the joints results in miserable steering wander.
The control arms sit lower on the front than where they attach by the firewall. Lowering the axle pivots it rearward a little. It's not that tiny difference that's the issue. It's the amount of arc they go through as the truck goes up and down on the road. The relationship between the steering arms on the spindles and the pitman arm on the steering gearbox changes more than normal as the truck bounces. You can see that by the wheels and tires turning to one side when you bounce the truck up and down.
You also changed the pitch of the steering linkage. The linkage must be perfectly parallel to the ground, (actually, parallel to the axle housing, which is parallel to the ground). When it is not, the wheels will turn one way when the suspension goes up and the other way when it goes down over bumps.
I can understand the pulling but I can't explain why it started now because you should have a solid front axle. There's five things that can cause a pull. One is a tire pull. You didn't change that. The next are the three primary alignment angles, caster, camber, and toe, and simply raising the suspension on this design won't change those. The important one is "scrub radius" and it should not change either in this case. This is a real problem on cars with independent suspension. If you look at the upper and lower steering pivots from in front of the vehicle, the two ball joints on your truck, and draw an imaginary line through them, that line must intersect the road surface right in the middle of the tire tread. Raising the body on the suspension won't change that, but people do it so they can put on oversize wheels and tires, and that WILL drastically alter scrub radius. Each tire drags going down the road from friction. Scrub radius makes the outer half of the tire tread pull back and try to make the entire steering system turn to the outside. The inner half of the tread tries to make the entire steering system turn toward the center of the truck. The two forces counteract each other equally making the vehicle respond very little to bumps in the road. Think of riding a bicycle with a passenger on the back. If they sit in the middle, you can ride normally, but if they sit off to one side, you not only have to lean the other way to avoid being pulled in a circle, you have to lean even further when you hit a bump. You've just messed up that balance on your truck. Even if you can get rid of the pull, you aren't going to be happy on long trips. Controlling the steering wander is going to be very tiring.
Camber is the main alignment angle affecting pull and tire wear. That's looking at the wheel from in front, how much it leans in or out on top. With a solid axle design, that is only adjustable by installing a special offset upper ball joint once you know how much correction is needed. If the truck was never crashed, that might be necessary once in the life of 10 percent of the trucks out there. That axle is a tough design and rarely needs adjustment.
Caster also affects pulling but has very little affect on tire wear. That is looking at the line through the two ball joints as viewed from the side. That line is always tipped to the rear on top, like the fork of a bicycle. There's a wide range of adjustment that is acceptable, but what is important to prevent a pull is that both sides are the same. Caster is adjustable on your truck by offset "cam bolts" at the front of the lower control arms, but being a solid axle, all you can do is adjust the entire axle to adjust caster equally on both sides. You can't adjust just one side to eliminate a pull. So we know that didn't change.
Toe is the direction the tires are steering. That didn't change just from raising the suspension, and it is not adjusted to correct a pull. Doing so would cause severe tire wear. If it was accidentally misadjusted during the alignment, that COULD introduce a pull that wasn't there before.
My biggest concern, and the reason I hope you take this disaster off, is the potential for a lawsuit. You can easily end up sitting in a courtroom after the OTHER guy ran the red light and caused a crash. An insurance investigator or a lawyer is going to pick your truck apart looking for these kinds of modifications, and they WILL convince a jury that you were partly at fault for that crash because you were less able to avoid it, ... And they will be right. The most obvious result of the modification is raising the center of gravity. That adversely affects handling, cornering, and steering control. Why do you think the NASCAR guys want their cars dragging on the ground? You created the opposite of that good handling.
The less-known result is reduced braking ability. You may feel like the brakes are really great because you're being thrown forward in the cab more, but two things are working against you, and the lawyers know it. More weight is being transferred onto the front tires under hard braking. That means less weight on the rear. Your truck has a proportioning valve in the brake hydraulic system that was carefully matched to the weight distribution based on engine size, options on the truck, brake size, and expected weight transfer. The careful calculations that went into selecting the proper valve are out the window when you change any of those variables. Now you'll have very easy rear-wheel lockup under moderate braking. Skidding tires have no traction. Even if you have rear-wheel-anti-lock brakes, which most trucks do, that system is going to kick in more often. Unlike four-wheel anti-lock brakes, RWAL systems only reduce brake fluid pressure. They don't reapply the brake once the locking is stopped. That means you have less braking power when they activate. Their purpose is not to make you stop faster, which is what you need when that guy runs the red light. Their purpose is for you to maintain steering control without the rear end passing the front. You seriously reduced that ability, and that is how you can end up being found partially at fault for the other guy's mistake.
To add insult to injury, most experienced alignment mechanics, me included, will not align or repair any vehicle with altered ride height. As a suspension and alignment specialist for 16 years, ten at a very nice family-owned Chrysler dealership, I had my manager's blessing to refuse to work on any vehicle when the owner refused allowing me to correct ride height. We have books that show every vehicle, where to take the measurements, and what they should be. My bosses understood the legal ramifications of working on altered cars and trucks, and they appreciated the fact that I did too.
If you insist on going ahead with wrecking the handling characteristics built into your truck, there are a couple of things I can suggest to get rid of the pull, but I can't help with the handling. First, just to be sure we're talking about the same thing, a pull is when the truck drifts to one side of the road when you let go of the steering wheel. Too many people confuse that with a steering wheel that is simply off-center. Of course the vehicle will steer to one side when they hold the steering wheel straight. That is not a pull. That is an off-center steering wheel that by itself will not usually cause a pull, and by itself, won't cause tire wear. Your steering wheel will be off-center after raising the ride height, due to shifting the axle's position in relation to the steering linkages, but that is a simple adjustment you can do without needing an alignment.
Monday, March 25th, 2019 AT 12:06 PM
(Merged)
