The cam bolts have offset heads. As you turn it, it pulls in or out on the spindle to tip the wheel in or out on top. The advantage to using them are it makes making very precise adjustments faster and easier, and it helps to hold the spindle adjustment from slipping when you hit potholes. The lower strut mounting hole can also be made oblong with a die grinder to allow for the same adjustment without using the cam bolts, but then you have to rely on the clamping strength of the bolts to hold the spindle in place. Normally that is not a problem and that is the way many cars are meant to be adjusted after they leave the assembly line. It takes more trial and error to get each side set right so it takes more time to grind the holes in preparation for doing the alignment and to actually do the alignment. It takes less time to take things apart to put the cam bolts in but they can be reused when the struts need to be replaced. If they just grind the holes in the struts, that will have to be done again to the new ones when they're replaced in the future.
You have to look at the "camber" values first before deciding if those cam bolts are needed. Camber is the inward or outward tilt of the wheel as viewed from in front of the car. Most cars call for the wheels to be tipped out a very little bit on top but not enough to see by eye. If your tires are rubbing, the first thing is to see what they're rubbing on. If the wheels are tipped in too much, particularly if it's just on one side, suspension ride height is more likely sagged and that has changed the geometry and the motions the wheels go through as they go up and down. Alignment specialists get pretty picky about correcting ride height problems because if the suspension is sagged, there is going to be greatly accelerated tire wear even when the numbers on the alignment computer are perfect.
If the tires are rubbing on the struts, that's from too much negative camber and the wheels need to be stood up straighter or tipped out a little on top. If they're rubbing on the inner fender, that is an issue with tire size. Adjusting camber might alleviate the rubbing but that is not a proper fix because you can't take into account every motion the wheel and tire might go through due to turning left and right, bouncing over bumpy roads, and body lean from cornering. Those things were all factored in when they designed the car around a specified size tire. You also have to look at the current tire wear. If camber is out-of-adjustment badly enough, you'll see increased wear on one edge of that tire's tread. Also, tires want to steer in the direction they're leaning. If camber is wrong on just one wheel, the car will pull in the direction it is leaning. That is one clue an alignment is needed. The other clues are that tire wear, and when the steering wheel is not centered.
Friday, March 15th, 2013 AT 8:50 PM