diy camber/caster adjustment
07-18-2005, 10:18 PM
#1
diy camber/caster adjustment How do you adjust camber and caster? All I could find from a search was that there's a special tool you can get, but nothing about how the adjustment is made. Are there shims involved? And is it possible without that tool?
07-19-2005, 03:32 PM
#3
Yes, that's where the adjustment is. The front LCA mounting bolt is loosened to adjust the camber, and the rear bolt is to adjust the caster. Moving the LCA outward in the front increases negative camber; moving the rear of the LCA outward increases postive caster. The two will have an effect on each other, as well as the toe. Don't drive the car until you reset the toe!
07-19-2005, 03:58 PM
#4
Originally Posted by Cal
Yes, that's where the adjustment is. The front LCA mounting bolt is loosened to adjust the camber, and the rear bolt is to adjust the caster. Moving the LCA outward in the front increases negative camber; moving the rear of the LCA outward increases postive caster. The two will have an effect on each other, as well as the toe. Don't drive the car until you reset the toe!
Also just found this that looks to be from a service manual:
alignment specs & procedures
07-19-2005, 06:10 PM
#5
Look, let me make this whole process a lot easier for you.
You don't need any special tools, just a tape measure, small pinch bar, and a good helper (you might want to leave the female out of this, LOL.) Just raise the car and loosen all those bolts and slam the LCA's out to the end of the slots with the pinch bar. Then tighten the bolts and spin tires against a sharp piece of chalk or grease pencil. Now lower the car and bounce the nose of the car a few times (actually the female may be useful for this part, LOL.) Now use the tape and the helper to measure between the lines on the tires, once on the leading edge, and once on the trailing edge. Subtract the two measurements, and if it is not zero (within a 32nd of an inch) adjust both tie rods an equal amount until it is. When you adjust the tie rods, turn them one-sixth of a turn at a time, using the wrench flats as a reference.
You are done, and you now have a performance wheel alighment that would cost $100 down town.
You don't need any special tools, just a tape measure, small pinch bar, and a good helper (you might want to leave the female out of this, LOL.) Just raise the car and loosen all those bolts and slam the LCA's out to the end of the slots with the pinch bar. Then tighten the bolts and spin tires against a sharp piece of chalk or grease pencil. Now lower the car and bounce the nose of the car a few times (actually the female may be useful for this part, LOL.) Now use the tape and the helper to measure between the lines on the tires, once on the leading edge, and once on the trailing edge. Subtract the two measurements, and if it is not zero (within a 32nd of an inch) adjust both tie rods an equal amount until it is. When you adjust the tie rods, turn them one-sixth of a turn at a time, using the wrench flats as a reference.
You are done, and you now have a performance wheel alighment that would cost $100 down town.
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07-20-2005, 10:38 PM
#9
The camber and caster have little to do with whether the car pulls to one side or not. That's more often caused by tire issues or worn front end parts. But if you have unequal toe in side to side, that will make it pull. The best way to adjust that is to just adjust and test drive until it goes straight, changing it only one flat at a time. The toe will actually have to be off a little to compensate for the crown of the road, but for a race setup you may not want that.
Now the best way to do an alignment is to determine where the thrust line is from the rear axle, and do a four-wheel alignment. But I doubt many shops even do that unless you request it and pay them extra.
In most cases, you can just assume the front end is already on the thrust line and adjust the toe equally on both sides. The toe is always the last thing you adjust when doing an alignment. Acutally, if any ride height adjustments are to made, that should be done first. Then usually you adjust the camber, then check caster. If you don't like the caster, you can change that, but then you would need to go back and correct camber again since they effect each other. Once you have the ride height, caster and camber done, you can adjust the toe to what you prefer. Then you test drive the car, and if it pulls a little to one side, you can adjust the toe a small amount, opposite directions for each side.
As you can see, doing a real good wheel alignment can take some time, depending on how fussy you want to be. You can bet most shops aren't going to go to that much time and trouble, because they wouldn't make any money. So if you are picky, it's best to learn how to do it yourself.
Now for a performance alignment on an fbody, you can never get enough negative camber out of a stock car, so first thing you want to max that out. That will probably limit how much caster you can get, but it's less important, so you can just accept what ever is left over for that. The set the toe to zero, and you're done. Some people like a little toe out (maybe a 1/16 or 1/8 inch) to get street tires to turn in quicker, but I think you lose more by upsetting the Achkerman. That's how the two front wheels track each other in a turn. I think it's better to just use stiffer tire sidewalls or put a give tire on a wider wheel to improve turn in.
Now the best way to do an alignment is to determine where the thrust line is from the rear axle, and do a four-wheel alignment. But I doubt many shops even do that unless you request it and pay them extra.
In most cases, you can just assume the front end is already on the thrust line and adjust the toe equally on both sides. The toe is always the last thing you adjust when doing an alignment. Acutally, if any ride height adjustments are to made, that should be done first. Then usually you adjust the camber, then check caster. If you don't like the caster, you can change that, but then you would need to go back and correct camber again since they effect each other. Once you have the ride height, caster and camber done, you can adjust the toe to what you prefer. Then you test drive the car, and if it pulls a little to one side, you can adjust the toe a small amount, opposite directions for each side.
As you can see, doing a real good wheel alignment can take some time, depending on how fussy you want to be. You can bet most shops aren't going to go to that much time and trouble, because they wouldn't make any money. So if you are picky, it's best to learn how to do it yourself.
Now for a performance alignment on an fbody, you can never get enough negative camber out of a stock car, so first thing you want to max that out. That will probably limit how much caster you can get, but it's less important, so you can just accept what ever is left over for that. The set the toe to zero, and you're done. Some people like a little toe out (maybe a 1/16 or 1/8 inch) to get street tires to turn in quicker, but I think you lose more by upsetting the Achkerman. That's how the two front wheels track each other in a turn. I think it's better to just use stiffer tire sidewalls or put a give tire on a wider wheel to improve turn in.
07-21-2005, 02:28 AM
#11
Normally you make alignment changes with weight on the wheels and the suspension fully loaded. If you are ultra-picky, you can have someone your weight sit in the driver's seat or use some suitable balast.
The front wheels should be on a device called "slip plates" so they can move in any direction even with the car's weight on them. Slip plates are available for anywhere from $120 to $450, depending on whether you go to Harbor Frieght or an Oval Track racer supply. But you can easily make your own, or, if your going to have the car on the floor, a small stack of yard-sized garbage bags will do it. If you're going to do it on ramps, you need some stiff slip plates you can place on top of the ramps. I made my own out of one-foot square, quarter inch thick steel from Lowe's Hardware for the base, and a piece of 16 gauge sheet metal the same size on top of that, with some chassis grease inbetween. They have some other features just to make them nicer, but what I just described will work. The car should be as level as possible for any alighment measurements, so if you use ramps, the rear tires should be on some also. Besides the chalk line on the tire tread, another way to do it is with some kind of flat plates that some helpers hold against the wheel. If you're like me and don't have any willing tool bitches around, you can just bungee the plates to the wheels. I actually have a pair of steel frames that I welded up just for doing this. It helps to have them for a lowered car. They also touch the wheels rather than the tires. I can post pics of all this stuff if you're interested. Of course if you're just going to measure it and not change it, you don't need the slip plates, just the toe plates.
The front wheels should be on a device called "slip plates" so they can move in any direction even with the car's weight on them. Slip plates are available for anywhere from $120 to $450, depending on whether you go to Harbor Frieght or an Oval Track racer supply. But you can easily make your own, or, if your going to have the car on the floor, a small stack of yard-sized garbage bags will do it. If you're going to do it on ramps, you need some stiff slip plates you can place on top of the ramps. I made my own out of one-foot square, quarter inch thick steel from Lowe's Hardware for the base, and a piece of 16 gauge sheet metal the same size on top of that, with some chassis grease inbetween. They have some other features just to make them nicer, but what I just described will work. The car should be as level as possible for any alighment measurements, so if you use ramps, the rear tires should be on some also. Besides the chalk line on the tire tread, another way to do it is with some kind of flat plates that some helpers hold against the wheel. If you're like me and don't have any willing tool bitches around, you can just bungee the plates to the wheels. I actually have a pair of steel frames that I welded up just for doing this. It helps to have them for a lowered car. They also touch the wheels rather than the tires. I can post pics of all this stuff if you're interested. Of course if you're just going to measure it and not change it, you don't need the slip plates, just the toe plates.
07-21-2005, 11:30 AM
#14
Originally Posted by Cal
The camber and caster have little to do with whether the car pulls to one side or not. That's more often caused by tire issues or worn front end parts. But if you have unequal toe in side to side, that will make it pull. The best way to adjust that is to just adjust and test drive until it goes straight, changing it only one flat at a time. The toe will actually have to be off a little to compensate for the crown of the road, but for a race setup you may not want that.
07-21-2005, 12:44 PM
#15
Are you sure a tire problem isn't what's causing it to pull? Have the same presure in tires on the right and left sides? Tried rotating the tires? If it is a toe problem, yes you want more toe in on the right side, but also an equal amount of toe out on the left side to maintain zero toe total, between both front tires, unless that's what is off. Did that make sense? In other words, you want the front tires parallel, which is where the tape measure comes in. That total toe in of 1/8" is way too much IMO, I would set that to zero. Steering will be more responsive and tire wear better.
I don't see how caster could make it pull; caster only makes the wheels want to return to the center; it doesn't determine where center is. It works exactly like the rake on a motorcycle fork. In fact, I don't think the caster is exactly equal on my car, and it rolls straight hands off.
I don't see how caster could make it pull; caster only makes the wheels want to return to the center; it doesn't determine where center is. It works exactly like the rake on a motorcycle fork. In fact, I don't think the caster is exactly equal on my car, and it rolls straight hands off.
