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allignment

2K views 6 replies 3 participants last post by  LATECH 
#1 ·
What are the general rules for setting toe in and toe out alignment. How do you set camber on an A frame front end? How do you set caster on the same front end?
 
#2 ·
We will assume you have a early GM B Body here for the sake of clarification. The have an upper and lower control arm ( or A Arm) if you will.

Caster is first. The caster is adjusted by moving the upper A Arm forward or back ,accomplished by adding or removing shims at the front or rear mounting stud of the upper A Arm shaft.The lower A arm, or control arm is fixed and not adjustable. No adjustment is made on the lower.
Each time you add or remove shims, you need to perform a caster sweep to measure it. Measuring it is dependant on the type of machine you are using.
Once you get the caster within specs, then you need to get camber pulled in or out, to around zero, or a tad on the + side.
This entails going back to adding or removing shims at the same place you did to adjust the caster. You add or remove shims ,however to keep the caster adjustment that you just adjusted, you need to add or subtract the same thickness of shim front and back. That way the location of the upper ball joint stays the same front to rear, caster does not change, but by adding and subtracting equal amounts, the camber changes as the balljoint is moves in or out, perpendicualer to the suspension and lower ball joint, which leans the wheel and tire in or out at the top.
Last but not least would be toe in.
That is usually set near zero or at just a small amount toed in as suspension loads against the bushings as the car rockets down the freeway, which can negate a small amount of toe in as the bushings will collapse a small amount(even brand new ones), so a small amount of toe in is recommended.
Toe is adjusted by turning the tie rod adjusting collars , either lengthening or shortening them. Also, at the same time keeping the steering wheel straight ahead, so the wheel is level when the car is going straight down the road.
many of the new alignment racks have a steer ahead and total toe reading, left and right, which makes it real sweet and simple to get the toe correct and the steering wheel level.
 
#3 ·
What is an "A frame"? Do you mean a Ford Model A 1928-31? Or do you mean a General Motors "A" body (Chevelle, Skylark, ect)?

If it's the Model A you change camber by bending the axle, and of course it's largely left as is. Caster by leaning the axle back or forward, what sort of four bar or wishbones are you using? With a four bar with adjustable ends you lengthen the lower bars or shorten the upper ones to gain caster, just the opposite to lessen the caster. If it's a split wishbone or wishbone you need to drop the rear mounting at the frame to gain caster, raise the mounting to lessen the caster. Setting toe is simply measuring the distance from tire to tire in the front, then in the rear and adjust the tie rod by screwing it in or out of the tie rod ends to change that distance. A 1/8 to a 1/4" toe in is your typical toe for a solid axle front end.

An "A" body, refer to LATECH's post. :D

Do you have the tools to know what caster and camber you have?

Brian
 
#4 ·
Semantics. The front end in question is under a 40 Willy's with a S-10 front end. After further scrutinizing I have found that I am probably going to have to replace several parts on the passenger side before I can make any sense out of the measurements that I am getting. It seems that something has hit the lower A arm hard enough to bend the front part of it in a good 11/2" and so I am going to need to find out how to remove the lower A arm without the spring and related parts flying out due to spring tension. I also plan on replacing all the moving parts at the same time.
 
#5 ·
There are many different ways to adjust alignment and knowing what exact kind of suspension we are talking about makes all the difference in the world.

You need to look at the frame mounting points for the control arms, that is where you can get things all out of wack.

Here are some examples of how you can measure off what you have.



It doesn't matter than your suspension is different than the drawings, the same principles apply. Just find "control points", spots that are the same on both sides that are straight, this may require measuring back like in this example to be sure the points you are using up front are correct. Someone putting the front frame clip on crooked is always a possibility.





There is always a chance that the frame is bent also. An S-10 Frame bends VERY easy right behind the rear control arm mount. If the wheel gets hit, the leverage is tremendous and the control arm pushes back on the frame that is already "bent" because that is how the frame is made with a curve right there behind the suspension, right? So like the aluminum can that bends VERY easily after you put a small dent in it, that frame bends very easy at that factory bend behind the control arms. So you need to look at that carefully. Cross measure the mounting points for the lower control arm to see that the damaged side isn't in towards the center of the frame, that is how they bend when the wheel is hit. If the control arm is bend it is almost a sure thing that the frame is too.

Brian
 
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