Home alignment setup

[JRouche]

Hey guys.. I have finally got all the suspension parts in and fitting. Air ride shockwaves in, control arms done, sway bar swinging clear of everything, new parts on all of it. Brakes are bled and now I gonna tackle the alignment.

I have read all the books and have a grasp on what needs to be done. First Im gonna prep my floor. Make sure I have a level surface. Hopefully Im not too far off with the floor, I dont want to spend much time using shims to get four pads that are level. Id love it if after I check the floor its good to go. Prolly not gonna be the case with my luck :) I have some nice turn plates that move in all directions. And I have some rear tire plates to level the car out due to the turn plates.

But besides that, the area prep work. I want to check for front end parallelism. So I can get the front wheels pointing in a forward direction before I check the Toe then work on the camber and caster. Then of course work back and forth between the adjustments as I change one to equalize all of the numbers.

But Im a lil confused, the starting point. ... How to get the front tires running parallel to the car, or more to the fact, parallel to the steering rack. So My first step I think, should be to get a parallel line set up beside the car that is parallel to the car and the rear. Then measure off of that to get my front tires inline. And work off of that.

So my question is. Am I going about it correctly? What I think I need to do is center the steering rack (I have that already) then once that is set have my parallel line along side the car to measure from to get the wheels referenced from that line for a rough forward pointing of the tires. My tie rod ends are installed for a really rough guesstimation of parallel right now. And the control arms are set according to that number so far.

What I would like to here is if anyone has done a home alignment before. When there is no decent starting point. I have originally straitened the wheels by measuring off of the cross member (a determined center point), and measured out to the steering arms on the spindles to get an equal number and adjust the tie rod adjusters while checking for toe in or out to align the wheels for a zero toe. But Im not sure if that is the correct method. I dont mind running a line from the front to the rear to align from that. I am ready to drop some anchors in the concrete floor to attach a fixture to string a tight stainless steel wire that will be parallel to the car. But is it acceptable to measure off the X-member for a center line reference and adjusting the toe that way?? I have toe plates so thats not an issue.

So Im at a loss. Do I need to run a reference line to measure from ( not a problem if so) or can I just reference the steering from the X-member then work all the numbers off of that.

My plan??? Get the steering so the tires are running straight ahead (zero toe) with the rack at its center line. Rough in the camber with the adjustable upper control arms and shims. Take my caster to where I want it. Re-check the rough camber. Adjust if needed. Look at the toe and get it back to center. Dial in the camber for where I really want it. Look at the caster. If its still close Ill live with +/- a half a degree there. Then fix the toe to where I need it. Re-check the camber (shouldnt have change much) and lock it in then double check the toe and lock it in...

Oh, and I have my numbers that I want to run for toe, camber and caster.


Whadda you think????? Gimme any and all the input you have. This is new stuff for me so ANY advice is appreciated... Thanks ahead of time for any input.... JR

[a67]

For strings you can use monofilament fishing line. But I find strings to be a pain. They are always in the way, and even a slight bump on the stand holding them or a bump on the string can move it.

If you are confident that the rear is square to the car, then use a laser and shoot it down the side of the car about 3" out from the rim. Use a small steel rule (6" works) and measure from the front lip of the rim to the beam and the rear lip of the rim to the beam.

Do this first at the back rim to square the beam with the car. I also place the laser level at the rear of the car pointing forward. This keeps it out of the way.

Once the beam is square to the rear rim can then use it to square up (toe setting) the fronts.

Make sure to have the steering wheel perfectly centered and best to clamp it so that it doesn't move.

Bob.

[yanniz]

I always do it as you say with a reference line that I know is parallel to the car, you can use laser and go off from the rear of the car or any other means....

I use the Fasttrax tool and works great....

The way I do it, I set the camber first....then on caster you will need to take your measurement at 15 deg out and 15 deg in.....before adjusting the caster, I turn the wheels in straight ahead so that I can keep an eye on camber changes....I do toe at the very end...

once you figure out how to do it, it will be straight forward....usually it takes me less than 1 hr to get this done, but the adjustable SPC arms help a lot vs having to deal with shims et cetera....

good luck...

[Norm Peterson]

It is possible to work with a floor that's slightly out of level as long as it's flat. You have to keep in mind that the cambers that you measure and the casters that you compute will need to be corrected to the actual vehicle attitude. Say the floor slopes 0.1° from one side to the other. That means that -0.5° measured for the wheel on the 'high' side of the floor is really at -0.4°, and -0.5° on the other side is really -0.6°.

From working with a car in which rear toe is adjustable and another car in which rear toe is not adjustable but not zero either (even though the thrust angle is pretty close), I wouldn't put too much faith in a line determined by assuming that any rear wheel is ever parallel to the vehicle centerline. Parallel strings is still the better bet. An adaptation of the SmartStrings approach is one way to ensure that the strings are in fact parallel. Then you can offset the strings from the front and rear wheels, keeping in mind that front and rear track dimensions probably are not identical.

Starting from scratch, I'd probably work rough caster, rough camber, rough toe, then caster, camber, and toe. Remeasure and iterate caster, camber, and toe if necessary. Caster adjustments seem to affect camber more than vice-versa (why you'd do caster first), and "final" toe adjustments have hardly any effect on the other two (why it's saved for last). BTW, make your caster sweeps for the left side and right side independently of each other. At 15° or 20° of front tire steering, Ackermann effects are creeping in, and the 20° that you work to on one side could be a degree or two different on the other (which makes the assumed factor for getting caster from cambers inaccurate and the caster won't be quite what you think it is).

Suppose you don't get the strings quite parallel to centerline. I think what that mostly means is that your steering wheel might end up a little off center on your test drive. Toes should be close enough, since they're still referenced to lines that are parallel, and close enough to being parallel to car centerline that - for the tiny amount of steering involved - Ackermann effects will be essentially nil. So you might have to adjust one tie rod longer and the other shorter by the same number of "wrench flats" a couple of times (this can even be done during your test drive, if done with a little care). Theoretically, equal and opposite tie rod adjustment will hold your toe setting, but in practice you probably won't get them adjusted quite equally. So you'll probably want to check the toe one more time against the strings after you're happy with the steering wheel position.


Norm

[LSx_88_Ciera]

Agree with A67 on using the rear end for reference and using laser pointer. That is how an alignment machine does it. To verify that the rear is square measure from hub center to LCA rear pivot point on each side and compare.
Set your camber and toe to your desired spec and use caster adjustment for road crown compensation. I go .3-.5° more positive on the right side.
After you make caster/camber changes jounce the front end a couple of times so it will settle out.
Curious is this going to be a final alignment or a get it to the shop alignment.

[Norm Peterson]

The difference between alignment rack equipment and various DIY methods here being that with the alignment equipment you compensate the alignment heads/targets and get readouts of rear wheel alignment measurements. One DIY equivalent is parallel strings and a camber gauge, which is one of the simpler ways to determine if either rear wheel flange plane is anywhere near to being parallel to vehicle centerline.

I'm sure that in some cases, rear toes really are pretty close to zero. But due to axle fabrication tolerances, there is no guarantee that they even start out that way. Never mind what might possibly happen during a few years in service.

The rear wheels on my '79 Malibu have sat at -0.5° camber and nearly that much toe (+toe, so it's toe-in) for as long as I can remember. Probably since 1986 when the whole axle had to be replaced. No way could I ever sight along or measure offsets from those rear wheel flanges and hope to end up with a line anywhere near where it needs to be. Or front toes anywhere near where I intended them to be.


Norm

[JRouche]

Some great info guys!!!!

Basically I was wanting to set up some lines so I could have a parallel referance of the car to transfer the lines to the front wheels. I put in a full rear quarter frame for the 4-link in the rear. I think I did my install correctly. But for the lines I was thinking of taking measurements from the frame rails to the lines (as far fore and aft as possible) and comparing them to the rear wheels (for axle fore and aft displacement) and the pinch welds of the car body along the lower section (the rockers).

Why so much work. Well, just to double check the work I did before, to see if the rear end is square to the body, Im hoping it is. And to have a verified reference from the rear and the body to carry on to the front. Then work from that reference.

I like the monofilament idea for lines but after using plastic lines and seeing how they can be easily moved I was thinking of using some of the 1000s of feet of SS wire I have on hand. What I will do is map out the floor (yes, checking for flatness and level, side to side and front to rear) and mount some red head sinkers in the floor to bolt some homemade uprights to. The uprights will allow me to tighten the wire to its max straining point before breaking and still have some detailed adjustments to essentially make a parallel box (minus two sides) to set the car in.

And lasers would be nice. But by the time I order them I think I can map out the floor and set some sinkers in and weld the uprights. The lasers would be a nice addition to the tooling but money is a question and I really do enjoy making up some fixtures.

Now. After rigging up some parallels (they will be far enough out from the wheels for clearance) I am gonna move the front wheels to parallel just to get them close.

I wanted to work on the less critical specs first. In my case I think its the caster. I can set it anywhere between 0 and 6* positive. I am shooting for 3* right now. Three degrees is not the best for camber gain. When I checked it statically (wheels up, no load (air springs)) 5* of caster gave me the best camber gain for the travel I have. But I have manual steering and I dont know how 5* of caster will be on the road. I dont want too tight of a steering.

So Ill set the caster for 3*. Then set the camber after seeing the changes the caster makes. My toe will prolly be way out at that point so Ill pull it in to zero, for the time being.

Ok.. I have another issue. Bump steer. I have some Baer tracker tie rod ends. So Im gonna have to deal with checking that adjustment. Im gonna do that after I have the camber set. If it turns out that I need to shim the tie rod ends up or down for BS then Ill readjust the control arms for that change too. I dont think the shimming of the tie rod ends will affect the camber.

Yeah, yeah.. It sounds like alot of checking and changing. But to be honest, I dont mind it. This is my lil retirement project car. I dont mind spending a few days on the alignment..

And yup, this is for a final alignment. It wont go to a shop for a proper alignment. I think I would have to be under the car with the tech just to show what I wanted. Might as well do it myself.

And this is gonna be a straight up alignment. No tweaks for road crown yet. If it becomes a problem later with pulling then I will tweak it for crown...

Thanks for all the input guys...... I appreciate the help!! JR

[David Pozzi]

For a first time alignment you can first establish a center line under the car. Drop plumb bobs-down from measured center points front and rear, run a string line under the car front to rear to establish an accurate centerline. Measure out from the center line to establish your string lines at axle height along each side of the car. It is much better to bolt or clamp a piece of tube across the front and rear to hold the strings. This is how the Indy car guys do it at the track, and you can jack up or move the car with this setup and not have to move the strings. On a leaf spring car, a straight edge or piece of tube can be placed against the sidewall of the front tire and you can measure or sight in if it's parallel to the rocker rails of the car. This is how I used to do it. Lately I've been placing a 2' laser level against the side of the front tire and pointing it rearward. It either hits the rear tire edge, or if it misses it, I place something up against the rear tire so the laser can hit it. This helps me set the front wheels pretty close to straight ahead when taking bubble gauge readings. I like to set camber, then caster, then recheck camber, all with a quick laser check to keep the wheel pointed straight ahead, then I use the toe plates to set toe in. This usually get's me to within 1/16" steering wheel turn of centered.

Roller plate turntables are nearly a must to get accurate turn angles for caster readings. A small error in turn angle will mess up your readings. The car should have it's wheels up on 4" to 6" tall blocks to allow enough room to get underneath and reach the toe adjusters.

[JRouche]

Hey David, thanks. Good info!! I already have centerline hard points set on the front and rear X-members from when I installed the art morrison 4-link rear clip. I should prolly go off of those points. I like the tip on using a bar that rises and falls with the car during suspension changes. Thanks for the tips.. JR

[David Pozzi]

On a lot of cars like Formula Fords, Indy, and Can Am, with link suspensions. You have to jack up the car and unbolt a rod end to turn the rod end. This requires moving the car a little when you jack it up, so the toe strings are best attached to the car. If I'm just doing the front end on a Camaro that has no rear troubles, I just use circle track type toe plates with wheels on turntables. I hate doing strings if I can get by without them. I found some surveyor's plumb bob string that is bright orange, it works great for stringline.
David

[JRouche]

If I'm just doing the front end on a Camaro that has no rear troubles, I just use circle track type toe plates with wheels on turntables. I hate doing strings if I can get by without them. I found some surveyor's plumb bob string that is bright orange, it works great for stringline.
David

Gottcha... Im only gonna string it to find the correct front wheel "forward" number. The front end is completely loose now so I just want to get the wheels pointed in a decent parallel direction then do the front end alignment proper. Ive got the turn plates and toe plates for the real adjustments. Oh, got a neat wheel mounted setup for the caster/camber gauge for aluminum wheels that dont have a proper lip. Special tool for the aluminum wheels. More playing.

And yeah, Im prolly doing more playing than working. I could just do some simple measurements off the front end to set the front tires parallel to the frame. But I am double checking my welding from years ago at the rear also to see if I screwed up back then or not. See if I welded in the rear sub close to parallel to the car body. Kinda hard to see if its the frame or an offset of the adjustable 4-link bars though. I always question my previous work :) Thanks for the input....... JR