Precise Alignment with a Digital Level

Do you hate alignment shops like I do? They act like they are high priests of the dark arts or something, then in a conversation, it becomes clear that most of them only ready fancy displays and screens having no idea exactly how any of those numbers affect a cars handling! (breath)

Ok, now that that is off my chest. I have searched for a shop to align my stuff here and there over the years and they just don't want to play with a 40+ year old vehicle anymore. The last guy told me flat out that his machine had no specs, ( I said I have the specs) then he says his guy would have no idea how to adjust it (I said thanks, C ya!).

Here is a play by play for measuring any car's alignment. I expect you already understand how to adjust these things and you will have your own specs, so pay attention to the means and I'll show you the end. Remember to set the brake once parked and be responsible you your own safety. (that was my dsclaimer)

First, there is an order in which you should perform an alignment, assuming everything is close enough to be fairly road worthy to start with. If you just assembled the thing, get it all close before you get detailed. First, set the Toe (in, or out as you wish), then set the Camber, finally the Caster. Recheck everything. Adjusting Caster or camber affects Toe, adjusting Toe messes with the caster measurements, etc.

So let's get set up. You need a level place to play and you need all your tire pressures set. Loosen all the tie-rod sleeve pinch bolts before you pull the car into the driveway the last time so that you don't need to jack the car up after settling the suspension with a short drive. Next, you will need some kind of toe plates to make life easy. I use a small piece of sheetmetal with some oil under it. My floor isn't very smooth, so this is on top of a larger sheet. This lets the wheels turn easily when you adjust toe and measure caster. Roll the car onto these so that you don't unsettle the suspension. Jacking the car up will add all kinds of variables to screw with your measurements.


Next, set up some stands at the front and rear with string parallel to the rockers, up close, but not touching the tires, level front to rear.


I measure off the pinch weld with a very good rule to make the string absolutely parallel to the rockers.



Once the strings are true, you are at a great place to check the rear axle. Mine was 1/8" to the passenger side. Acceptable.



Now set the toe, measuring off the tire fore and aft of the spindle, just as you did on the rear tires. Setting toe is as much about the method as it is the number. The toe plates are crucial here. Begin by setting the steering wheel straight ahead. Remember that there is slack in the steering. You want equal amounts on either side of center when you do this. Now measure, then adjust. Before measuring again, you need to recenter the steering wheel. My wife came in very handy for this. Double check everything before you tighten the tie-rod sleeves back down. You should be able to reach them without jacking the car up. If not, it can wait until you finish caster and camber work. My measurements when finished had the tire off the string by 9/16" aft & 11/16" forward for 1/4" toe-in. Remember that this is a very dated way to measure toe. Today they speak in degrees. On my wheel diameter, this is less than 1 degree. 12" from the spindle, 1/4" is about 1 degree.


Now you can measure Camber. This is by far the easiest. Wheels straight ahead, nothing tricky, place the digital level against the rim holding it truly vertical. Negative camber has the wheel leaning in at the top. Zero to -1 degree is OK for my case, so I am good to go. It's shims at the A-arm mounting if I had required a change.


Now comes the fun part, Caster, and this is why we need a digital level. You can buy fancy Caster/Camber gauges that do the math for you, but I'll show you what they don't want you to know. (I got lucky and found one that spelled it out )
Draw a K on the floor. The back needs to run 12" fore and aft of the spindle center-line and be exactly parallel to the strings set up earlier. You didn't bump them, did you? The legs of the K need to be at 20* off the back. This will be 4 3/8" out at 12" from center.


Now the fancy guages are particular about the order you measure. My method is not. My method presumes that you have positive Caster where the fancy tool will detect negative Caster by their paticular order of measuring. The math is simple. Turn the wheels 20* to one side, measure Camber (#1), record how far from 90*, turn wheels 20* in the opposite direction and measure Camber again (#2), record how far from 90*, Add #1 to #2 and multiply the sum by 1.5 to get your Caster reading. In this process, the 20* to each side and the 1.5 multiplier are very specific and related. Change these and the math goes into land of the lost. You will have to ask your kids Trigonometry teacher why this works. I get it, but I ain't explaining it!


So here we go, turn wheels 20* one way (use the K you drew on the floor to eye ball it carefully) and measure Camber, again, the level MUST be truly vertical.




Turn the other way and measure again...



Do the math...



After a few adjustments and measuring many, many times, I equalized both sides at just over 2* positive Caster. OK for now, but I'll get ot up over 3* when I find my 1" wrench to shorten up the strut rods on the lower arms.



So there it is, precise alignment measurements with a ruler, some string and a digital level. My trusty assistant is quite pleased that her steering wheel points in the right direction now and the car stays in one lane when you take your hands off the wheel. It no longer pulls to the left when you get on the brakes and I am sure the tires will be happy for many miles. Best of all, I have no reason to waste and afternoon handing over twenty dollar bills to that dumb kid with the fancy readouts on some expensive machine!

 

Whoa... you lost me at the chalkboard... but it wasn't that hard!!

 

Subscribed!

 

well done! thank you.

 

Not wanting to be a smartass but your #'s 9/16 off the string and 11/16 off the string would be 1/8 toe, but wouldn't that be 1/4 total with both sides added together?, Maybe I'm wrong ,school me if I am. Thanks Good tech tip.

 

awesome tech.. I went through the same here last spring.. one guy said my car was too low for his machine.. two other places weren't interested. luckily I found a drag race guy that seems to have done an excellent job...

he was expensive.. but good..

We took a short "spirited" drive after the alignment.. as I drove and I talked about how the steering felt 'different" he was able to explain Why and how (based on the adjustments he had made).. I wish all mechanics had this type of curbside manner..

 

Great tech!Stashing this info for later,subscribed.
Thanks for posting.

 

I proofed it 5 times just for smart asses like you!

Thanks. Corrected.

 

Great article, thanks for taking the time to post it. I roughly set the toe in on my 63 with a 2x4 measuring the tread at the front and rear so it would'nt chew the tires up on the way to the alignment shop. Next project, I'll definitely use your method.

 

That's awesome - thanks for posting! Makes me wonder if it'd be worthwhile to get 2 strips of steel and predrill your string holes in there for faster/easier setup. Or am I over thinking things?

 

This is great tech. I've never been to an alignment shop.

I've always done my own and now the digital level has really made the operation more precise. I find use for a framing square, too. But any method that gets the geometry right is the right way.

I do have to mention that setting the toe should be the last thing. If you change camber or caster it will change the toe. So get the toe in the ballpark first and then come back and do it again as the last adjustment.

 

cool article scotty! why so much toe-in though? just curious. also, how critical is the order of operations? dealing with all the alignment crap i just went through on my ranchero, i was told by a couple old timers that you set camber first, then caster, then toe.

 

Just curious does having camber in the wheel affect this measurement or do you need to re zero the level in such a case in other words if you have negative camber of 1 degree on the digi level should it be zeroed to that before doing this procedure ? I did it both ways and it was very close within .3 deg when rezeroing the level . but would like to hear if your zeroing ? what I have found with this method though theoretically right to hold the level basically perpendicular to the ground can be tough to obtain accurate measurements I feel in principal this is right but in practice it leaves lots of room for error .IMO Ive tried it several times and honestly feel its difficult to obtain the level sitting on the wheel square and perpendicular to the ground but I feel it would get you close but not perfect .

 

You're paying attention. No need to zero the level on the wheel's static Camber. We are actually measuring a change in Camber, then multiplying that by 1.5. measuring the right side wheel, turn it to the right and it will face down, toward the rear, positive camber. Now turn it left and it will face up, toward the front, negative camber. Since the wheel passes 90*, you just need the difference on either side, added together.

I'm no math scolar, so I can't explain the 20* and 1.5 multiplier. I know it extrapolates the full range of rotation to measure the change in Camber. If you could move the wheel all the way to 90* off center, both ways, it would register Camber to match the Caster angle of the king pin axis. (don't confuse this with king pin inclination)

I really did get lucky one day googling all about Caster/Camber guages and found a site that just mentioned the math function performed by an additional button on their tools. Aside from that function, it's a standard digital level.

 

Great tech!! Very well done!

 

Excellent tech Mr. Scotty.

Now I need to hacksaw my 4' digital level to a useful length.

Fwiw, you can stack the very short digital levels on a standard - and straight - level for those times when you want to check level on long things.

Rubber bands or tape will hold them together just fine.

 

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I'll be at this for my A project soon..would like to see one of these tutorials for the Solid axle set ups..

caster and toe are all i can set because camber is preset by the solid I beam axle.
what do you do when your wheel and tire combo do not allow you to lay a string across them evenly? (wider out back than in front)
Im learning ,so if these are ignorant questions..its because ,, im learning

but as you mentioned..no shop(in my area) is going to do an alignment on a 1928 hot rod
and besides, i need to learn how to do it myself anyways

 

Granted, setting camber on a solid axle at home would be tough, but a little extrapolation from what Mr. Scotty wrote would cover the rest.

Once you find or can adapt to a flat spot, the digital level would measure caster just fine.

More than a few solid axle hot rods are running around with the toe set via tape measure and a line marked on the center of the tire....

 

Finally someone who can think outside of the 50,000 dollar computerized alignment box. Congrats.
I use extra long king pins, a plumb bob and a degree wheel when making my tube axles and aligning them. I get lots of flack from "Experts". ("Expert" is someone who knows everything but has done nothing) Back in the day i did alignments at our dealership with a device made by Snap On called a Racealigner . No computer and very very very accurate. It help me to understand much better what was going on .
I applaud your method and you post. Well done! Thank you.
Don

 

just did my 64 chevelle ....old school style with a tape measure and a degree wheel... went 115 saturday night and my nephew says its easier to drive than his old g body....

 

I was fortunate to work in a couple of shops and was permitted to do custom alignments when we had the opportunity. I've done stock cars, drag cars, old cars as well. Owners often handed me a set of specs and I just followed it. I've had trouble getting stock cars off the rack with a 1/2" of toe-out though. With the new 4-wheel systems, the would be lost if a car came in that wasn't in their computer.

Great tutorial though, simple but effective and easy to understand. I've done work on garage floors with the Snap-On turntables, magnetic spindle gages and toe trammel bar that was amazingly close when I put it on a real alignment rack afterwards.

Bob

 

the "too low for my machine" excuse is a cop out..so what, they dont do corvettes? Miatas? other very low production cars?..
the alignment guy that spewed that rubbage to you is a tool. and its a good thing too because i wouldnt want his lazy ass working on anything of mine anyways

if he would gain a brain cell he would be able to get your car up on his equipment with a few pieces of 2x12 or 2x10's layed flat so you could roll up onto them as you came onto the machine..this is what the alignment shop did for my 53 chevy..always more than one way to skin that cat

 

Thanks Guys. I appreciate it. I didn't dream this up though, I just dug enough to find out how the new race car tools work. I'm glad you will all get some use out of it and get away from the retail circus.

C9, you are right on, however I have been looking at how to measure my solid axle project and was lacking confidence in every option. King pin inclination and weight loading are among some of the factors that affect caster on a solid axle. This method will measure the net caster on any axle, even beams and tubes. Yes, adjusting one of those can be a trick, but identifying the problem is half the battle.

 

Just clipped the instructions

many thanks!

 

I answered this one last night but the server was acting funny. Looks like my reply was a casualty.

You can do them in any order you like, realizing that you will need to make a pass back through and check everything. What I came up with is that the Caster measurement being so sensitive to the camber and angle of turn meant Camber came first. Reading Camber accurately expects Toe is already set, so set Toe first. The key here is to note the severity of your changes. Big changes in any single setting WILL affect the other two in almost any car. Double and triple check stuff to keep an eye on what's happening. Working the tools and reading the numbers myself, I understand the relationships far better now than I ever have.

Why so much toe-in? I have been replacing the tired front suspension wear parts over the last few months. 1/4" was what it took to have good manners. Now that it has new everything, tie-rods yesterday, it may be fine with less. It isn't scrubbing tires and coasts beautifully, so 1/4" isn't bad on these tires. I will play some more along the way.

 

Thank you! I hate alignment shops as much as you do, and avoid them as much as possible (sometimes even at the expense of my tires and handling).
I've not only bookmarked it, but sent it to all my friends.

 

usually set the toe to 1/8", I think this is to allow for the spread that occurs when
the slack comes out of all the joints tying the 2 wheels together. Don't hold me to that slack businessl, that's my own thoughts right there.

 

a local shop told me that on a couple dropped trucks.....went back to the shop and switched to a set of old tall tires and took it back no issues then..... now as far as doing my old race car....he made me put it on the rack.

 

Good tech post. Having gone to the local junior college for several classes, front end being one of them, I find that just being armed with knowledge is a big help when dealing with shops. Luckily we have a great and conscientious front end shop in town that I refer folks to, and I've had positive feedback from my friends. After reading your horror stories I feel we must be truly blessed!

 

Nice tech. I've been doing alignments for almost 20 years now as a tech on a computerized machine. I learned on sliding control arms/shims adjustments , some guys coming into doing it now would be kinda lost unless they had instructions on a machine. I guess I never had to do it the old fashioned way .

As long as the rocker panal is square/parallel to the centerline of the frame or the rear end is square this would be a pretty good deal.