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Discussion Starter #1 (Edited)
I finally got around to start the alignment on my 66 coupe. I bought a Longacre digital gauge. I thought it would be easier than the bubble kind. I have played with it about an hour or two. My problems are driving me nuts. I have a question about how to read positive and negative on the gauge. If you look at the picture, there are 2 arrows, one one each side. Either pointing up or down. How do you tell if it is positive or negative. The gauge only shows the number, no + or -

Another problem I am having is the front bolt will not loosen so I can remove or add shims. I have to raise the car up in the air before I can remove the front set. I am afraid that by raising the tire off the ground changes the way the tire sits each time so I get a different reading every time. Is there a simple trick I am missing?

Thanks for any help.

Homer
 

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When I did my alignment, I had a hard time getting the space necessary to add/remove shims. The upper control arm bolts were really tight in the hole. I finally got a LONG wrench inside the UCA area between the UCA and the frame rail, and gave it a mighty tug. That did it, and went from there.

Can't help you with the gauge reading as I use a bubble gauge.
 

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Read the instructions, or when in position on wheel, move one end away from wheel and observe whether it increases or decreases.

On one car, the bolt splines were not enough to hold it in place while loosening or tightening the nut. Had to finagle a wrench under the control arm to keep from moving.
 

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With the wheel turned and better access, I just stuck a BMF screwdriver or pry bar to move the control arm out slightly to install shims.

On my bubble gauge if I'm on the left side, I turn the wheel to the left 20°, zero the gauge and turn it 40° or 20° to the right and the caster number will show.

It's pretty easy to tell if you have positive or negative caster just by looking at the wheel when turned. If you're on the left, turn the wheel to the left. For positive, you can see the top of the tire is leaning back. Negative, iti leaning to the front
 

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Looks to me like the arrows are telling you which direction each end of the level is tilted, ie in your picture the left side is down and the right side is up a total of 2.9 degrees.
 

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Yep, the arrows indicate the tilt of the gauge and consequently the tilt of your tire. To keep the tires neutral after raising and lowering, I folded up a couple of heavy trash bags and put under the tires. After lowering, bounce on the front end a few times and your tires should be sitting about where they're going to.
 

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I don't know about everyone else, but I think they should fire whoever it was that chose those symbols for that display. For me, those arrows do not show the actual direction of tilt but instead the direction you would have to move it in order to achieve "Level". Look at their diagrams, the reference to "Level", and the arrows being displayed.
 

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Bubble caster/camber gauge is much easier to use. Don't need no newfangled digital contraptions.
 

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Are these tools easy to use? How do you get the car to sit at a consistent ride height after adjustments? Is it just just a matter of cycling the suspension over and over and checking the your alignment tool multiple times?
 

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Are these tools easy to use? How do you get the car to sit at a consistent ride height after adjustments? Is it just just a matter of cycling the suspension over and over and checking the your alignment tool multiple times?
The tools are fairly easy to use, once you know what you are doing.

If you have stock type rubber bushings, never tighten the suspension while the car is on jack stands. set the car down with the weight on the tires, then tighten the bolts. When aligning, after you make an adjustment, roll the car back and forth, this will settle the suspension. You may have to make adjustments several times because the adjustments are all interrelated. You may have to sort of sneak up on the adjustments to avoid over adjusting. It's just trial and error for the most part. Like anything that's an art, the more you do it, the better you become at it.
 

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I don't know about everyone else, but I think they should fire whoever it was that chose those symbols for that display. For me, those arrows do not show the actual direction of tilt but instead the direction you would have to move it in order to achieve "Level". Look at their diagrams, the reference to "Level", and the arrows being displayed.
Looking at the instructions again, I believe you're right. I think the easiest way is to remember that you want the arrow closest to the wheel pointing up. That will indicate negative camber as well as positive caster when the unit is in caster mode.
 

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Discussion Starter #13
I went to that link that was posted and found the instructions. I did not get all 3 pages that are on the site. At least now I have them.
I am still confused by the wording on page 2 and 3. One says this little icon must be on the display screen when normal (or caster) use. Push zero if not on. The next page leaves out the (or caster). So when I measure Camber the icon must be on the screen. But the instructions say move the wheel 15 degrees, level the gauge and then hit zero. The little icon never comes on when measuring caster. But it says it has to be on. After you move the wheel and level the gauge, it says hit zero. Now 0.0 should be flashing. No icon is on. So it says to hit zero to make it come on. When I do that, the reading goes back to what it was before I zeroed it. Should the little icon be on when measuring caster?
Any body have one like this? What do you do when measuring caster?

Thanks for any help.
 

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They do have videos on using the gauge. Hopefully this helps. If the link doesn’t work, try googling.

 

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This might help... but of you've used custom parts....your settings may be different. These are STOCK settings....
 

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I think its important to understand what castor and the process is doing if I can say this without sounding condescending. For those that already understand, just ignore this post, for those do did not, as I did not when I started doing my own alignment, it wasn't until I studied Huskinhano's wonderful post and a few other articles that I understood this simple geometry problem that it all fell into place.


Negative Camber is good and indicates to top of the tire leaning in towards the center of the car. Castor is about adding negative camber as a function of turning the steering wheel. As you turn the weighted wheel into a turn e.g. drivers side on a right turn, the tire should lean into the turn more as turn angle increases. Negative camber is increasing more as a function of the turn angle as castor value increases. So when the driver's wheel is turned left 20 degrees, front of the wheel sticking out from under the fender, you zero your camber measurement. Then turn it in or right to 20 degrees, your reading should tell you if the camber is more or less than it was turned out.



I use a simple digital level with a magnetic mount slapped on a steel rectangular tube that fits between the upper and lower lips of the wheel. I have the same problem understanding the number, so I put the level in place and lift the bottom off the wheel simulating adding negative camber and see which way the number reads and assign that mentally to negative camber. I have to do it for each side. That is one way you can ground yourself on the readings of your systems e.g. arrows...



Good luck!
 

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Discussion Starter #18
What am I doing wrong? I watched the video and did it just like they said. Every time I check it after adding or subtracting, it is different. I will check it and bounce the car a nd check it again, different. What now?
 

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After each adjustment, bounce (set) the front end and turn the wheel side to side. Do it the same way and order after every adjustment.


Mark
I'll add to this that when I was adjusting my alignment, I found I actually needed to drive the car down the road going in and out of some parking lots to get a good bounce and let everything "settle" then come back and check it again. Obviously in doing so I was also turning right and left making sure all the steering was being moved.

Allen
 
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