[egchewy]

Chewy: I also use the string method. Once you have "strung" both sides, make sure the string is the same height from the ground on both sides of the car all along the side, ie front, middle and rear are all the same, and that the string is at the center of the wheel. I like to measure at the rim of the wheel (after all that is where the alignment heads attach on a real alignment machine). Using the side wall may introduce variances, and exaggerate your true toe.

I also found a difference in measurement side to side as you did, indicating the rear is off to one side. I adjusted the panhard bar to make sure the distance from front wheels to string is the same both sides. You are only off less that 1/2 inch side to side. Measuring from the shock towers is probably not accurate...they are welded in place by a human! I would center the rear, or "square" it, relative to the front, and proceed from there.

Others may have other input, and I welcome any suggestions.

so if i'm hearing you correctly, I should be adjusting the panhard bar to center the rear wheels relative to the front wheels and not the actual frame of the car? have others seen this issue ?

 

[egchewy]

I use toe plates and measure referencing at the outer diameter of the tire tread. Look at it this way; if you measure the rim and set it for let's say 1/16" with a 25" diameter tire then mount a 30" tire the difference at the tread will be much different. OR---to go the other way, if you measure 1/16" using a 15" rim with 25" diameter tire and then install an 18" rim with a 25" tire the toe will measure differently at the rim even though you made no changes to the tie rods and the toe at the tires will be the same. In that case which of the measurements you came up with is correct? The one with the smaller diameter rim or the one with the larger? It's for this reason that I use the tire O.D. when measuring in inches and why modern alignment equipment references in degrees (1 degree is 1 degree no matter what the tire and rim combination).

That should be clear as mud just like discussing pinion angle


Jeff

yes jeff, this was my point exactly. i'll take the measurements from the outer diameter of the wheel. so part of my question remains...the 1/16" you measure is the total difference from the front to the back of the wheel and not from the line as measured w/ the string method, correct? as you toe the wheel in, the rear of the wheel flairs out, so the distance you turn the wheel in is actually less than 1/32", and more like 1/64", since the rear of the wheel is moving out as the front is moving in.
when using the toe plates, how do you know if both wheels are toed in the same amount? for example, one wheel might be toed in 3/64" while the other is in 1/64" giving a total toe in of 1/16". or does it even matter?

 

[hefbadr]

so if i'm hearing you correctly, I should be adjusting the panhard bar to center the rear wheels relative to the front wheels and not the actual frame of the car? have others seen this issue ?

Yes, that is what I'm suggesting....I'm hoping others can jump in to confirm or otherwise educate...

 

[egchewy]

OK. I suspect I'm doing something wrong. Trying to center the rear solid axle to the front wheels using a string method. String is stretched from behind rear wheels, touching the rear of the tire and adjusted until it just contacts the front of the rear tire. When measuring the distance from the taut string to the front tire, the DS tire is just under 2"and the PS is under 1". This suggests that I need to adjust the panhard bar to move the rear axle towards the PS about a 1/2"right? Lengthening the panhard should push the PS out and the DS in, right? Well, i have about an inch of thread showing on either end of the panhard bar and don't feel comfortable exposing more in fear of not having enough threads left inside the shaft. The pics are showing the distance to the string on the DS and PS as well as the relative position of the wheel to the shocks. You can see more distance between the 2 on the PS. THOUGHTS? Last pic shows how much threads exposed

 

[hefbadr]

Chewy: I suffered the same confusion you're experiencing right now. I just looked at my car: If your D/S is more that your P/S you need to move the rear to the D/S to reduce that distance. If you have 2in on the drivers side you need to reduce that by shortening the bar, which will move the rear to the left, and bury more threads into the bar. If there is any doubt, jack up the back end of the car, play with the bar and see what happens till you get a clearer understanding. Confused the crap out of me at first. Let me know.

 

[johnnybgoode]

Looks to me like you need to shorten the panhard bar and move the rear axle more towards the driver's side. I put a level across the rear tire (or cut a 2x4 to sit inside the rim lip) and measure from that through one of the wheel windows to the 4" round tube and get the measurements equal on both sides to center the rear. Are you sure your string lines are parallel to the chassis and square? They should be the same distance apart in the front as the rear. You can check for parallel by dropping a plumb bob off the center of the front cross member and then measure to your string lines from there to match the rear. Squaring up the car and doing the alignment is a fun process for me. Just take your time and realize you will be checking your measurements multiple times. Good Luck. Scott

 

[egchewy]

i'll try shortening the panhard. It made most sense to me that if the gap between the line and front tire was more on the DS, then I would need to move my axle towards the PS by lengthening the panhard. i'll try it the other way to see how it affects the gap.

 

[egchewy]

so the confusion continues.
i tried shortening my pan hard bar all the way to see what effect it had. as I suspected, it made the distance on the DS larger and the PS smaller, so now the DS distance to the string is over 2" and on the PS it's under 1/2".
this led me to take a look at my front wheels, thinking that maybe they weren't centered.
measuring from a set point on the shock mount on either side, I found interestingly that the outside of the DS wheel was actually about 1/4" further out from the frame than the PS wheel.
I double checked my front UCA and LCAs to make sure I didn't inadvertently attach them to the wrong places. And by correcting the discrepancy in the distances of the front wheels, I would actually make the alignment measurements of the rear axle worse.
Any other thoughts here?

I suppose I should verify that I adjusted to negative and not positive camber on DS

 

[rich grsc]

Stop screwing with the pan hard bar. Center the rear axle and leave it be. Move on to adjusting the front

 

[egchewy]

Chewy: I suffered the same confusion you're experiencing right now. I just looked at my car: If your D/S is more that your P/S you need to move the rear to the D/S to reduce that distance. If you have 2in on the drivers side you need to reduce that by shortening the bar, which will move the rear to the left, and bury more threads into the bar. If there is any doubt, jack up the back end of the car, play with the bar and see what happens till you get a clearer understanding. Confused the crap out of me at first. Let me know.

you might be mistaken by the pics. I'm showing the distance between the string and the front wheels, not the rear. so there's a larger gap between my string and the DS front wheel than the PS. I need to figure out how to move my rear axle towards the PS to make up the difference. I'm going to take richg's advice and center the rear, then figure out how else to make adjustments. I already tried lengthening my panhard to the max and there was still a bit of difference between sides w/ my DS still farther away from the string than the PS. Shortening the bar made this gap worse. I did find that my DS camber was pulled out of alignment ( -0.5* -> 0.0*) when tightening my locking nuts, so i'll need to pay attention to this as i'm tightening things down.

 

[egchewy]

OK. finally dialed in my camber and caster after 2 hrs of monkeying with it. it's amazing how much the lock nuts will pull your camber out of spec. I found that I had to set my camber to -0.7* before tightening the lock nuts to get it at -0.5*. caster is set at 3.5*.
now for toe. I was trying to use the string method to align my front wheels. I was stretching a string on a jack stand from behind the rear wheel, moving it in just until the string was touching the back and the front of the rear tire. while doing this, I found that my DS wheel was further away from the string than my PS wheel. I assumed that I had to move my rear axle towards the PS but ran of threads on my panhard to do this. I currently have my rear axle centered measuring from the shock tower tab to a consistent spot on each tire.
I finally figured out that my strings are not parallel to my frame. this means that my rear axle is off by a few degrees, leading to the appearance that my front DS tire was too far from the string. In other words, my rear axle is not perfectly square with the thrust line. I realize that there's nothing I can do about this without adjustable lower arms for my rear end.
I'll reposition the strings so they're parallel with the 4" frame tubes and proceed from here going forward.

 

[egchewy]

OK, per other forum members suggestions, I made some wooden jigs to measure my string to the 4"frame tube. My method of skimming the rear tires to line up my strings was flawed as my rear axle is not square with the thrust line. My jigs measure to the inside of the 4"tube since I have gas/ brake lines on the outside.

I adjusted toe until the front and rear of the front rim was equal. Both sides were the same distance to the string. Then I did equal turns on the inner tie rod until my toe plates measured 1/16"toe in.

Next question... any problems with my rear axle not being square other than uneven tire wear?
I'm about 1/8"off between the back and front of the rear rims.

 

[JKleiner]

... any problems with my rear axle not being square other than uneven tire wear?
I'm about 1/8"off between the back and front of the rear rims.

The rear axle not being square won't wear tires (unless the reason that it isn't square is because an axle tube is bent causing rear toe) because it's going to run straight down the road no matter what. What will happen if it isn't square with the chassis is that the car will "crab" or "dog track" (old Camaros and Novas with monoleaf springs were notorious for this when they sheared the spring center pin and the axle shifted forward or back on one side). The axle pushes straight ahead, the front wheels are steered left or right to correct and the body and chassis are not parallel with the direction of travel.

Here's a photo showing an extreme example; notice how the front wheels are steered to the right to maintain a straight ahead direction but we can see the left side of the car!

Jeff

 

[egchewy]

Sweet. So I'll look like I'm drifting all the time

 

[egchewy]

Working on my fitech tuning a bit. Idle air control setting was set way too high. Also need to adjust prime fuel shot on cranking. Took it out for a spin, first time since alignment. Apparently my wheel wasn't perfectly straight when doing my toe and I have my wheel clocked about 10* to the left to drive straight. I'll work on this again. Next up, removing my DS pipe to attach my outer footbox wall.

 

[CraigS]

10deg left is no big deal. Adjust the tie rods to fix it. SInce it needs to be steered left to go straight, you need to adjust so the wheels aim more to the left. Make the left tie rod longer the same amount as you make the right tie rod shorter and your total toe will not change. I always make a paint mark on the tie rod and the tie rod end so I can keep track of what I am doing. The rubber boot may tend to make the tie rod spring back when you remove the wrench. The jam nut may tend to rotate the tie rod end as you tighten it so you need to watch carefully. I'd start w/ 1/2 turn on both sides.