Massive caster variance Side to side

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RustyRatRod said:
The unlocked brakes allow the wheels to turn, which affects the caster measurement. If they are allowed to rotate, it's impossible to get a correct measurement. Not to mention, with the DIY caster gauges, what are you turning the front wheels with? The tire. With the brakes unlocked, you are severely affecting how caster is measured turning the tires using your hands. The proper way is to have the brakes locked and do the caster turn using the steering wheel, but that's about impossible to do using the DIY caster gauges. I guess you could do it with two people.
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This is where there is difficulty in understanding the difference.
This gauge:

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Does not stay in place the entire time. It can be removed and reattached. This gauge is used in a different manner than what is used on an alignment rack. Think of it this way: Turn the steering wheel 20 degrees to the LEFT and attach the gauge. After measuring, the gauge is removed, the steering wheel is turned to the right and the gauge is reattached, recentered and the caster is checked again. The gauge doesn't have to stay in place during the steering of the wheel. The wheel can spin 180 degrees and it won't affect the measurements because the gauge is essentially recalibrated each time it is reattached.
Again, if you haven't seen the video or used this tool, it may seem strange to you.
I once had a guy on the job that was one of those guys that loved new tech and stuff like that. I had to measure an opening to build a roof in between two beams. I told him to grab my tape measure and go up on the ladder while I got up on the other. He said..."I have a better way".
He pulled out what looked like a laser pointer and put it against the beam nearest him and aimed it at the beam nearest me. 30 feel, 11 1/8". Then we pulled my tape measure and got 30 foot 11 1/4". The tape had sagged a little in that span (Giving a false longer reading) so I figured that I'd go with his number and it was right. New tech sometimes does work.
Not always...I'm not a fan of using battery powered circular saws for heavy or extended cutting. They overheat and crap out.
 
Doesn't using this portion of the tool (circled below) to level it render any wheel rotation irrelevant? I have one like this, well I used to at least (a buddy's had it for a while now). When taking left and right measurements, you level the gauge for both first. Any wheel rotation is negated by that act. At least, it's worked fine for me.

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My point exactly. The bubble level allows for what equates to a reset for each time it is used to measure.
 
FWIW...I have the bubble gauge as shown above but instead of Longacre Racing on it, mine says Joe's Racing Products. Same gauge! I used several heavy thick plastic garbage bags folded over a few times as my turning plates. (They worked well as you could turn my manual steer avatar car with virtually no effort.)

Per the ibstructions, I attached the gauge to the spindle, zero'd it out with it at a 20 degree steering angle, then turn to 20 degrees in the opposite direction (total of 40 degrees) and get your reading. I tried it several times just to insure repeatability without making any adjustments. I found it highly repeatable so I was excited to get to set my alignment with my new SPC UCA's I got from Bergman's. Each time I made an appropriate adjustment, it showed up on the reading (meaning the reading showed what I had adjusted). I set the caster to +3.5 degrees on both sides and suddenly I had a car previously unable to be taken down the track reliably (it would go into this left/right porpoising mode unable to be controlled...scary!) to one that leaves dead straight and stays dead straight! So I have to believe that what I set using the gauge was pretty accurate. It sure worked for me!

Let me add though that I am NOT an alignment guru. Just sharing my experience I had with my avatar. I used this same setup to set the alignment on my show pony 71 Demon as well. It seems to have worked out fine there as well although that car was much more of a challenge given it's stock front suspension parts.
 
Check the lower ball joint measurement side to side
If it's the same then you have something bent, likely a spindle
 
One simple check is setback. Turn wheels in straight ahead position. Then just do a visual. See if the tires/wheels set in opens properly. With cross caster being so excessive, should be obvious. Vehicle should be pulling to the wheel that's pushed back or negative caster.
 
Going to throw this out there as the all-star one is the one use. Got caught up in the same type of reading issues but it was as kerndog post shows it was not following on right side start right out zero then back and left side left out then zero and back. Also I just tape my steering wheel at the top,go one and a half right, zero then three back the other way. Keeps the degree thing equal both ways from straight ahead.
 
andysauto1 said:
Check the lower ball joint measurement side to side
If it's the same then you have something bent, likely a spindle
Click to expand...
Brilliant. Like from the k? What referece point would i measure from? And ifnits different then its likely LCA.. why didit i think of this
 
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Best of 3 said:
One simple check is setback. Turn wheels in straight ahead position. Then just do a visual. See if the tires/wheels set in opens properly. With cross caster being so excessive, should be obvious. Vehicle should be pulling to the wheel that's pushed back or negative caster.
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Its pulling now to pass side but was not pulling before i effed with it at - 1 camber both sodes
 
Ok so.. its 33 1/2 pass side ball joint zerk to trans crossmemebr
Ans its 33 3/4 driver side
So pass side which is the effed up side is kicked rearward 1/4”. I bet the pivot pulled away on the pass side LCA..which makes sense because for more + caster u need the lca more forward and the uca more rearwad..
 
So looks like bush were poly
No clips holding t-bars
Lca pulled rearwoard away from pin
WhAt ecatly locaTes the lca from doing this? Im going with rubber moog. Also can anyone ID this strutrod.. 67-72 or 73+

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Ps thanks for all the replies helping me wrap this up in a day. God bless fabo and its deciples
 
I went ahead and aimed for 1.0 degree negative camber. The caster fell into line at 8.0 degrees I would have been okay with less but I’ll drive it and see.

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Both sides have the same numbers.
Setting toe with these plates.

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I got it to 1/8” toe IN.
Time to drive it.
 
Boduke said:
What uca gives 8 degree?
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DIY 21.jpg


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These are B body arms I have in my Charger.
I was able to get 5 degrees of caster with stock arms and offset bushings. Maybe my car is blessed. I have another '70 Charger that I'm going to do some alignment testing on. That car tracks straight but hasn't been aligned since I've owned it. I replaced the whole front stub in it in 2020.

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The drive with caster this high didn't seem to be unusual. The steering wheel returns to center all by itself...when I let go of the wheel in a turn, it spins back to center. It didn't return with such intensity before when it had 3 degrees. Otherwise, It steered and drove fine. NO squeaks from the poly bushings in the UCAs but then...I used lots of chassis grease when I installed them.
I'm learning how some cars may look like others but sometimes a frame rail is slightly forward or behind another, the UCA mounts could be a fraction of an inch forward or back compared to the other side. Small variations will affect alignment.
To get the numbers I got, I did have to shim the lower ball joint on the right side. Otherwise, with the high caster, I couldn't get the camber to where I wanted. This is no different than the other little tuning tweaks we do to get our ignition curves just right, degreeing a camshaft, carburetor jets or air bleeds, it is just tuning instead of assembling.
 
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