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      04-14-2021, 02:24 PM   #1
MadDog89
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Help me diagnose a possible caster angle issue

Ever since I got my car I've had a slight pull to the right, tramlining, bump steer and wheel shake between 40-50mph, smooths out after that. Passenger front side tires had inner wear, similar to negative toe wear. I check tire pressure, balance, torqued lug nuts to spec, measured camber and toe, brake wear is even, all seems fine. My worry is that the caster angle may be off since the previous owner did indicate the car has been in an accident on the front passenger side. My question is, would bad caster angle on one side cause above symptoms? Or is it more inline with worn parts?

Under the hood, I noticed strut mount had the pin missing on both sides and was adjusted, more so on the passenger side than the driver side, possibly after the accident. But again, camber looks fine on both sides. Any help or insight is greatly appreciated.
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      04-19-2021, 05:07 PM   #2
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Mileage? How did you measure your camber and toe? Did you check for any play with the control arms and tie rods?
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      04-19-2021, 08:31 PM   #3
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Quote:
Originally Posted by freedomfries View Post
Mileage? How did you measure your camber and toe? Did you check for any play with the control arms and tie rods?
106K miles, I measured camber with a digital angle finder. Toe by measuring distance from the front center of left tire to front center of the right tire, then again on the back of the tire. Both end up being the exact same measurement, figured tires are facing forward if that is the case. Caster I measured using the trig method: caster (deg) = (180 / 3.1415) * [(camber1 - camber2) / (turnangle1 - turnangle2)], that too was within spec. I think.

Best bet is probably going to an actual alignment place and getting it checked. Not sure how accurate my back yard mechanics measuring methods are.
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      04-20-2021, 10:05 AM   #4
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I guess the first thing is, yes, caster could be causing the issue you're seeing. But it could also be a bunch of other things. My first guess is that you might have a bent strut if the camber at the wheel looks the same on each side but the bolts are set in a different orientation at the strut top.

Take the car to an alignment shop and have it checked. In particular, check the "included angle". It should be the same on each side. Its basically the angle between the strut and the wheel mounting face. If its off, it will indicate that your strut is bent.

You will also be able to see caster in that measurement as well, and if the caster is dramatically off from side to side, it could be a strut bent in the fore-aft direction, or the tension arms being bent or worn. The tension arm controls the fore-aft location of the wheel, so if this part is bent/worn then the caster angle will be out of spec.

Lastly, toe is another common culprit, though inner tire wear is generally an indication of toe out and you'd see it on both sides and the car would wander, rather than pulling.
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      04-20-2021, 11:14 PM   #5
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Quote:
Originally Posted by rothwem View Post
I guess the first thing is, yes, caster could be causing the issue you're seeing. But it could also be a bunch of other things. My first guess is that you might have a bent strut if the camber at the wheel looks the same on each side but the bolts are set in a different orientation at the strut top.

Take the car to an alignment shop and have it checked. In particular, check the "included angle". It should be the same on each side. Its basically the angle between the strut and the wheel mounting face. If its off, it will indicate that your strut is bent.

You will also be able to see caster in that measurement as well, and if the caster is dramatically off from side to side, it could be a strut bent in the fore-aft direction, or the tension arms being bent or worn. The tension arm controls the fore-aft location of the wheel, so if this part is bent/worn then the caster angle will be out of spec.

Lastly, toe is another common culprit, though inner tire wear is generally an indication of toe out and you'd see it on both sides and the car would wander, rather than pulling.
Thank you, really quick what's the difference between wandering va pulling? I'll have to take it in to be sure. I know it's been in an accident. Just did a vin check and it actually says frame damage, ugh...
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      04-21-2021, 09:31 AM   #6
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Quote:
Originally Posted by MadDog89 View Post
Thank you, really quick what's the difference between wandering va pulling? I'll have to take it in to be sure. I know it's been in an accident. Just did a vin check and it actually says frame damage, ugh...
Wandering is basically random pulling in each direction, like it doesn't really want to go straight. A pull is consistent to one side, like you take your hands off the wheel and it steers right.
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      04-21-2021, 02:40 PM   #7
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Quote:
Originally Posted by rothwem View Post
You will also be able to see caster in that measurement as well, and if the caster is dramatically off from side to side, it could be a strut bent in the fore-aft direction, or the tension arms being bent or worn. The tension arm controls the fore-aft location of the wheel, so if this part is bent/worn then the caster angle will be out of spec.
Not to hijack this thread, but I too have mismatched caster on left and right wheels. I learned this when I had my car aligned after installing new tension arms and new struts. The alignment shop told me it was slightly off and 'might' cause the car to pull to the right on perfectly level roads, however it tracks perfectly straight and I haven't noticed any pulling or wandering.

With regard to the topic of this specific thread, I'm wondering after installing new tension arms and struts, what could be bent causing the offset caster? is it the subframe itself, or subframe mounting points for the tension arms?

Or could it be the lower control arm (wishbone?) The lower rearward control arms (wishbones) on my car look to be identical and original to my car, and I haven't replaced those yet. I can't see any obvious distortion but it's hard to compare without removing and putting them side by side. The knuckle also looks fine.
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      04-23-2021, 07:38 AM   #8
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Quote:
Originally Posted by MadDog89 View Post
Toe by measuring distance from the front center of left tire to front center of the right tire, then again on the back of the tire. Both end up being the exact same measurement
First off, you've measured TOTAL toe for the axle. Go back and box the car to get a toe measurement for each wheel/tire assembly independently; that will get you a more complete look at whether or not the setting from one side is far enough off from the other to be making a difference here.

Also, since your measurements were the same going from front to back of the tire that means you have ZERO toe, which exactly explains why you have inner tire wear.

Again, go back, box the car off, and add some toe-in to each front wheel to offset the wear. Start with a couple 1/32" at each corner until you find the sweet spot to match your driving habits.

As for pulling/wandering, not sure if I missed it but what are the conditions of the bushings, ball joints, etc. up front? Wear there could easily be causing random issues like this and with your mileage it would be best to swap them out regardless.
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      04-25-2021, 12:02 PM   #9
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Quote:
Originally Posted by FCobra94 View Post
First off, you've measured TOTAL toe for the axle. Go back and box the car to get a toe measurement for each wheel/tire assembly independently; that will get you a more complete look at whether or not the setting from one side is far enough off from the other to be making a difference here.

Also, since your measurements were the same going from front to back of the tire that means you have ZERO toe, which exactly explains why you have inner tire wear.

Again, go back, box the car off, and add some toe-in to each front wheel to offset the wear. Start with a couple 1/32" at each corner until you find the sweet spot to match your driving habits.

As for pulling/wandering, not sure if I missed it but what are the conditions of the bushings, ball joints, etc. up front? Wear there could easily be causing random issues like this and with your mileage it would be best to swap them out regardless.
I didn't realize that front should have some toe in, the inner tire wear is only on the passenger front tire. I will try the box method and see if I get anything. Eventually I will probably get some caster plates, to make it easier to adjust things myself without having to go to an alignment shop. Bushing and ball joints seem fine, but idk given the mileage its probably due for a new set of everything.
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      05-03-2021, 02:35 PM   #10
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So I took my car to get alignment diagnosed, the guy at the shop was hesitant to even look at my car saying that spacers are the culprit... Weird because I had issues before spacers and yes spacers possibly made it even worse. I told him all I want to know if my alignment is in spec. Just give me the damn numbers.
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      05-12-2021, 01:18 PM   #11
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Well, that puts the "could this be caster?" issue to bed.

Next up is getting front camber just a bit closer and adjusting toe all around.

For camber up front, push the passenger side in as far as it will go and remeasure camber on both sides yourself. Should be very easy with the pin already gone.

You've already got a good working knowledge on adjusting toe, so square the car, make a couple of adjustments (front and rear), and you should be good to go.

Anything else related to vibration/wheel shake/etc. will likely be solved with a good road force balance.
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      05-19-2021, 11:41 AM   #12
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Quote:
Originally Posted by FCobra94 View Post
Well, that puts the "could this be caster?" issue to bed.

Next up is getting front camber just a bit closer and adjusting toe all around.

For camber up front, push the passenger side in as far as it will go and remeasure camber on both sides yourself. Should be very easy with the pin already gone.

You've already got a good working knowledge on adjusting toe, so square the car, make a couple of adjustments (front and rear), and you should be good to go.

Anything else related to vibration/wheel shake/etc. will likely be solved with a good road force balance.
Finally got my alignment fixed, took it to a pretty reputable shop. Guy there had my tire on the road star and showed me how much it wobbled. Basically said my tires are shitty. He balanced all 4 adjusted alignment and it is so much better now. He also mentioned that the way my tire is could be due to worn suspension parts.
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