Fixing Thrust angle

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Gabriel Larson

Gabriel Larson

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I completely rebuilding my font end because of a pulling to the right on my 70 dart. Well now it drifts very slightly to the left even after getting an alignment. my Frames teacher at school is thinking it has to do with my -0.35 Thrust angle but he hasn't had time to look at it. could this be the cause and if so how would I go about fixing it? here's the alignment sheet.

5D0CE8CB-55AE-4AD3-BAE6-74DDCE28A610.jpg
 
Probably not. Try crossing the front tires.
 
Gabriel Larson said:
okie dokie will give it a try in the morning.
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Yup. It's free. It'll do one of three things. Keep pullin like it is. Drive straight. Or pull to the right. If it pulls right, I'd rotate it to the rear, because you found a pullin tire.
 
Bodyperson said:
Power steering?
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The only possible way unless something's wrong with the gearbox is, if the steering wheel is off center a good bit, the gearbox will have a tendency to want to "find center" when it is energized by the pump. Chryslers are a bit more sensitive to that, too.
 
RustyRatRod said:
Yup. It's free. It'll do one of three things. Keep pullin like it is. Drive straight. Or pull to the right. If it pulls right, I'd rotate it to the rear, because you found a pullin tire.
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When I was doing alignments, tire pull was almost always the problem after a good alignment.
 
RustyRatRod said:
Yup. It's free. It'll do one of three things. Keep pullin like it is. Drive straight. Or pull to the right. If it pulls right, I'd rotate it to the rear, because you found a pullin tire.
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I do like free haha I should know this because I work at a tire and do it all the time but I guess just like starting new projects
 
I can’t tell from the printout, is toe in degrees or inches?
 
Looks like you have .4° of cross camber and it would be set to pull left. Typically the max cross camber you want is .5°. It's in the correct direction to correct for road crown, but if you're driving on roads without much crown you might notice some pull to the left with that setting. You said it was only a slight pull, so, that could be part of it.

Also, it looks like you had them do the right thing and run positive caster, so I'm assuming you're running radials. But you also have positive camber? It's a small amount so it's not a big deal, but you'd be better off with slightly negative camber than slightly positive.

And if you turn your camera sideways and zoom in a bit it will be a lot easier to read that alignment sheet. :D
 
I think, on a perfectly flat road, the little amount of positive camber combined with the negative thrust angle could cause a pull to the left.
 
72bluNblu said:
Looks like you have .4° of cross camber and it would be set to pull left. Typically the max cross camber you want is .5°. It's in the correct direction to correct for road crown, but if you're driving on roads without much crown you might notice some pull to the left with that setting. You said it was only a slight pull, so, that could be part of it.

Also, it looks like you had them do the right thing and run positive caster, so I'm assuming you're running radials. But you also have positive camber? It's a small amount so it's not a big deal, but you'd be better off with slightly negative camber than slightly positive.

And if you turn your camera sideways and zoom in a bit it will be a lot easier to read that alignment sheet. :D
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yeah I told him to max the caster but he didn’t go half -.5 camber didn’t wanna bring it back because it was the second trip out there think it’s what causing my problem?
 
Gabriel Larson said:
yeah I told him to max the caster but he didn’t go half -.5 camber didn’t wanna bring it back because it was the second trip out there think it’s what causing my problem?
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I don't think the positive camber is what's causing your problem, but the cross camber at .4° might be. Like I said, that will have the car pulling left. The road crown will counteract that, but if the roads you're driving on don't have a heavy crown you may get some pull to the left. Normally .5° cross camber is the maximum allowed, and typical is more like .25°. It's a small difference, but if it's only a slight pull it could be part of the problem.
 
You can do "all that" and you may end up having to, but start with the tire cross first. It's free, quick and will eliminate or confirm the tires. On a crowned road, I'd doubt seriously that camber difference would cause a pull. you never know though, since each one is different.
 
I’m going to start an argument here but thrust angle can INDIRECTLY cause a pull with power steering. Do I think yours is bad? No. Do I think your cross camber is bad? No.
 
Bodyperson said:
I’m going to start an argument here but thrust angle can INDIRECTLY cause a pull with power steering. Do I think yours is bad? No. Do I think your cross camber is bad? No.
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Yeah it probably is just tire pull when I was balancing one was bent but I forgot what one
 
None of it is that bad by itself. But it’s only a “slight pull” too. It could be the tire that’s worn from the previous alignment, or the cross camber, or the thrust angle, or a combination of all of them and something else we haven’t thought of yet.
 
Bodyperson said:
SAI ain’t helping either.
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And it was better when the car had negative camber. So was the positive caster. Switch that over to -.5*’s camber and the other numbers will look better too.

But it could be a worn tire. Or some combination of all of the above. Change one thing at a time until you find it.
 
Oh ****. You are from Oregon. All bets are off. Logging trucks ruin the roads. Pull left here pull right there. Same in my state.
 
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