Front end darts side to side - Ford Mustang Forum
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post #1 of 17 (permalink) Old 10-06-2019 Thread Starter
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Front end darts side to side

So I replaced my front radius rod rubber bushings , now when I get on the highway it feels like its all over the place slightly darting side to side ....very scary .... any input would be greatly appreciated .....thanks

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post #2 of 17 (permalink) Old 10-06-2019
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Sounds like alignment time.

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post #3 of 17 (permalink) Old 10-06-2019
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Did you get it aligned?

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post #4 of 17 (permalink) Old 10-07-2019
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Strut rods = Caster settings. You really need as much caster as you can probably get; 3 degrees or more for manual steering. With power steering, you'd want a degree or two more. It directly affects return-to-center, and high-speed stability. Too much will require more steering effort. Not enough (or negative!) will result in a car that wants to turn all the time, without any help from you. Instability that gets worse at high speed. Modern radial tires require a lot more than the old bias-ply ones for proper handling, which is why these numbers do not agree with the Ford shop manual.

You will also want to make sure you have about 1/8" of toe in (1/16 on each side, so the tires are being pushed back to '0' toe when you're rolling down the road ideally), and about .25 degrees of negative camber. Just avoid positive camber, and if you're actually driving on curvy roads or autocrossing, a little more would be fine. Having too much will result in uneven tire wear.

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post #5 of 17 (permalink) Old 10-07-2019 Thread Starter
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No , I have not had an alignment in a few years . I just thought it strange that this would occur so drastically after a simple replacement of rubber bushings on the radius rods .... Thanks for the input , I appreciate it . I will arrange an alignment and see how it improves .

Rick
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post #6 of 17 (permalink) Old 10-07-2019
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No , I have not had an alignment in a few years . I just thought it strange that this would occur so drastically after a simple replacement of rubber bushings on the radius rods .... Thanks for the input , I appreciate it . I will arrange an alignment and see how it improves .

Rick
I have just replaced the bushes on mine.
I found when I had removed them from the strut rod that under the bushes were corroded. I had to replace them.
Were yours corroded?

Absolutely, you need to get the front end aligned after changing the bushes.

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post #7 of 17 (permalink) Old 10-08-2019
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Strut rods = Caster settings. You really need as much caster as you can probably get; 3 degrees or more for manual steering. With power steering, you'd want a degree or two more. It directly affects return-to-center, and high-speed stability. Too much will require more steering effort. Not enough (or negative!) will result in a car that wants to turn all the time, without any help from you. Instability that gets worse at high speed. Modern radial tires require a lot more than the old bias-ply ones for proper handling, which is why these numbers do not agree with the Ford shop manual.

You will also want to make sure you have about 1/8" of toe in (1/16 on each side, so the tires are being pushed back to '0' toe when you're rolling down the road ideally), and about .25 degrees of negative camber. Just avoid positive camber, and if you're actually driving on curvy roads or autocrossing, a little more would be fine. Having too much will result in uneven tire wear.
All good info! Here's a bit more: Caster is responsible for keeping the car going in a straight line IF: the caster angle is EQUAL on both sides, so long as it is not negative caster, AND, Toe-In is what keeps the vehicle from darting from side to side, as described. If the caster angle is GREATER on the right side, for example, the weaker caster force on the left side will allow the Toe-In to drive the car to the LEFT side, and vice versa.

One can easily measure the toe-in using a steel tape measure. If the wheels are found to be TOWED-OUT, no matter the caster setting, it will wander from side to side. Correcting toe-in often makes the vehicle acceptable to handle. Check it. Toe can be changed by road hazards bending suspension parts, it don't take much!
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post #8 of 17 (permalink) Old 10-08-2019
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All good info! Here's a bit more: Caster is responsible for keeping the car going in a straight line IF: the caster angle is EQUAL on both sides, so long as it is not negative caster, AND, Toe-In is what keeps the vehicle from darting from side to side, as described. If the caster angle is GREATER on the right side, for example, the weaker caster force on the left side will allow the Toe-In to drive the car to the LEFT side, and vice versa.

One can easily measure the toe-in using a steel tape measure. If the wheels are found to be TOWED-OUT, no matter the caster setting, it will wander from side to side. Correcting toe-in often makes the vehicle acceptable to handle. Check it. Toe can be changed by road hazards bending suspension parts, it don't take much!
You need to study up on alignments.
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post #9 of 17 (permalink) Old 10-08-2019
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Toe problems can definitely make a car's handling 'darty' and weird too. But given that he was replacing his doughnuts, chances are, that's where this problem came in, so my money's on caster here. Ever push a shopping cart where the front wheel's gotten punked on a curb or pothole? The wild flopping and gyrating is because of negative caster, with the wheel bent backward. The wheel WANTS to turn, and self-steer to any direction but straight. With toe problems, the car's tires scrub and squeak a lot, even at low speed cornering, and you get very rapid tire wear. In my experience, toe-in tends to make your car want to pick a direction to turn, and stay with it. Toe out makes your car mostly eager to go 'straight(ish)', but in a very vague, wandery way. In either case, with extreme toe problems, you'd notice as soon as you started rolling. Caster problems are often less noticeable at low speeds, but progress to something quite frightening as you accelerate.

As I'm writing this, it occurs to me that I've driven a lot of cars with improper alignment over the years, in order to become familiar with 'what's wrong with this thing?'. *laugh* One thing I can say with great certainty: When you know that there's something wrong with your car's handling, regardless of the symptoms, check your parts first. If you already know they're fine, or they're fixed to be that way, THEN deal with alignment, and get everything right when you do it. One adjustment often affects another, so just get it right, and then enjoy.

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Many of the big cars ran negative caster so the blue haired ladies can steer easily. To get a shimmy you have to be way out on caster. Yes toe can cause that darty feeling and too much can cause the car to drive like a John Deere tractor, but caster will not. Most cars on the road use a toe in adjustment, however performance track cars can us toe out settings.

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I have never pushed a car with caster issues hard enough to find out what happens when you ignore the stability problem and just keep going for speed. After doing some work on my car when I was about 16, I went out and romped on it, and pretty much had a brown trousers moment as I discovered some important truths about alignment. (caster being one of the important things I learned about that day) It did *feel* like my car wanted to just dig in and swerve to the side (either side) with no provocation. Not a confidence-inspiring feeling!


I can also say for certain that bias-ply tires, for whatever reason, don't mind a lack of caster nearly as much as radials do.

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You need to study up on alignments.
Will you explain why? Maybe you did not understand. Or maybe you know lots more than I do.

BTW, sure wheels are frequently toed out, in fact, virtually every front wheel drive uses toe out. Do you know why? Tell us if you do, please.

Hopefully, both of your posts are addressed
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Will you explain why? Maybe you did not understand. Or maybe you know lots more than I do.

BTW, sure wheels are frequently toed out, in fact, virtually every front wheel drive uses toe out. Do you know why? Tell us if you do, please.


Hopefully, both of your posts are addressed
.
Yes, I do know why, but we aren't talking about FWD or 4wd drive vehicles in this discussion... Why even bring this up?

We also don't need to get into a conversation about the Ackerman effect.
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Many of the big cars ran negative caster so the blue haired ladies can steer easily...
The easiest to steer safely without power steering is with zero caster which is why a great number of older cars were built that way. My grandmother would not have known what the word 'handling' was supposed to mean but she could recognize an easy-turning steering wheel.
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Yes, I do know why, but we aren't talking about FWD or 4wd drive vehicles in this discussion... Why even bring this up?

We also don't need to get into a conversation about the Ackerman effect.
Why bring it up? Because it explains that toe-in is not always specified. And, you mentioned toe-out, but little else about it.

What does the Ackerman Principal have to do with any of this, anyhow?

Do you always get pissed off when someone asks you about your veracity?

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