alignment, shake and wobble question

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Old Aug 10, 2018 | 07:27 AM
  #1  
Minnesotajeff's Avatar
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From: 56425
alignment, shake and wobble question

Last winter I replaced every component in the front end of my '72. All bushings, ball joints, tie rod ends. I aligned it myself using a set of turn plates and a Fastrax alignment tool. I love diving in to new learning opportunities like this and buying the tools so i can handle these types of things in my own shop.

I have checked and tweaked the alignment several times this summer, trying different camber/caster settings to learn how it changes the handling and feel of the car.

The one thing I can't seem to tune out of it is a very slight wobble or shake that happens between 30-40 mph. Nothing seems to affect it. I can't make it worse or better. I've tried rotating the tires and nothing changes.

Looking for ideas on what to chase on this one...... i'm running 1/8 inch toe in. Maybe play with that setting? after 40 mph it is smooth and straight with no issues

Thanks
Old Aug 10, 2018 | 07:43 AM
  #2  
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Does it keep getting worse as you speed up?
Old Aug 10, 2018 | 07:53 AM
  #3  
Minnesotajeff's Avatar
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No, its just between 30-40mph and very slight the entire time. it wobbles the same at 40mph as it does at 30mph

it's mostly annoying more than anything

Old Aug 10, 2018 | 08:58 AM
  #4  
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Bent axle, bent wheel, bad tire, ujoint, motor mount, wheel bearing play, just guessing.
Old Aug 10, 2018 | 12:58 PM
  #5  
69 Ragtop's Avatar
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From: Lebanon, Ohio
Do you have any play in the steering wheel? If any at all, these "A" bodies like to go unstable at their resonant frequency, which for you appears to be between 30 and 40 MPH. Steering boxes spend 90% of their running lives going straight ahead, and that's where they like to loosen up. Consider tightening up the steering box. An adjustment may help, but you may require a box rebuild. (...or it might be one of the problems oldcutlass mentioned, and add unbalanced tire and bad shock(s) to that list.)
Old Aug 10, 2018 | 01:54 PM
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OLDSter Ralph's Avatar
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1. I would start by borrowing a pair of good tires/wheels. Replace the front tires and check. If no change, replace tires on the rear and check.
2. If no change, then get it on a rack that allows running the car. With an observer below, run to 30-40 mph and watch wheels for wobble or other unusual things.
3. If this doesn't show up anything, start looking at the drive train. Start at the transmission.
Old Aug 10, 2018 | 02:06 PM
  #7  
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From: Edmonton, AB. And "I am Can 'eh' jun - eh"
The question I would ask is 'Did the car drive normally before you did all this work"? If it did, the problem is with something you've done, not the wheels, tires, rear axle etc.
Old Aug 10, 2018 | 03:04 PM
  #8  
OLDSter Ralph's Avatar
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Originally Posted by Allan R
The question I would ask is 'Did the car drive normally before you did all this work"? If it did, the problem is with something you've done, not the wheels, tires, rear axle etc.
Allan, that's a very good point. I never gave that a thought. We have some really smart people on here.
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