Re: Front end shimmy and shake problem

Posted by Mike Flanagan on October 25, 1997 at 21:18:34

In Reply to: Re: Front end shimmy and shake problem
posted by Bob Carabbio on October 25, 1997 at 13:10:07

I agree with all Bob said and will add only that the front end alignment is critical. Especially if there is to little toe in. The front wheels want to wander with no toe in and shimmy is almost inevitable. Also check the tire pressure, even 5 lbs differential from one side to the other can set up a shimmy.
However the root of the problem is slack in the system and generally speaking the only way to find the culprit is to throw the baby out with the bath water so to speak and disassemble the front end and put 'er back together to proper tolarences. Ain't I a ray of sunshine....
God Speed Under 50.
The Model A Fool.
: The root cause of shimmy is always alignment-related which causes the front end to be "servo-unstable".Looseness, of course, can affect the alignment. Number one thing to look at is front wheel bearing tightness.
: What's real common is wear on the spindle caused by inner race spinning that destroys your ability to get the play out since the inner race of the bearing is loose on the spindle. The outer bearing is the most common offender.
: Tires are a common cause since A's aren't used much, the tires tend to get hard without wearing out.This changes the geometry of the application of the weight to the road and cause shimmy and wandering.If the tires are 5 years old, it could be time to replace.
: Check the tightness of the axle to the radius rod.With a LARGE pipe wrench see if you can rotate the axle in the radius rods.If so the situation must be corrected since this destroys the castor setting stability.Looseness in the radius ball is a factor if it's really bad.I use a rubber ball always.
: Check the tightness of the fit between the steering arms and the spindles.If there's ANY motion at the joint it's too much.
: Tie rod ends can be a problem if there's free play.Egg shaped balls don't matter as long as they're tight (makes for lousey steering though).
: ALthough Shimmy is primarily affected by things that change the relationship of the wheels to each other, or to the chassis, you should also check the tightness of the pittman to the sector shaft.It loosens frequently.Any motion is too much. Looseness in the steering box can be a factor.
: King pins aren't generally involved unless they're REALLY bad.

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