avgwarhawk

Let's Talk Ball Joints

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Of my years as a mechanic (I worked primarily on vehicles from the late 70's through the 90's) and ball joint play assessment that had any real movement required replacement.  I find it interesting the allowable lateral movement of 1/4 or less on a unloaded lower ball joint on the 1959-1960(and probably others) astonishing.   Perhaps it is the position of the ball joint itself?  Sits in a cup holding the vehicle weight?   What is your experience with ball joints on your Buick?  Simply replaced because of mileage?  Noted some play when unloaded with a floor jack and replaced?   Had nothing better to do on any given Saturday? 

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2 minutes ago, Ben Bruce aka First Born said:

Can't answer your question, Chris. Sure wish there was an easy way to change my king pin to ball joints.

 

  Ben

 

King pins are a whole other ball of wax.  I have done a few on Ford I-beams.  Have a press will travel.  I was checking the 60's front end last night because she started to wander the road a bit more then I'm accustomed.  The lower ball joints have play.  The manual reads the unloaded lower ball joint will have play.  If over 1/4 inch lateral(circumference of the wheel) it is time to replace.  I just found it odd to have any play at all.         

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1 minute ago, old-tank said:

Order some new ones and if they are the same send them  back.

 

I do have a set on the way. If for anything, I have them handy if and when needed.  The ball joints have 35k service.  Certainly could be worn if left un-lubed.  But, these as well as the other suspension parts appeared to have been lubed over the years.  I lubed them twice.    The manual states the lower ball joints will have play when unloaded with a jack under the lower control arm.  Up to a 1/4 inch lateral play is normal.   I'll see how the new joints react while unloaded and sitting in the cup.  

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2 minutes ago, avgwarhawk said:

   The manual states the lower ball joints will have play when unloaded with a jack under the lower control arm.  Up to a 1/4 inch lateral play is normal.

Driving through dips will have the joints unloaded and with 1/4 inch play it will be steering itself for awhile.  If new ones are tighter this is one case that 1960 engineering can be improve upon.  Are you running bias-ply or radials?

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14 minutes ago, old-tank said:

Driving through dips will have the joints unloaded and with 1/4 inch play it will be steering itself for awhile.  If new ones are tighter this is one case that 1960 engineering can be improve upon.  Are you running bias-ply or radials?

 

There is some play when unloaded.  Enough for me to say...what the?  I did not make any measurements on lateral movement.  I will when I get a chance this weekend.  This lunatic runs  bias on both Buicks.   When I purchased the Buick it had a pull to the left.  I checked all parts, new tires,  no drum brake drag, re-packed bearings etc.  I then used the old string from rear to front and found the toe on the passenger side was toe in and creating a pull to the left.  Once I adjusted the toe via the string method the pull was gone.  Steering wheel straight. Easy no frills driving.   As of late she started pulling to the left slightly.  I'm a bit anal with alignments. I was an alignment tech for 2 years.  

 

1/4 is when the manual says to change out the ball joint.  I'll check again when I get a chance on actual movement.    

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Posted (edited)

As a side note,  mentioning dips in the road would unload the joint,  it may to some degree I would imagine.   Manual states full unload occurs when the lower control are is supported and tire off the ground.  

 

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Edited by avgwarhawk (see edit history)

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I am not a expert on this, but a 1/4 " lateral movement at the circumference of the tire sure seems like the joint itself would hardly seem loose?

Do I understand this right: The measurement at the tire would be 1/4 inch outward at any point on the tire, near the tire treads?

And if that is right, considering how far away the ball joint would be from the edge of the tire (at the center of the tire wheel assembly) I would think the actual ball joint play would be much less than a 1/4 ".  

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Posted (edited)
1 hour ago, JohnD1956 said:

I am not a expert on this, but a 1/4 " lateral movement at the circumference of the tire sure seems like the joint itself would hardly seem loose?

Do I understand this right: The measurement at the tire would be 1/4 inch outward at any point on the tire, near the tire treads?

And if that is right, considering how far away the ball joint would be from the edge of the tire (at the center of the tire wheel assembly) I would think the actual ball joint play would be much less than a 1/4 ".  

 

Lateral would be movement from front to back and back to front from my understanding.  In other words, the tire/wheel assembly would move backwards 1/4 of an inch.  When I unloaded the lower ball joint I could physically move the entire tire assembly from front to rear and vise-versa.  Was it a 1/4 inch in either direction?  I do not believe so.  I will attempt to measure.   Whatever the case, the manual said there will be noticeable looseness or shake.  There is!     

 

More reading and posts below reveal some interesting things on load bearing lower ball joints.  

Edited by avgwarhawk (see edit history)

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M-S01-9-1.jpgBall joint wear can be checked for both axial (vertical) and lateral (side-to-side) play. Image courtesy of Moog Steering and Suspension/Federal-Mogul Motorparts.

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Posted (edited)

 

Bearing the Load?

Ball joints can be broken down into load-bearing and non-load-bearing categories. A load-bearing ball joint is designed to support the weight of the vehicle while providing a hinge point for the steering system. Most load-bearing ball joints are designed to cancel the effects of normal wear by centering themselves in their own sockets. (interesting!!) 

Non-load-bearing ball joints, on the other hand, are designed to maintain precise dimensional tolerances in a steering or suspension system. Wear in a non-load-bearing ball joint will cause a noticeable change in the camber, caster or toe angle of a front suspension. Consequently, non-load-bearing joints are preloaded in order to compensate for wear. Unloaded control arm ball joints should be tested for preload when the suspension system is disassembled.

 

 

https://www.knowyourparts.com/technical-resources/suspension/measure-ball-joint-wear/

 

Edited by avgwarhawk (see edit history)

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I was able to check ball joint play again. The lower joints have very little play from 12 to 6 o'clock. Very little play 9 to 3 o'clock.  Certainly not a 1/4 inch!  No where close.  I did some more reading and found load bearing lower ball joints do wear faster than non-load bearing joints.  So, lubed the rest of the front end. Will keep rolling. The new joints I'll keep on hand.

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Just a note, another culprit for mimicking this kind of cascaded movement can be in an incorrectly tension set outer wheel bearing or even a sudden internal fated failing wheel bearing while still rendering no noise when checked with a quick outer jerk or spin of the tire.  If you cannot discern aberrant improper seated ball joint movement, then I would tear down that wheel's spindle components and remove, check and repack and make a point of properly torque seating of that outer wheel bearing once again.  As this has happened to me and found it worked out even though I had worked on that wheel/spindle just a couple months prior and assumed everything I had done was proper because I had done this operation many times before over the years.  Sometimes we get interrupted during the teardown / reassembly process and then all bets are off. 

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On 4/26/2019 at 12:31 PM, old-tank said:

Driving through dips will have the joints unloaded and with 1/4 inch play it will be steering itself for awhile.  If new ones are tighter this is one case that 1960 engineering can be improve upon.  Are you running bias-ply or radials?

 

 

Received the new joints today.  There is very very slight play in the new joint.   I'll keep these new joints on hand.     

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10 hours ago, Bill Stoneberg said:

How is your center link ?

have you looked at that ?

 

 

Hello Bill,

 

Yes sir, all related parts are in good knick.   Road crown and bias ply are not the friendliness.   I have noticed that bias ply and concrete highway like each other.  Any who,  I plan on rotating the tires and roll with it.   

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