Measuring Pivot Center of a Ball Joint

[BBShark]

I'm looking for an easy way to measure the pivot center (ball) of a ball joint. Kind of hard to do with the methods that I can find. Most of them describe a process where you move the stem of the joint from one extreme angle to the other side and then find where the angles cross on the housing. Maybe OK if you have laser fixturing.

On most ball joints you can see where the ball intersects the stem but you don't cnow the diameter of the ball. Does anyone know if all the balls (used in ball joints) are some specific diameter?

There must be some easy way to do this. You see all these suspension computer programs with upper and lower ball joint centers located to 3 decimal places.

 

[ausbrian]

Hi, there is no easy way to calculate the ball joint center,unless you have the original cad file or drawing.What I do is move the ball joint stud from one side to the other and draw a line along the axis of the stud on the control arm.Do this again at 90* and you will have a pretty good idea of where the center is.As for suspension analyzer programs with 3 decimal points, this is a calculated number given from previous inputs.I used one for designing my suspension set up. What particular info do you need, I have late C4 front,C5,C6,front and rear data.

 

[BBShark]

I am using the so called "tall" truck ball joint (K6136) for the upper control arm joint on a C3. It's been a while but, looking at the stock joint and the truck joint makes me think the difference is maybe 1/4". That hardley seems worthwhile.

I have never found any drawings that identify the pivot centers for different ball joints.

 

[ausbrian]

Sorry don't have any info on C3 suspension,unless you know someone with access to GM drawings, best way is to use the method described above for getting ball joint center location.This method will get you within 1-2mm if you have a good eye.This is more than enough accuracy for doing your suspension calculations.

 

[mfain]

Try this.

 

[voodoovette]

More info on this upright please, is this for a C-3 ??. Who is the MFG and cost?

 

[mfain]

More info on this upright please, is this for a C-3 ??. Who is the MFG and cost?

It is an ATS/AFX spindle, now sold by Speedtech in St. George Utah. It is actually made for a Camaro (note that the lower ball joint comes in from the bottom, unlike the C-3; however, I have used the ATS spindle with a C-3 control arm by welding a screw-in ball joint sleeve into the control arm and re-orienting the stud to point up. My C-1 Corvette has a now much modified C-3 front crossmember and at one time I had pretty much stock C-3 suspension with Herb Adams VSE ny-liner control arm bushings and coil-overs. Then, I later switched to late C-4 control arms, and more recently fabricated tubular lowers (I moved the inner pivots inboard for longer lower control arms for geometry considerations). The spindles use C6 bearings and will take any C6 brake set-up. I think the newest Speedtech spindles are 7075 aluminum and come with ZR1 bearings -- they are a little over $1000 a pair, I think.

Pappy

 

[voodoovette]

Great info, I will check it out, thank you!!