2-27-07 - Finding control arm ball joint pivot points

In order to use the new Performance Trends software I needed to know the exact pivot points of the ball joints for the upper and lower control arms. I've heard of people actually sawing a ball joint in half to find the point and thought this might be an effective way to do the same thing. I took two photos with the ball in different positions, overlaid them in PhotoShop and drew the center lines. The crossing poing is the pivot.

3-3-07 - Ball joint pivot point redux

The more I looked at the first attempt at finding the pivot points, the more I realized I needed to figure out a new way to determine the center line position. After taking more photos (with white backgrounds) and very carefully determining the center line positions, I have revised the pivot points. The process:

Took three photos with the ball in left, center & right positions. Overlaid the photos in PhotoShop for position. Edited the photos so you could see all three shaft positions clearly. Drew "blocks" over the top of the threads (in PhotoShop) and compared edges of blocks to major and minor diameters of threads. Cut the blocks in half (calculated the number of pixels) to find the actual center of the shaft. Drew center lines based on the 1/2 block. I feel pretty good about these now.

3-8-07 - Spherical Bearings

After a bunch of screwing around with the "rubber" lower control arm bushings, I decided there had to be a better way. There is, speherical bearings. This has been done lots of times before but all the ones I've seen don't have bearings that allow lubrication. Since this is mostly a street car I felt that greasable bearings was a must. Not only that but just in case the spherical bearings were too harsh (ride/road noise wise) I can always go back to the rubber versions.

I found the bearings on McMaster-Carr's web site and machined the adapters out of aluminum. The seals are buna-N cups, designed for hydraulic cylinders. I'm very close to assembling the first set.

3-20-07 - LCA Spherical bearings - progress

Made more progress on the LCA bearings. I've turned steel inner bushings out of some 1018 1" O.D. .250" wall DOM steel tube. The bushings are split into two pieces because they need to provide a seat for the spherical bearing ball to maintain position of the LCA when mounted.

Since the frame "ears" aren't consistent in terms of width (they're welded this way), I have to custom fit each of these. Here's a photo of the bearing insert in the LCA tube and a picture of the inner bushings in progress.

Another mod: The LCAs had press in grease zerks so I welded the holes shut, drilled and tapped for 1/4-28 zerks.

A few more photos in the Front Suspension Gallery.