Radius Ball Question

[Tony G]

The radius ball on my 1929 AA has some wear and it came with the rubber ball over it. What is the best way short of replacing the ball to repair this? I can reassmble with another rubber cover or use a hemi shaped steel shim washer. Ive heard the the rubber covers cause problems.
Thanks for any suggestions you may offer.

TG

[Tom Wesenberg]

One of my A's also came with a rubber cover and the original steel ball showed some wear. I removed the rubber and installed a new steel kit and it fits and works well. Measure the wear. It may not be as bad as it looks. The ball should be 1 1/2"

[Purdy Swoft]

Not for the sake of disagreement but I have used the rubber radius ball set up on every model A that I have ever owned. The only problem is that the rubber ball cover seems to be made of low quality live rubber and has to be replaced every so many years, more often If the A is a real oil leaker. Ford no doubt thought that the rubber radius ball cover was a better idea, because they used it from 1932 through 1948. The thing about the rubber ball cover causing front end shimmy is a myth. Impropper toe in adjustment sets up shimmy. Anything else that is loose in the front end or steering only adds to the shimmy after it starts. Just my opinion and experience.

[Tom Wesenberg]

You can buy a cupped washer to take up wear, if it is needed. Be sure to grease the ball and pocket well.

I was following a fellow cub member's car yesterday when I noticed his right front wheel started a bad shimmy, but the left front remained straight ahead. I hadn't seen this before, as the front wheels most always seem to shimmy back and forth together. With only the right front wheel going nuts, I'd suspect a loose tie rod bearing. It could be either side or both. He'll check it out this week and let me know.

[Louis]

Tony,
Yes the rubber radius ball can cause all kind of problems, encluding frt. end shimmy.

If your org. ball is not damaged to much,Throw the replacement rubber ball and cap away.

Order the authentic radius ball kit A-3440-s from Snyder's.

You'll be a happy guy.

[RockHillWill]

Sponsored Links (Register now to hide all advertisements)

If you consider that the distance from one king pin to another across the front axle is roughly the same distance as from each kingpin to the wishbone pivot, they form an approximately equal angle triangle. In my opinion, that means if you have only .030" of play around the circumference of that ball that can move it will alternately give each wheel 1/16" toe in / out as it cycles from left to right.

I have only addressed a bad front end shimmy on two occasions, but each time it took reworking the wish bone ball to 1-1/2" diameter, and using original clamp halves.Then I re-bored both mounting holes in the base of the bell housing and installing a hardened sleeve in each of the bores for the wishbone mounting bolts. It was not kingpin wear, bearings, toe in/out or tires that created either of these shimmy's.

Even if you rebuild or replace the wishbone, another issue is almost always present, and that is those bores for the wishbone mount are wallowed out and worn in a manner that allows side movement as well as the fact that every bell housing that I have ever looked at has the counter bores at the top worn in a manner that lowers the mounting bolts 1/16" to 3/16".

In my humble opinion, no matter what you do to shortcut a correct wishbone repair, it does not address this issue.

Just a thought!

[Tony G]

As it works out I took Tom's advice and measured the ball. It had very little wear so I assembled it like Henry would have wanted and it seems tight.I dont know what the previous guy was thinking. Aside from the felt pad above it I dont see that it can be lubed periodically.Thanks to all who offered advice.
TG

[Purdy Swoft]

Originally Posted by RockHillWill

If you consider that the distance from one king pin to another across the front axle is roughly the same distance as from each kingpin to the wishbone pivot, they form an approximately equal angle triangle. In my opinion, that means if you have only .030" of play around the circumference of that ball that can move it will alternately give each wheel 1/16" toe in / out as it cycles from left to right.

I have only addressed a bad front end shimmy on two occasions, but each time it took reworking the wish bone ball to 1-1/2" diameter, and using original clamp halves.Then I re-bored both mounting holes in the base of the bell housing and installing a hardened sleeve in each of the bores for the wishbone mounting bolts. It was not kingpin wear, bearings, toe in/out or tires that created either of these shimmy's.

Even if you rebuild or replace the wishbone, another issue is almost always present, and that is those bores for the wishbone mount are wallowed out and worn in a manner that allows side movement as well as the fact that every bell housing that I have ever looked at has the counter bores at the top worn in a manner that lowers the mounting bolts 1/16" to 3/16".

In my humble opinion, no matter what you do to shortcut a correct wishbone repair, it does not address this issue.

Just a thought!

Will,

Not to be disrespectful are try to discredit you. I beg to differ. If the radius ball is worn .030 that would equal just less than 1/32 .I set my toe in at 1/16 plus or minus 1/32. That would still be in range. Even if the toe in is set at 1/8 plus or minus 1/16 that still wouldn't cause shimmy. All of the worn radius balls that I.ve seen have been worn more on the bottom than the sides. That is the clearance that the cupped washer that so many seem to think is the end all fix all for a worn radius ball is suppose to correct. Metal to metal contact is what wears the radius ball over time. The replacement rubber ball is thick enough to take up all of the slack unless the radius ball is worn completely out to the point that replacement would be eminant. If the radius ball is worn that badly the cupped washer isn't going to remove all of the slack either. Ford must have thought that the rubber ball was a better idea than the flimsey spring and metal to metal radius rod set up that was used on the model A or he wouldn't have used it for the next sixteen years untill the radius rod front ends were discontinued. I don't have the green bible handy but I believe that the rubber radius ball set up was sold by Ford parts departments as a replacement for model A's with a worn radius ball. Ford parts sold lots of things for replacement on the model A that is not acceptable for points cars, but will work good. Just to name a few, they offered replacement spring shackles with rubber bushings, Marvel and then Tillotson carburetors and the list goes on.

Worn king pins are claimed to be the number one cause of front end shimmy. I have seen and owned a few model A's with badly worn king pins and bushings that did not have front end shimmy. Toe in keeps the wheels going straight. Anything that effects toe in will set up shimmy. Any loose parts in the front end or steering will greatly increase shimmy once it is set up or started. Just my humble findings after most of my life owning and repairing my model A's.

[Purdy Swoft]

Originally Posted by Louis

Tony,
Yes the rubber radius ball can cause all kind of problems, encluding frt. end shimmy.

If your org. ball is not damaged to much,Throw the replacement rubber ball and cap away.

Order the authentic radius ball kit A-3440-s from Snyder's.

You'll be a happy guy.

Louis,

You've really learned a lot about model A's in a relatively short time. Thats great, as long as it works for you.

[RockHillWill]

Good morning Purdy

No problem with me, I appreciate the reply and enjoy the conversation.

My statement was meant to say that if the radius ball has .030" play around the circumference, by moving in each direction it will result in 1/16" of play from one side to the other, which rotates the 'triangle', giving one front wheel the same movement resulting 1/16" toe out. The big issue to me in that regard is that while the toe-in settings that you make at the front wheels is a constant number. The radius ball movement is not constant, and I am of the opinion that this erratic movement of the radius ball can create a harmonic situation that reveals itself at the steering wheel.

Another issue to think about is if the radius ball is able to move from side to side and you apply the brakes, and both front brake shoes are not adjusted EXACTLY the same, you will pre-set the toe-out in the direction of the more tightly set front wheel.

The two occurrences that were referred to were my last two restorations and I knew that the front end parts had been restored pretty well, and the resulting front end 'issues' on both cars were corrected by dealing with the two areas that I presented.

I do mean to say that every front end issue is caused by those two areas, only that they deserve some attention if a problem persists.

I am also found that a nicely adjusted steering box is essential to this issue as well.

(I am leaving in 5-minutes for a week long metal shaping event, but will look forward to any input when I return)

[Barry B./ Ma.]

Originally Posted by Tom Wesenberg

You can buy a cupped washer to take up wear, if it is needed. Be sure to grease the ball and pocket well.

I was following a fellow cub member's car yesterday when I noticed his right front wheel started a bad shimmy, but the left front remained straight ahead. I hadn't seen this before, as the front wheels most always seem to shimmy back and forth together. With only the right front wheel going nuts, I'd suspect a loose tie rod bearing. It could be either side or both. He'll check it out this week and let me know.

Tom, tell your friend to check the steering arm on the right side. I had one that had a worn shank and allowed the right front wheel to shimmy. The big nut was tight and cotter pinned on mine but the shaft was worn behind the nut.

[Larry Seemann]

The radius rod ball is all about "caster". The only adjustment you can make in a Model A front end is "toe-in". "Caster" and "Camber" are set at the factory. The more the ball wears or the more the replacement rubber ball crushes the less caster you have and the less caster you have the more likely you are to have shimmy. As the ball goes up into the bell housing the caster diminishes. Did you ever wonder why the forks on a bicycle put the wheel way out in front of the handle bars? That's caster! If the wheel were directly below the handle bars the wheel would be whipping back and forth continuously and you wouldn't be able to control it at all. Makes you wonder how many thousands of hours were spent trying to figure that one out.
There may be other causes, but diminishing caster due to radius rod ball size reduction is the primary reason for shimmy in a Model A.

[Bob C]

I don't really see how the ball moving from side to side is going to change the toe.
The toe is set with the tie rod and your not changing that with movement of the ball.
I can see movement of the ball side to side causing the car to dog track. What am
I missing???

[eystein]

I built up mine with weld and filed it by hand to match the caps, using blue dye.

[Ross/Kzoo]

I also filled mine with weld and then checked it with a template. One with a 1 1/2" hole in the center of a 2 1/2""x6" piece of plywood and then with the hole at the edge. That way I could check every part of the ball and weld and grind til it was round.

[Louis]

Purdy Swoft,
Thank you for the kind words.
Yes some of us do learn quicker then other's.
If you ever need any advice, Please feel free to contact me.