Ball Bearing Size and Type

Thanks EL for this great information. I actually did notice the joints material was very hard. I tried using a center punch to mark the way it came apart. Lost the point on my punch. So I used a cutoff grinding wheel to make a very small line. I did try to keep the bearings organized but lost that. My concern is the very slight rust found on part of the balls. They are clean now but I'm suspect about them. Wish I had know what you posted before I removed these for cleaning but its a steep learning curve.

Hello, Ball sizes were custom matched at the factory to fit the joint. They had several sizes to select from. Since they were much harder then the joint , I don't believe that yours are worn. I would also hesitate to dismantle unless you marked them and put them back in the same pocket. In most cases all the wear is in the pocket and not the ball. Also, most joint noise is from the outer because of the sharper angle for which they run.

I can't speak for 810/12 Cord but L-29 Cord inner housings have two balls that move back and forth in a housing and the housing is 62 Rockwell, which is pretty hard. I have tried making the balls less Rockwell too save the housing wearing but it didn't work. The balls wore out very fast against the harder housing. I would guess the 810/12 would also have hardened parts. I would think the hardness should match. Most machine shops can check hardness for you while you wait. I think the balls at McMaster Carr will have the hardness listed. Just my opinion on a car I know little about!
Cordially Mike

Thanks Mike.. Both Mcmaster Carr and Grainger are bout 2 miles from me. The advice I asked for is what material should I use. I found chrome precission. Carbon steel and something called monkey fist ball bearings. Mine are just under 1.000. The 4 I measured were 0.998 to 0.999 in size. I figure I need the carbon steel ones because the chrome ones may wear out the dog bones areas of the joints. Just wondering.

McMaster Carr sells all kinds of round ball bearings. Their descriptions are very complete. I didn't check your size specifically
Cordially Mike.

So I have both of my inner universal joints apart and measured one set of balls. they are .998 to .999 size so I'm thinking they are worn from 1.000. Looking on ebay there is thousands of suppliers selling precission chromed 1 inch balls. Then there is steel core monkey fist balls??? Then I found a steel ball bearing with a warning it will rust. The steel bearings I removed had a small bit of rust on them where the last 35 years attacked them sitting up high on a shelf. So what has been found to be workable when replacing these. I'm concerned the chromed precission balls will wear the dog bone side of the joints faster. What is the collective thoughts and whats a monkey fist, Steel core balls. I'm really confused now...