After removing the engine / trans on my 26 I noticed the ball bearing in the 4th main had moved rearward, enough that it had been contacting the U joint on the driveshaft.
Not a huge amount of damage done although the ball bearing will have to be replaced. I believe when I installed it I followed all the instructions...any one else had an issue with these units

Dave Eddie

Just pulled the engine in my 26, the ball bearing 4th had self destructed, the caller was loose on the shaft, the bearings escaped and some of them ground to pieces and distributed throughout the engine.

I think this is why rebuilders use the original ball cap. Added complexity is sometimes counterproductive. I have one of those ball bearings that turned up in some auction stuff. I won't be using it.

So if one was to revert back to the babbitted ball cap, what should I be looking for, I take it the Babbitt is a wear item?

Not too much of an issue with the babbitt being a wear item so long as everything in the trans is set up right and your pan is straight. Babbitt fourth mains will always leak a little no matter how good everything is set up. Most of what people have been trying to do with a “modern” fourth main is to seal it up. Some people have these modern ball bearing fourth mains and claim to have no trouble, however, I have seen too many of them failed in one form or other to think that they are a good idea. The modern setup requires you to bond the bearing to the shaft. If there is ANY wear on the 3rd main thrust the output shaft pulls back a little every time the car is in low, reverse, or neutral. This causes the ball bearing to take up the thrust which causes it to fail. The modern ball bearing is designed for radial load and can not tolerate thrust load.

Yes. It's just like the engine block. New Babbitt is poured and bored. Check the books for proper clearance.

I run two ball bearing 4th mains and they work fine. I did replace the bearing on one. It was a poor quality Asian unit. Replaced it with a better quality SKF.

Its been many years since my 40 hour class on bearings,but i would dissagree at a ball bearing not handling thrust! The right bearing would be a double row angular contact? Such bearing must also be sealed to keep clean lube in and dirty oil out.I think most problems are from using the wrong bearing and going CHEAP!! Another problem i think is when the 3 babbitt bearings wear in the ball does not?I found a poor quality unsealed shot bearing when i busted a crankshaft?? Bud.

The ball caps that are called for to be Glued to the tail shaft, there has been a lot of trouble with them. It is not a sound principle.

You just can't have a bearing insert stuck to a shaft, and the end pressed in to the bearing that is 5/8's wide. It would be the same if the clearance is wrong on just bearing, to shaft.

A Babbitt ball cap should be NOT under .002-50 thousandths minimum, and NOT over .003 Maximum, clearance to shaft.

Just heat expansion, back and forth, will take out the bearing, as there is no place to expand to, or come back to.

We started making Ball Bearing Ball Caps in the early 1970's. We have never had a bad one.

The size of bearing we use, you have to cut the tail shaft .050 under,( and you don't have to cut your drive shaft tub Bell) with about .000-50 thousandths clearance, for the bearing. Normally the tail shafts are not true anyway, and have taper.

The second choice is a bearing that is close to shaft size, so you don't have to machine it. The reason they are not the best is, you can't get the required .000-50 thousandths to fit the I.D. of the bearing, and also have to cut the drive shaft tub Bell.

The third is the one with the insert that is glued to the tail shaft, and is doomed from the start, and you have to take even more off the drive shaft Bell.

There are also ones that are made out of Aluminum castings. I have experience with 3, in about 5 years, and all had the bearings set cocked,they were also Brand New, and and where the flange, run on a mandrel, inside the bearing, was a 1/4 inch out.

We make our ball caps out of good Ford, ball cap cores. The last few years, we only sell to certain engine builders, and they buy all we have time to make.

One last thing, the bearings we use now, are Japan made, and use dust covers. they cost me 40.00 each, the last batch we made. If a sealed bearing is used, they are 100.00 my cost.

Herm.

Pictures: The Babbitt Ball Cap one, is spun poured.

Dave,

Les Schubert has had good luck with the ball bearing 4th main. Give a call. He is a fellow Canadian.

Has anyone tried using a roller bearing?

The ball bearing and roller bearing fourth mains are a sure crank buster!

Why wouldn't some type of a bronze bushing pressed in the ball cap and machined to size work in place of the old poured babbitt? After all, the drive shaft spins in a bronze bushing inside the drive shaft tube immediately rearward of the universal joint. Like Steve said above, "complexity is sometimes counterproductive". We are also using bronze/brass thrust washers in our rear axles now instead of the lousy original babbitt washers.

Mike, I asked that a while back and was told it would gall. I actually made one and bored it to size but didn't install it. It sure fit real nice and I could do it in my shop. Maybe someone could explain the galling problem.

I'll go along with Kenneth DeLong. GM used ball bearings on their front wheels for decades - at least well into the '50s. If a ball bearing couldn't take thrust loads this wouldn't have worked. GM had no more problems with front wheel bearings then the companies that used rollers.

A brass bushing in the drive shaft tube, will work because there is not all the cast filings in that bushing, just gun grease, with low dirt. When you grease the bushing, it normally will push much of the dirt out of the bushing, if any.

In the ball cap there is always dirt going through the bushing and can't embed its self in harder brass, as in softer Babbitt, so the dirt just tears up the brass faster.

Also, the bigger the clearance the ball cap has, the harder it is on the crank shaft from the tail shaft jumping around, in a ball cap. It will flex the rear flange, and through the mains out of alignment, also cause faster in line wear.

Needle bearings, or any bearing that runs direct on the shaft will fail, as the shaft has to be as hard as the bearing, and it is not. The ones we have pulled down were chewed up. Maybe workable with a harden collar, pressed on the tail shaft?



Herm.

Norm is correct and also another factor is the trash generated by bands fouling roller or needle bearings. My experience was a roller bearing wearing into the shaft which ultimately got two cranks. I should have caught it after the first one but very carefully checked every possibility after the second one.

Roller bearings;
A modern roller bearing could work just fine IF you installed a case hardened inner race AND the bearing had at least a seal on the engine end. Otherwise it will wear the shaft fairly quickly.
Ball bearing;
I have installed a number of them with ZERO problems!!
Here are MY rules for this application
1. The installation MUST freely accept end floating. NO thrust loading on the bearing
2. I prefer to lock the bearing to the shaft, but then the outside MUST be freely floating to accommodate rule ONE!!!
3. I buy ONLY quality name brand bearings (SKF or similar)
4. I ALWAYS verify that the output shaft has minimal radial “run out” with a dial indicator prior AND install the ball cap with the engine standing vertically nose down AND then pin it in place so no artificial loads are being imposed on the rotating parts.
These are MY rules. So far no problems in 45 years and many thousands of miles!!
Further, of course, I have developed my floating transmission shaft and that has also been 100% satisfactory