Well....

THIS isn't good....

Bad Box

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Smoke makes things work. When the smoke gets out, it stops!

Name Change, Box of Gears!

Yes, that's rather apt!  

I really don't know what has happened here.
I've pulled lots of classic mini engine/box things to bits and rebuilt them in my time, and I have NEVER seen a box destroy its double-row bearing like this.

I've seen plenty of bad bearings, worn bearings, loose or tight bearings, but I have never seen one of these so badly destroyed that it has dropped its balls - literally.

There are about five balls from the bearing, gently soaking in oil in the bottom of the gearbox.

I'd love to know if anyone has a theory as to how this could have happened.
The only thing I can think of, is that the bearing was a factory dud from the day they put it in.

Have had a similar thing happen on an old ZA Fairlane rear wheel bearing. The riveted cage that keeps the balls evenly spaced came apart. When all the balls move to one side the gap between the races opens up enough for the balls to fall out.
The reverse of that is how they put them together.

It made things quite interesting. Without the balls the brake drum and shoes became the bearing and quickly got red hot. The heat then melted the wheel cylinder rubber cups, letting out all the brake fluid. With a single master cylinder that meant no brakes.
The bearings not only hold the car up they keep the axle in. The low mudguard stopped the wheel escaping altogether but now there was no handbrake either, nor engine braking as the spline end had disengaged from the diff.

Fortunately it was a flat road so coasted till it stopped.

Yes, that must have been what happened here.  I don't see how else the balls could drop - out of the bearing, that is.    

Your example is rather scary!

All the usual backups you'd use to stop the vehicle are GONE!
Yikes.....

If on a hill, that could have ended very badly.

I have seen bearings do similar too. The cages can fracture over time and crack. Then they disintegrate and the balls fall out like Phil's experience.
I have seen the same with tapered roller wheel bearings too, cage disintegrates rollers fall out, wheel wobbles badly.
That gearbox must have been making some amazing music when that bearing died.
Pete

  Godoh said  

That gearbox must have been making some amazing music when that bearing died.
Pete

Yeah, I mean - this is BAD.    

But then, some people will just keep on driving till it craps out completely, totally IGNORING any really nasty sounds!  

G'day,
Now that is what could be called a catastophic failure  

This was bearing was not unknown to give trouble but that is the first I have seen completely fail. There is a fair chance the cage failed and the bearing let go of the balls all at once, one loud bang with no warning. Very noisy afterwards  

I seem to remember there are 4 different cage styles for these, riveted steel, pressed steel, bronze and nylon. Advise at the time was NOT to use the nylon ones EVER, the riveted are OK but the rivets can fail (I think thats the style that failed in Grogsters video), the bronze are pretty solid (not always, as below) and the one piece (per row) pressed metal type where the ones to use if possible.

Many moons ago (30+ years) the one shown was replaced during a rebuild, it showed no signs of distress and if I hadn't noticed the balls moving around during cleaning it would have gone back in, maybe only to fail at some point.





At this time I was driving a 1963 Mini 850 (1098 power), my sis had a 1965 Mini "K" 1100, Mum had a 1978 Clubman LS 1000, plus a few mates had them as well as a few out in the paddock, they were great fun but not really well suited to country Victoria, I was doing 600km per week and it took its toll on the old girl.

Just happy that I still have her after 35 years and have started aquiring parts for a ground up rebuild.

Regards, Lyle.
Edited 2026-08-24 23:54 by mozzie