• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Mini Hub Failure

Share this page

aeronca65t

aeronca65t

Great Pumpkin
Offline
I was two cars behind Tom Chisholm in his Mini-Cooper at the Pittsburgh Vintage last Saturday when his hub failed. The car in front of me is an MGA and the car closest to Tom is an Elva Courier. Interestingly, another driver (Jim A.) had left his Mini home this year because he was having doubts about one of his front hubs. Anyway, here's the video:
 
There is a thread at Mini Mania which I presume concerns the same car. From the photos posted there it apears that the right front hub came apart with the CV joint nut coming off and releasing the bearing. Again, if it's the same car, the body is distorted and the team is looking for a shell to replace it.

EDIT: New photos at Mini Mania (7/24/13) show the car to be #8 and the right front hub definitely came apart. The photographer went on to say that the driver credits the cage for protecting him. The shell is definitely twisted beyond use.
 
Last edited:
Yep......and I think the cage was an FIA aluminum cage (the car is an ex-rally car). Anyway, one of the other Mini drivers (Mack M.) made this comment on our VRG e-mail list and others seemed to agree, including the owner (Tom C.)-----------> Both Mini front hubs (really part of the outboard CV joint) have right hand threads onto which the "big nut" is threaded (see diagram at link Ian posted). Rotational forces on the RF tend to tighten that nut. But on the LF tend to loosen it. That nut goes on with 150 lbs.ft of torque but if the spacer in the tapered bearing assembly gets pounded down the whole assembly can loosen. I have also had the conical washer (aka tapered collar) break into several pieces. There are hardened versions of both the conical washer and the bearing spacer (EN40B material) available because of these issues. I have switched to both. I torque mine to 150 lbs/ft and just a little more with the cotter pin biased in the castellated big nut such that I know, by visual check, if that big nut has backed off by even less than a mm. I check that after EVERY session. I have seen that cotter pin partially sheared by the big nut beginning to back off. It is always on the LF.

I would suggest that Tom's bearing assembly loosened, the LF big nut started backing off and sheared through the cotter pin. After that it was just a matter of time before nut spun off and the LF drive flange and attached wheel came off. The failure in the brake rotor was secondary as the disc portion was held in the caliper. This is the common area for these rotors to fail, and I suppose it is possible that the rotor failed under braking and that preceded the events mentioned above.

The important thing is that Tom is OK. As many have remarked...it could have been much worse.

Mack
ieANcC1.jpg
 
Back
Top