Does anyone have a cross section view or exploded view of the wheel bearing and hub assembly? I am trying to learn about the parts and failure modes. What is anyone's experience with LF axle bolt loosening? My cotter pin has sheared for the second time.

xvracer wrote:Does anyone have a cross section view or exploded view of the wheel bearing and hub assembly? I am trying to learn about the parts and failure modes. What is anyone's experience with LF axle bolt loosening? My cotter pin has sheared for the second time.

I never found a diagram of our uprights showing all the bits exploded. For that reason, the first couple of times I took a corner apart, I kept the corresponding corner together so I had a model to copy. Having had more than a typical number of bearing issues in my last two years, a few tips:

(1) Find/buy/install the ball bearings that Enterprises (I think) had made up. It's lower friction, but more importantly I'm told that ball bearings go South in a more civilized manner. They get noisy and grunchy before they fail but will function for a while. Roller bearings go catastrophically presumably because the little cylinder-shaped rollers break out of their cage and ravage the rest of the rollers. Less warning.

(2) MSR carried a snap ring that replaced the old wire-ring to hold the bearing in the upright. IMHO it's a vastly superior solution. I had one wire-ring fail and the bearing scooted in past the ring. If you can't find them, let me know. I can measure a spare and it's probably available on McMaster-Carr.com. {When is another CSR going to acquire that MSR web site!?!?}

(3) Check out youtube for videos on replacing bearings. There may be variations, but the techniques are transferrable. A "big picture" thing to keep in mind is that if you don't want to hurt your bearings, when pulling/pushing them, do not create a sheer force between the outer and inner race. What that means is when pressing it on the hub, press on the inner race. When pressing it into the upright press on the outer race. Obvious to some, others learn the hard way.

Failing cotter pins are a flag for something bigger about to happen like a wheel about to exit the car at speed . Failing cotter pins is likely a symptom of an axle bolt that is stretching due to metal fatigue. I would suggest examining the bolt carefully and replacing it (or both) if there is any doubt about its integrity. Also I would suggest replacing the inner washer with the "new" thicker one. The old thinner one tends to deflect some.

Thanks for the input.
Axle bolt and nut were replaced in June. The ass'y was OK through two events at LRP. Noticed it started to impinge on the cotter pin at NHMS event last week. Found it broken off once home.
The LF was hit in an accident at the end of last season. Outer steering clevis was broken and the outer LCA spherical rod end was bent (all replaced). I am wondering what may have been deformed inside the hub which is causing the drag on the bolt which is un-threading it.
I'll be talking to MoDyn this week too.

Check your bearing retainers.

Thanks for all the replies. Root cause was a worn hub. Significant play with the axle bolt removed. New hub and wheel bearing installed by MoDy (quick turn around).
Hydraulic press going on my Christmas wish list.

+1 on the hydraulic press! I bought a junker unit from garbage freight for $100 last year, its been amazingly useful - even for changing SRF wheel bearings

I had that exact same thing happen. I originally thought that I had faulty cotter pins. Now I know what a worn hub can do.