March 87 C wheelnut "locking ring"?

[stownsen914]

Some of you may have seen my threads over the past several years as I learned about keeping the wheelnuts on my GT racer that uses March 87C Indy uprights and hubs.

I noticed an interesting part on an exploded parts diagram I got courtesy of R Pare that shows a "locking ring" that sits just outboard of the wheelnut. The diagram doesn't show it in enough detail to understand how it works. Anyone know? (Sorry for the upside down pic.)

[tlracer]

Looking at the groove machined into part #29, it looked like #2 is a snap ring that fits into there, to retain #29 into the axle #5, assuming the axle has an equivalent internal groove.

Whether that was done to allow #29 to be removed /replaced if it became damaged, whilst not needing to replace the entire axle?

[stownsen914]

Correct that #29 is a separate part, presumably to allow its replacement as a higher wear part. But it appears to be just pressed into the hub. I looked at it for a few minutes today and can't find any evidence of an internal or external clip securing it.

So I'm back to thinking the locking ring may be intended to secure the wheelnut. Just not sure how?

[tlracer]

If #29 is only pressed in, how is it retained?

Turning to the locking ring, if it is for nut retention could it be a spacer between the outside face of the nut and the retaining pin?

Being split - as the diagram appears to show it - would allow it to come off easily as the nut was gunned off?

I admit this seems very unlikely as they would need to be specific to each corner to allow for wear, wheel centre thickness, etc.

[stownsen914]

I can't find any evidence of retention for #29 other than press fit. Which seems odd.

[Dstarbuck]

Looks just like my Lola wheel hubs, but your diagram doesn't show the rest of the locking mechanism (at least if it is like mine). There should be a large spring that keeps the "piston" (29) seated against the circlip which goes on the hub after the spring, bearings, and piaton are inserted. The 1/4" ball bearings go into the hub from the inside.

The groove in 29 let's the ball bearings fall into it when 29 is depressed by the proper wheel nut socket, then letting the wheel nut spin off. If 29 isn't depressed, the wheel nut will not get past the ball bearings.

Not sure why it's not letting me post pictures on this thread, but if you go into my t94 build In the BOSS section, I have a picture of the hub disassembled as well as the parts breakdown.

[stownsen914]

Looks just like my Lola wheel hubs, but your diagram doesn't show the rest of the locking mechanism (at least if it is like mine). There should be a large spring that keeps the "piston" (29) seated against the circlip which goes on the hub after the spring, bearings, and piaton are inserted. The 1/4" ball bearings go into the hub from the inside.

The groove in 29 let's the ball bearings fall into it when 29 is depressed by the proper wheel nut socket, then letting the wheel nut spin off. If 29 isn't depressed, the wheel nut will not get past the ball bearings.

Not sure why it's not letting me post pictures on this thread, but if you go into my t94 build In the BOSS section, I have a picture of the hub disassembled as well as the parts breakdown.

Interesting - this is very plausible, and it is consistent with the design of the snout (#29 in the diagram). So a design sort of a like a quick disconnect air hose with balls keeping the wheel nut captive on the axle. The holes in #29 look about the right size to hold small ball bearings, and the ID of #29 has smooth grooves that could accommodate parts on the. Possibly related, the outboard end of the wheel nuts also have a rounded groove in the ID that might be designed to accommodate a ball protruding from the holes in #29.

[Dstarbuck]

A few of my hubs were actually missing the snap rings, but the snout of the hub (#5) was dented in enough from years of use to keep it retained in there without the clips. Took a bit of filing/sanding the ID to allow me to pry the lock cylinder out of the hub.

I also have a stripped wheel nut from a previous owner trying to muscle it off the hub without realizing that there was a locking mechanism in place, so it's safe to say the 3 little 1/4" ball bearings do their job.

[stownsen914]

I'd be curious to know more about the locking mechanism, and parts to make it, for a March 87C. Sounds like mine is similar to Dstarbuck's Lola. I googled and found a pic of another March showing a somewhat different looking setup. Here's a pic of a front axle from my car.

[Dstarbuck]

That looks pretty close to mine. All your missing is the sliding portion that goes inside, a spring, the bearings and a c clip. The outward pressure of the piston/sliding portion via the spring keeps it riding against the clip.

I just ordered 4 new clips from pitlane, and I'll report the dimensions when they arrive in a week or two.