Modern Vespa

So, I was saving the easiest for last...

My engine is ready to come off save for the two mounting bolts and the hub.

I took the dustcover off the rear hub to discover the mangled remnants of a split-pin that is lodged in like it was set in concrete. The portions that were sticking out of the castellated nut crumbled to pieces as I tried to get some sort of grip on it to remove it... what's left just isn't budging.

Any thoughts on how to proceed to get the castellated nut off?

dremel tool + cutting disk ?

I've attacked stuck ones with a hammer and a flatblade screwdriver, basically trying to chisel off the stuck portions. Since the metal is malleable, eventually it breaks / snaps off like when you bend a paperclip too much.

Not enough room to get the disc that I have in the recess to get at the split pin.

Hmmm.... Maybe a trip to Home Depot to get a cutt-disc that's small enough to get in there.

Maybe this chisel to pieces route will be the ticket... sounds better than a trip to the store.

if you can grab it at all with a pair of needlenose, and just bend it back and forth until it snaps, that works.

Had the same problem with my rear hub. I let loose with WD40 and let the splitpin soak for a while. I had enough sticking out that I could get a good grip on but it wouldn't budge, so I bent and twisted one end till it broke off flush with the nut and hammered it with a small diameter nail with a flat filed end. It basically fit into the hole of the nut at a slight angle and broke free the pin so I could pull it out from the other end.

As above. Just keep bending and working at it and you'll get it. I had to do this a few weeks back and they can be a pig to remove.

Bend a hard, pointy instrument, like a pin punch or an awl, to a 90 degree angle (easier with heat), and use that to slip in between the nut and the hub, press against the pin remnants in the axle shaft, and bang them out using a hammer. Once you've got something sticking out the other side, you can grab it with needlenose pliers and work it out.

- Eric

Thanks all. Will report further...

Not that you have enough of it showing to do this, but in my experience with stuck cotter pins it's also easiest if you cut the loop end with wire cutters, and then work at pulling one half of the pin out only with needlenose pliers or whatever. Once one half is out, the second half comes out like butter.


EDIT:
On the same topic, do people know why ScooterMaintenance recommends wrapping the cotter/split pin OVER the axle rather than around the castle nut?

The accompanying text (Step 11)reads: The only thing I can figure is that by doing this the loop end of the cotter pin actually fits in more snuggly into the nut, lessening the chance of it moving about, and wrapping it over the axle keeps it snug. I don't otherwise see why it would be more safe than wrapping around the nut that I've seen in almost every other application of a cotter pin.

Any ideas?

The oval shape of the wire used for cotter pins makes it stronger in one direction than the other. Much like a 2x4 is stronger on edge than flat. Bent in the direction shown in the graphic, the strongest axis of the pin wire is perpendicular to the shear centrifugal force exerted by the edge of the castellated nut from the wheel spinning.

or in simple terms-- the pin is harder to bend or shear from that direction which means IF by chance your nut comes loose, the chances of the pin retaining it are greater when installed that way.

to the OP, get a 90* hook from where evers. insert tip and tap lightly with a hammer. that should knock the pin right out.

hope that helps,
-greasy