[Walt Fricke]

Trackrat - The legendary Carroll Smith believed locking tabs don't work. He suggested "prevailing torque" nuts. I suspect nylocs, though less positive, would do.

I'd have to look at the other case half to be sure, but maybe the nut couldn't come all the way off anyway when the case is together? Only the upper nut is subject to tension with the pump turning. The force would vary with RPM, which is a minus for the nut staying put, but maybe not really enough to loosen a properly torqued regular nut?

One doesn't hear about these nuts coming loose, though.