I've found Vanner equalizer schematics on the internet in the past. If it's just a stud it's probably a mechanical repair.
Thanks, Brian. I haven't had a chance to take it off the bus and it's down in a place where it's hard to see but it feels like the stud is broken out of some part of the housing or other solid part. When I can remove wiring to get to it, I will be able to see better. Google pointed me toward some of the schematics and that should help. But it would be kinda comforting to know that there's somebody out there who actually knows what they're doing when I get over my head (and I can get over my head in about 3" of them electrictron things).