Tracked a stubborn rattle on our case erector and noticed yellow dabs on a bunch of fasteners - some bridging nut to flange, some just dotting the head. Is that always a torque witness mark or do certain OEMs use it for QA cycles too, and would you trust it when deciding what to re-torque after a teardown?
Yellow can be torque-seal or just QA/shift ID — it’s not a golden ticket — so nick it with a pick; if it cracks like brittle lacquer, it was a witness mark, if it smears it’s just a paint pen. After teardown, re-torque to spec and add your own dated torque-seal; does it crack when you score it?
On a lot of case erectors, that yellow also flags set-and-leave points like eccentric cams or chain tensioners, not just a witness line. Building on @emma39, I’d torque critical joints to the manual spec and then add your own paint after reassembly; if the dab is on a slotted bracket or an adjustment lock, treat it like a Post-it, not a torque spec. What make/model is the erector so we can tell if their color map is QA-cycle or adjustment marking?
Wouldn’t trust it without the OEM legend; that yellow doubles as warranty/tamper paint and shift/QA tallies on some erectors. @emma39’s right on set-and-leave points, but for your rattle I’d photo-map the “bridging nut to flange” marks, strip the old dabs, reassemble to the correct values, then add your own line across each joint. If any line drifts on run-up, that’s your re-tighten target.