Tapping or whacking a sticky solenoid, jammed slide, stuck relay or reluctant part until it moves. It works surprisingly often because it frees debris, breaks static friction or reseats a connection, but it treats a symptom rather than the cause. The deadpan formal name is the joke.
Heard on the job
Coolant valve sticks again, give it some percussive maintenance with the handle and put in a work order.
Also heard as
- percussive adjustment