🔍 Key Concepts

• Mechanical shaft seal construction (mating/seating faces, stationary vs rotating element, spring action) • Purpose of spring pressure in keeping faces in contact without excessive wear • Why running a pump dry or using abrasive materials on seal faces is harmful

💭 Think About

• Which choice helps the seal faces stay in light, even contact so they can seal, but does NOT damage or overheat them? • What would happen to precision-lapped seal faces if you used emery cloth or ran the pump without liquid? • Is it ever safe practice to make mechanical adjustments close to rotating machinery while it is running?

✅ Before You Answer

• Eliminate any option that involves intentional damage or excessive wear to sealing faces. • Eliminate any option that creates a clear safety hazard to personnel. • Focus on the option that refers to proper contact pressure between seal faces rather than break‑in or surface modification.