When selecting lubrication for bearings, what is a key factor to avoid over-lubrication?

• A. Never lubricate bearings.
• B. Always fill to the maximum capacity.
• C. Use the manufacturer-recommended lubricant type and quantity and observe lubrication intervals.
• D. Use any lubricant you have on hand.

Answer: (C)

The main idea here is that bearings must be lubricated with the right lubricant, in the right amount, and at the right times to maintain a proper protective film without causing harm. Using the manufacturer-recommended lubricant type and quantity, and following the suggested lubrication intervals, ensures the lubricant has the correct viscosity and additives for the bearing design, operating speed, and temperature. It also helps maintain the proper film thickness so metal surfaces don’t wear and heat is kept in check.

Over-lubrication can be just as damaging as under-lubrication: too much lubricant creates extra resistance, increases heat, can push lubricant into seals or housings, and can trap dirt or cause foaming, all of which degrade bearing performance. Following the recommended intervals prevents lubricant breakdown or contamination from building up and ensures fresh lubricant is supplied as needed.

Other options fail because they ignore these specifics. Not lubricating at all leaves bearings unprotected from wear and heat. Filling to the maximum regardless of conditions introduces excess lubricant and forces that can worsen overheating and contamination. Using any lubricant on hand ignores the important match between lubricant properties and bearing design, speeds, loads, and seals.