Motor Greasing Guide: How Much, How Often, Which Grease

Bearing greasing is the most common motor maintenance task — and the most commonly done wrong. Both too much and too little grease destroy bearings. This guide gives practical rules for greasing motor bearings correctly.

1. The Golden Rule: Less Is Often More

Over-greasing is a leading cause of bearing failure — excess grease churns, overheats, and breaks down, and can force out the seals. When in doubt, use less, more often, rather than a lot occasionally.

2. How Much Grease

Use the quantity specified for the bearing size — typically a small measured amount (grams), not "until it comes out." Larger bearings need more; small bearings need very little. The motor manufacturer's manual gives the correct quantity per bearing.

3. How Often

Greasing interval depends on motor size, speed, temperature, and environment. High-speed, hot, or dirty conditions need more frequent greasing; small motors in clean conditions much less. Many small motors have sealed-for-life bearings that need no greasing at all. Follow the nameplate/manual interval.

4. Which Grease

Use the grease type specified by the manufacturer — typically a quality lithium-complex bearing grease of the correct NLGI grade. Never mix incompatible greases — mixing can break down the lubricant and destroy the bearing. If changing grease type, purge the old grease fully.

5. Correct Procedure

1. Clean the grease nipple before greasing
2. With the motor running (if safe) or per procedure, add the measured quantity slowly
3. Open the drain plug (if fitted) to let old grease escape
4. Do not over-pump

6. Common Mistakes

• Over-greasing "to be safe" — the number-one error
• Mixing grease types
• Ignoring the schedule — both too often and never
• Greasing sealed bearings (they do not need it)

We supply genuine motor bearings and the correct grease, and advise on greasing schedules to maximise bearing life. Contact us or send a motor inquiry for expert guidance from our Mumbai and Ahmedabad teams.