Error 1: Over-greasing — more grease is not better lubrication
Over-greasing is the most widespread error and one of the most costly. When a bearing receives more grease than it can accommodate, the excess generates rotation resistance, increases operating temperature, and can cause seal failure. The extra temperature accelerates oxidation of the remaining grease.
A correctly filled bearing should contain grease in 30–50% of its free space. The correct amount depends on bearing size, speed, and temperature. An automatic greaser with a controlled volume eliminates this error entirely.
Sign of over-greasing: abnormally high temperature in the bearing in the first few minutes after relubrication, followed by stabilisation. The excess grease is expelled and the temperature drops, but seal damage may already have occurred.
Error 2: Mixing incompatible greases
Greases are not universally compatible with each other. Mixing incompatible thickeners can cause the structure of both greases to break down: the result is a liquefied product that does not lubricate and leaves the lubrication point. The worst aspect of this error is that the failure is not immediate: it may take weeks to manifest, during which time the bearing operates without adequate lubricating film.
Lithium and calcium thickeners are moderately compatible. Lithium and polyurea are incompatible. Calcium and bentonite are also incompatible. Before changing supplier or product, always verify compatibility.
- If no compatibility information is available, clean the point completely before applying the new grease.
- In sealed-for-life bearings, it is not possible to change the grease: if the original grease is unsuitable, the bearing must be replaced.
- The colour of the grease is NOT an indicator of compatibility. Two greases of the same colour may be incompatible.
Error 3: Fixed relubrication intervals without adjustment for conditions
Bearing manufacturer relubrication intervals are based on reference conditions: normal temperature, nominal load, low humidity. In real industry, all these conditions are rarely present simultaneously.
A bearing operating at 80°C instead of 40°C needs half the relubrication interval. One operating in a humid environment needs even higher frequency. Applying the standard interval under severe conditions means accepting a reduced bearing service life.
Practical formula: for every 15°C above the manufacturer's reference temperature, halve the relubrication interval.
Error 4: A single lubricant for the entire plant
The drive for stock simplification leads many plants to reduce their lubricant range to one or two universal products. The savings in stock management are more than offset by the accelerated deterioration of the most demanding equipment.
A universal lubricant may be the right choice for 70% of a plant's lubrication points. But the remaining 30% — high-temperature, high-load, water-contact, or high-speed points — require a specific formulation. The cost of the specialist lubricant for that 30% is a fraction of the cost of a prematurely failing bearing.
Error 5: Ignoring lubricant storage conditions
A lubricant stored incorrectly can deteriorate before reaching the lubrication point. Temperature is the most critical factor: storage at temperatures above 40°C degrades antioxidant additives and accelerates base oil oxidation. Cold/hot temperature cycles in closed drums can cause internal water condensation.
High-quality lubricants are especially sensitive: their latest-generation additives are more costly and also more susceptible to degradation from improper storage.
- Recommended storage temperature: 10–25°C, away from direct sunlight.
- Drums should be stored horizontally to prevent the bung from contacting the ground and allowing moisture ingress.
- Stock rotation: FIFO (First In, First Out). Check the expiry date before use.
- Opened lubricants should be consumed within 6–12 months depending on type.
None of these errors requires expensive equipment to resolve. They require procedure, training, and maintenance discipline. A lubrication audit identifies in a few hours which errors are being made in a plant and what their economic impact is. At LUBESOLUT, we offer this service as part of our advisory process.
Request a lubrication audit