The air headspace on steel circulating tanks can become rusty over time. Rust is a hard contaminant that can cause abrasion, promote oxidation and emulsify water. If there are no other options to control water ingression and rust, consider coating the area of the tank that is exposed to air and water condensation with a thin layer of grease compatible with the circulating oil. This should be done after a system drain and tank cleaning. The grease can be easily applied with a clean squeegee. (Michael Lofald, Predictive Maintenance Manager, SAPPI Fine Paper)

Join us for Machinery Lubrication Level I training in Atlanta, Georgia on October 16-18.

We send $100 for each tip published. Submit your tip.

Four shots every 28 days. It couldn't get any simpler than that, right? At least I thought so at first.

Two years ago, when I was asked to manage our facility's machinery lubrication program, I had limited experience with lubrication. My manager suggested I refocus the program on the basics, which I agreed was a reasonable starting point.

I must admit that at first, I thought of lubrication as a menial task, as many do. My attitude quickly changed as I realized the importance of lubrication in a manufacturing facility.

Click to Continue

Test your knowledge and prepare for ICML lubrication and oil analysis certification.

Question: Which is more sensitive to silt-size particles? Journal bearings or rolling element bearings?

Get the answer.

"Is there a standard method for determining if and when a bearing should be cleaned and repacked?"

Given the practical challenges of hand-packing a bearing with any hope of maintaining grease and bearing cleanliness, it is often best to avoid opening a bearing to clean and repack. Simply stated, the benefit practically exceeds the costs and risks. However, if circumstances exist where this must be done, then some thoughtful planning is justified.

We should look at the issue as a two-part problem. The first issue is if/when to repack a bearing. If a bearing is intended to be grease-lubricated, then it would be best to include a zerk or similar fitting to enable replenishment without opening the bearing cavity.

When the bearing is replenished according to sound engineering principles (right product quality, right product selection, right amount, right frequency, no cross-contamination) the bearing does not require disassembly, cleaning and repacking to maintain lubricant and bearing health. If the bearing cannot be configured with a zerk and a relief, and a "clean and repack" event is the ONLY option, then scheduling the activity becomes a judgment call based on a multitude of factors as noted below.

The second part of the question is about whether there is a standardized approach for making this decision. After reviewing a few well-respected lubrication texts, and speaking with two well-known bearing manufacturers, the author concludes that there is no recognized standard with which to make a decision to disassemble and repack a bearing.

Several factors may influence the selected repack frequency decision, including the quality of the environment near where the work is to be done, the quality of the grease removed during previous repack events, the size of the housing, the extent to which spent grease has filled up available housing space, flexibility in configuring the housing for routine replenishment, flexibility in configuring the housing to "vent" spent grease during replenishment, evidence of bearing stress (increase in temperature, increase in high frequency energy) ease for grease sampling and availability of grease analysis.

The use of acoustics or other high-frequency metrics can be most helpful in supporting the scheduled frequency decision if a manual repack must occur.

Submit a question | Discuss on Message Boards