Adding a grease extension hose to your grease fitting requires a change in how you grease your bearings. Grease is extremely viscous and it takes time for grease to move through a grease extension hose from the grease fitting end to the bearing. The longer the hose, the longer this movement takes.
When grease is pumped into the grease fitting end of the hose, the hose expands slightly under the increased grease pressure. Grease moves slowly through the hose as the hose contracts to return to its normal size.
It will no longer be possible to grease bearings by “feeling” for an increase in grease pressure, or by depending on the sound of a bearing to indicate that adequate grease has been added. These methods will no longer be possible because these indicators will be delayed significantly by the slow movement of grease toward the bearing. If the lubrication technician continues to add grease until these indicators are present, far too much grease has been added to the hose. Over the next several minutes, this excessive grease will find its way into the bearing – increasing pressure on bearing seals or leaking from the bearing causing contamination of other machine parts.
When greasing a bearing with a grease extension hose added, a known volume of grease must be added. The lubrication technician should determine the proper volume of grease to add to each bearing and pump exactly that amount of grease – using a grease gun of with a known volume of grease from each pump of the grease gun lever.
Once this volume of grease has been added, the grease will slowly flow into the bearing over the next several minutes.
Disclaimer: Every condition found in the field is unique. Rules of thumb and best practices described here may not work in all situations. We recommend consulting an engineer or lubrication specialist for advice on your specific situation.