KCF Technologies Blog

Mike on Maintenance: Overgreasing

CAUTION: The following BLOG may contain strong content with words like OVER-GREASING, BEARING FAILURE, SEAL DAMAGE. If these words offend you please read on.

I am by no means an expert on machine lubrication, just a tech in the real world that “turned the wrenches”.

“The more grease I put in the bearings the better it will work” and "putting in more grease now I will not have to lubricate as often" are common thoughts most techs have about lubrication. WRONG.

Let’s cut to the chase. Over-greasing can lead to high operating temperatures and in the case of electric motors can cause energy loss and collapse the bearing shields. The excess grease can cause heat to build up in the bearing and the grease to churn and possibly cause your rolling elements to skid. This can cause oil bled (the separation of oil from the thickener).

Consider that some grease guns can produce as much as 6000 PSI and higher. The seals don't have a chance with that much pressure. Consider that lip seals usually fail around 500 PSI and when you are lubricating pump bearings, and compromising the seals can lead to leaking and contaminants like water and dirt entering the seal.

This short and simple calculation will get you in the ball park with how much grease to apply:
G = 0.114 x D x B

Where G = the amount of grease in ounces
             D = the bore diameter in inches
             B = the bearing width in inches

We will continue to discuss our over-greasing shortfalls and some preventative measures in my next blog.

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