GREASE BLEEDING

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DOES ANYONE KNOW WHAT CAUSES GREASES TO BLEED? I UNDERSTAND IT IS WHEN THE OIL
SEPARATES FROM THE THICKENER, BUT WHY DO SOME GREASES BLEED WHILE OTHERS DO NOT.
BOUGHT SOME AMSOIL SERIES 2000 GREASE AND LOADED IT TO MY GREASE GUN AND 2 WEEKS
LATER THE GREASE WAS BLEEDING HEAVILY OUT THE BACK OF MY GREASE GUN FROM WHERE I
HAD IT HANGING. WHAT CAUSES THIS. THANKS, MIKEYOILNUTT.
 
I have the same thing happening my supply of Racing Grease and I position the gun down where the "grease out" side for the snorkel is down.

Grease is a "porous" mixture and oil globules do seem to migrate or "diffuse" through the thickeners. I have yet to see a grease that doesn't do that when stored in a hot area, such as my steel shed. I usually take a paint stirring stick and remix the oil and thickener in a large plastic bowl before loading into a grease gun.
 
Rule #1, especially with synthetic greases, is to back off the plunger from your grease gun when not in use! ALL grease is made to 'bleed' to some degree. Greases are generally composed of 90% oil and 10% "thickener" or sponge. When you squeeze a sponge with oil in it, the oil will come out in liquid form. Same with grease. Squeeze it as in a bearing and the oil will come out and lubricate; we are lubricating with oil just as if you had an oil can and were applying oil drops at a time. When the pressure is off the grease, the sponge or thickener soaks the oil back into the body/sponge. Synthetic greases may be a little more prone to do this in a grease gun that has been left cocked/loaded as, in the case of the Amsoil, a pretty thin base oil probably used in the grease and the PAO base oil may have softened or shrunk the rubber seal a bit.
Back to rule #1. Irrespective of whether it is syn or mineral, always back the plunger off completely when the gun is not in use. If not, you will find the grease's lubricant, the oil, on the floor of your oil room and may be left with nothing but thickener in the gun. Thickeners do not lubricate well...
George Morrison, STLE CLS
 
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