View Grease SpecificationsGrease ZerksA Zerk is a Grease Fitting. It was named after Oscar Zerk who patented the zerk in 1929. A zerk is a small hydraulic check valve used on bearings and similar mechanical assemblies to supply lubricant to internal parts. The valve opens under pressure to allow lubricant to pass through a channel and be forced into the voids of the bearing. When the pressure ceases, the ball returns to its closed position. The ball excludes dirt and functions as a check valve to prevent grease escaping back out of the fitting. The ball is almost flush with the surface of the fitting so that it can be wiped clean to reduce the amount of debris carried with the grease into the bearing. The common convex shape of the fitting allows the concave tip of the grease gun to seal against the fitting easily from many angles, yet with a sufficiently tight seal to force the pressured grease to move the ball and enter the fitting, rather than simply oozing past this temporary annular ring-shaped seal. Browse our selection of grease zerks for sale! Meets SAE J-534C 8000 psi Maximum Pressure Exceeds 12 Hour Salt Spray |
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