The Groz HC/14/4/N (often referred to simply as the Professional 4-Jaw Coupler) is the standard high-pressure connection point between a grease gun and a grease nipple (Zerk fitting). It is designed to provide a leak-proof seal under extreme pressure, ensuring that grease actually enters the bearing rather than "shirting" out the sides.Technical SpecificationsThread Size: 1/8" BSPT (Standard for most grease gun hoses and pipes).Maximum Pressure: 6,000 PSI (413 BAR).Construction: Heat-treated spring steel jaws with a chrome-plated finish for corrosion resistance.Outside Diameter: 15 mm (Standard slim profile).Length: 38 mm.Key Features4-Jaw Locking Mechanism: Unlike cheaper 3-jaw versions, the 4-jaw design provides a more balanced, 360-degree grip on the grease nipple. This significantly reduces the chances of the coupler popping off under high pressure.Spring-Loaded Ball Check: Features a built-in spring-loaded ball that acts as a check valve, preventing grease from leaking back out of the coupler after you disconnect.Hardened Jaws: The jaws are manufactured from hardened spring steel, which maintains its tension over thousands of duty cycles, preventing the "loose fit" common with low-quality alternatives.Narrow Profile: The 15 mm diameter allows the coupler to fit into recessed or tight spaces where bulkier quick-release couplers might struggle to reach.Usage & Maintenance TipsConnecting: Push the coupler straight onto the grease nipple. You should feel a distinct "click" as the jaws snap over the head of the fitting.Disconnecting: To remove the coupler, tilt it slightly to one side and then pull. Pulling perfectly straight back can sometimes cause the jaws to "lock" even tighter due to internal pressure.Pressure Relief: If the coupler is stuck on a nipple due to high back-pressure (common when a nipple is blocked), try unscrewing the coupler from the grease gun hose by half a turn to vent the pressure.Cleaning: Periodically wipe the inside of the coupler with a clean rag. Grit trapped inside the jaws is the leading cause of "leaky" connections and damaged grease nipples.
