Groz Grease Gun Coupler 4-Jaw

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 Specifications

• Thread 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 Features

• 4-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 Tips

1. Connecting: Push the coupler straight onto the grease nipple. You should feel a distinct "click" as the jaws snap over the head of the fitting.
2. 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.
3. 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.
4. 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.