H3050 Mackay 1840 Dunbier Hydraulic Coupling Master Cylinder | Marine Trailer Part

🔧 Product Description

Mackay Hydraulic Override-Coupling Master Cylinder – Part Number: H3050

A replacement hydraulic master cylinder for compatible trailer override couplings. Drawbar compression moves the piston, displacing brake fluid into the trailer's hydraulic calipers.

⚙️ Key Features

• Hydraulic trailer-brake master cylinder
• Designed for compatible override couplings
• Service replacement for worn or leaking cylinder
• Threaded outlet for hydraulic brake connection
• Reservoir and cap configuration as currently supplied

📏 Specifications

• Dunbier reference: 1840
• Bore, stroke, pushrod and outlet thread must match the original coupling
• Use the brake-fluid type specified for the complete system

🔄 Cross Reference & Related Parts

• Mackay: H3050
• Dunbier: 1840
• Hydraulic connector: H3074
• Flexible hose: H3068

🚤 Trailer Compatibility & Application

• Suitable for compatible hydraulic override couplings
• Not interchangeable with the master cylinder incorporated in every coupling model

🔌 Function

Creates hydraulic pressure when the coupling slide compresses during trailer overrun.

⚠️ Common Signs of Failure

• Brake fluid leaks
• Piston sticks or does not return
• Trailer braking is weak or inconsistent
• Fluid is contaminated or rusty
• Cylinder cannot hold pressure

🛠️ Installation & Safety

• Confirm bore, mounting and outlet before installation
• Flush contaminated lines
• Use fresh specified brake fluid
• Bleed all air from the system
• Test for leaks and progressive braking before road use

📦 Condition

• Brand new Mackay trailer component
• Supplied as one hydraulic master cylinder
• Supplied in original or equivalent packaging