Plugs & Caps

A Burnett & Hillman plug or cap is used in hydraulic systems to seal off ports, hoses, or fittings when they are not in use, during maintenance, or to protect the system from contamination.

You would typically use them when:

• Closing off unused ports on valves, manifolds, or cylinders.
• Protecting open connections during servicing or storage.
• Preventing fluid leaks when a line is disconnected.
• Keeping out dirt, dust, and moisture to avoid contamination.
• Pressure testing systems, where plugs can temporarily block off sections.
• In mobile equipment or industrial systems, where durability and reliability are critical.

Burnett & Hillman plugs and caps are used whenever you need to seal, protect, or isolate hydraulic connections - either temporarily during maintenance or permanently for unused ports.

Depressurise the system

• Switch off the hydraulic pump or power source.
• Operate the controls to release any residual pressure in the lines.
• Confirm zero pressure with a gauge if available.

Clean the area

• Wipe down the connection point to remove dirt, oil, or debris.
• This prevents contamination from entering the system when capped.

Select the correct plug or cap

• Match the thread type and size (BSP, NPT, JIC, Metric, etc.).
• Use only pressure-rated Burnett & Hillman plugs or caps designed for hydraulics - never makeshift items.

Fit the plug or cap

• Apply the correct sealing method (O-ring, bonded washer, or PTFE tape if tapered).
• Thread in by hand first to avoid cross-threading, then tighten with the appropriate tool.
• Do not overtighten, as this may damage threads or seals.

Check the seal

• If the system is to be re-pressurised, increase pressure gradually and inspect for leaks.
• If it’s for storage or transport, make sure caps/plugs are firmly seated to keep out dirt and moisture.

Tag if necessary

• In maintenance settings, mark or tag capped/plugged lines so operators know they’re isolated.