Product Line Product Protection & Finishing Threaded Hydraulic Caps & Plugs

Threaded Hydraulic Caps & Plugs

Caps’n Plugs carries a variety of threaded caps, plugs and other hydraulic parts available in polyethylene or aluminum to protect threaded fittings from dirt or contamination.

Flared-Fitting Plugs HF Series

Flared-Fitting Plugs HF Series

Threaded (NF & UN) Plugs TF Series

Threaded (NF & UN) Plugs TF Series

Inverted Flared-Fitting Plugs HT Series

Inverted Flared-Fitting Plugs HT Series

Flareless Tube & Nut Assembly Plugs PDE Series

Flareless Tube & Nut Assembly Plugs PDE Series

SAE O-Ring Port Plugs PDO Series

SAE O-Ring Port Plugs PDO Series

Unified Sealing Plug UT Series

Unified Sealing Plug UT Series

Flat-Face O-Ring Plugs PDF Series

Flat-Face O-Ring Plugs PDF Series

Threaded Plugs TH Series

Threaded Plugs TH Series

Threaded Plugs TP-F Series

Threaded Plugs TP-F Series

Threaded Plugs TP Series

Threaded Plugs TP Series

Threaded Cap (straight) TC Series

Threaded Cap (Straight) TC Series

Threaded Aluminum Plugs ADP Series

Aluminum Flareless Threaded Plugs ADP Series

Threaded Aluminum Plugs ASP Series

Aluminum Flared Fitting Threaded Plugs ASP Series

Threaded Aluminum Plugs ASC Series

Aluminum Flared Fitting Threaded Caps ASC Series

Threaded Aluminum Plugs AFO Series

Aluminum Flat Faced Threaded Plugs AFO Series

Finishing Flanges

Finishing Flanges

Hose Collars

Hose Collars

HB Hose Bend Restrictors

HB Hose Bend Restrictors


Flared-Fitting Plugs HF Series

Build with a knurled head, these plugs protect both flared-fittings and 37° flared fittings without a gasket. Applicable for low pressure testing. Various sizes available.

Threaded (NF & UN) Plugs TF Series

This general purpose polypropylene threaded plug is used in a variety of applications and can be tightened by hand. Various sizes available.

Inverted Flared-Fitting Plugs HT Series

Built with a knurled head for easy application, these inverted fitting plugs are designed to protect inverted flare fittings. Various sizes available.

Flareless Tube & Nut Assembly Plugs PDE Series

These polyethylene plastic plugs can be hand-tightened and will fit both MS-21921 tube and nut assemblies. Various sizes available.

SAE O-Ring Port Plugs PDO Series

Prevent oil leakage or contamination of your SAE straight-threaded O-Ring type ports and MIL-MS-33649 bosses on fluid power components with these knurled polyethylene plugs. Various sizes available.

Unified Sealing Plug UT Series

Designed with a unique Tight Fit™ sealing lip along with five complete threads, this unified sealing plug prevents contamination in ports, without the need of an o-ring. Various sizes available.

Flat-Face O-Ring Plugs PDF Series

Typically used the hydraulic and pneumatic industries, these flat-faced O-ring fittings are made from polyethylene and can be installed by hand or mechanically. Various sizes available.

Threaded Plugs TH Series

Typically used to keep contaminants and moisture from ports, these threaded plugs are built with a socket design for thread protection during pressure testing and in-plant processing. Various sizes available.

Threaded Plugs TP-F Series

Commonly used during low-pressure testing and in-plant processing, these threaded plugs are built with a flange design to protect the circumference of the port while protecting threads from contamination and moisture. Various sizes available.

Threaded Plugs TP Series

Built with a square head for easy application, these threaded plugs protect ports against contamination and are ideal for low-pressure testing and in-house handling. Various sizes available.

Threaded Cap (straight) TC Series

Ideal for masking during painting or plating applications, these threaded caps protect straight threads and fittings and deter contaminates. Various sizes available.

UN & UNS Plugs DP Series

Built with rolled threads to to allow for push-threaded application, these UN and UNS plugs seal out contaminants and were originally made for use with aircraft and hydraulic equipment. Various sizes available.

Threaded Plugs RP Series

Built with a lip on the flange to keep contaminants out of SAE straight-threaded ports, these polyethylene plugs have an integral o-ring and a slotted head for tightening. Various sizes available.

Threaded Cap (UN/UNS) DC Series

Specifically designed for aircraft and hydraulic equipment applications, these threaded caps seal out contaminants and can be either pushed or threaded on. Meets UN and UNS specifications. Various sizes available.

Threaded Aluminum Plugs ADP Series

The ADP series threaded aluminum plugs offer a dimpled nose section to form a low-pressure seal with tube ends and hose assemblies.

Threaded Aluminum Plugs ASP Series

Specifically designed to protect 37° flared fittings and straight-threaded ports, these aluminum alloy ASP plugs are built with a nose section that seals on flared fittings without a gasket. Various sizes available.

Threaded Aluminum Plugs ASC Series

The ASC Series threaded aluminum caps for threaded flared fittings are designed with a nose-section that forms a low-pressure seal. Optional sealing discs for a positive seal available.

Threaded Aluminum Plugs AFO Series

Built for positive, metal to metal threaded protection of fluid lines and fittings, these aluminum plugs also have optional neoprene gaskets, which are available in Butyl or Buna N Rubber. Various sizes available.

Finishing Flanges

Most frequently used in plumbing, water heaters, refrigeration and machinery industries, these low-cost replacements for metal flanges provide a durable and long-lasting finish. Multiple sizes available.

Hose Collars

Designed as a hose and tube-end cover, these flanged washers prevent working fluid from leaking after implementation and are extra thick for heavy-duty applications. Multiple sizes available.

HB Hose Bend Restrictors

Typically used to reduce the bending stress near the hose-coupling junction, these durable add-ons remove the need for costly adhesives or clamps, extending the life of a variety of hydraulic and pressure-washer hoses.