Eaton AE99374E - Aeroquip 1801 Dust Plug -4 (1/4")

The Eaton AE99374E is an Aeroquip 1800/1801 Series Rubber Dust Plug (Female), AN size -4 (1/4"), for petroleum-based MIL-H-5606 and MIL-H-83282 hydraulic fluids environments. Where the dust cap protects the male coupling half, this dust plug inserts into the female (socket) half — filling the internal bore and protecting the valve seat, sealing surfaces, and internal geometry from contamination during maintenance and storage. The plug fills the female cavity to exclude particles, moisture, and FOD that could damage internal seals or introduce system contamination.

Female Receptacle Protection Design

• Plug body fills the female coupling cavity to seal the internal bore against contamination
• Nitrile rubber is compatible with petroleum-based MIL-H-5606 and MIL-H-83282 fluid residues
• Interference-fit installation requires no tools — hand-press installation and removal
• Sized specifically for the -4 (1/4") female coupling bore in the 1800 and 1801 Series

Constructed from natural rubber with a service temperature range of -40°F to +250°F (-40°C to +121°C), the AE99374E is a maintenance consumable used in conjunction with the matching rubber dust cap (male) for complete coupling protection. The plug and cap together ensure both halves of an open coupling are protected during servicing. Compatible with mil-h-5606 (red) and mil-h-83282 (fire-resistant) hydraulic fluids.

Coupling Protection Protocol Applications

• Internal protection of female coupling halves during hydraulic system servicing
• Paired with dust cap (male) for complete coupling set protection during open-system maintenance
• Storage protection for unused female coupling halves in MRO shop inventory
• FOD prevention for aircraft hydraulic system servo actuator circuits, instrument hydraulic lines, and brake accumulator systems maintenance