Eaton AE99373E - Aeroquip 1801 Dust Cap -4 (1/4")

The Eaton AE99373E is an Aeroquip 1800/1801 Series Rubber Dust Cap (Male), AN size -4 (1/4"), for petroleum-based MIL-H-5606 and MIL-H-83282 hydraulic fluids environments. This rubber cap seals the male coupling half of an Aeroquip 1800 or 1801 Series quick-disconnect when the coupling is open — protecting the coupling face, valve seat, and seals from airborne contaminants, hydraulic fluid splatter, and foreign object debris (FOD) during maintenance and ground service intervals. The interference-fit design installs without tools.

Rubber Interference-Fit Protection

• Nitrile rubber compound is compatible with MIL-H-5606 and MIL-H-83282 hydraulic fluid environments
• Interference-fit body secures the cap to the male coupling half without fasteners
• Seals the coupling face and valve against airborne particles, moisture, and FOD
• Sized for the -4 (1/4") male coupling half across the 1800 and 1801 Series

Constructed from natural rubber for durability across -40°F to +250°F (-40°C to +121°C), the AE99373E is a cost-effective protective accessory required by maintenance procedures whenever a coupling is opened. Compatible with mil-h-5606 (red) and mil-h-83282 (fire-resistant) hydraulic fluids. A fleet maintenance inventory staple for military and commercial aircraft hydraulic coupling protection during maintenance, storage, and ground service intervals.

Maintenance and Ground Service Applications

• Protection of open male coupling halves during hydraulic system servicing
• Required fitment on unoccupied 1800/1801 Series male ports during storage
• FOD prevention during aircraft ground operations and maintenance
• Fleet maintenance consumable for hydraulic servo actuator circuits, instrument hydraulic lines, and brake accumulator systems