U Packing

Leather “U” packings seal reciprocating pistons, plungers, and ram applications where a balanced sealing profile is required. Unlike “U-cups” made from homogeneous synthetic materials, leather U packings feature a natural fiber matrix that delivers flexibility, resilience, and adaptability to wear conditions.

Typical Applications
Used widely in hydraulic presses, industrial rams, and legacy machinery where piston movement demands a durable seal. The balanced design ensures sealing on both inner and outer diameters.

Material & Impregnation
Leather U packings at Monarch-McLaren can be impregnated with Thiokol, carnauba wax, silicone, or other agents to enhance performance in specific service settings. Impregnation improves abrasion resistance and extends operating life.

Key Benefits

• Custom sizes from 1″ up to larger diameters available.
• Natural material reduces heat build-up and friction.
• Excellent conformity to cylinder walls, even with minor wear.
• Suitable for moderate pressure applications.

Why Leather Matters in U Packing
Leather’s inherent structure allows the packing to maintain seal integrity under dynamic motion and fluctuating service conditions while resisting abrasion better than many synthetics in similar applications.