The Hallite 775 double-acting piston seal is a compact seal for light to medium-duty applications and designed to fit two housing standards; one for standard O-ring grooves, the second for grooves designed for an O-ring and two back-up rings. The advanced face geometry gives the Hallite 775 single-acting capabilities making it an excellent choice for double-acting applications where minimal dynamic leakage is required.

The Hallite 775 is comprised of a tough polyurethane face seal which is pre-loaded by a rectangular cross-section NBR expander. The standard material is suitable for hydraulic mineral oil applications.

The Hallite 775 can be used on SG iron pistons or on pistons where there is an adequate remote bearing, such as the Hallite 506, 533, and 87 bearings.

  • Unit of measurement:
Unit of measurement:

Max pressure

350 Bar

Temp range


Max speed

  • Recomended
  • Possible
  • Not Suitable

* For fluid types marked as possible, please call our team of experts on +44 208 941 2244 to talk through your requirements and determine if this seal is the most suitable for your needs.

  Dynamic application Static application
Fluids based on mineral oil    
Any Recommended Recommended
Waterbased fluids    
HFA (5/95) Not suitable Not suitable
HFB (60/40 invert emulsion) Not suitable Not suitable
HFC (water glycol) Not suitable Not suitable
Water Not suitable Not suitable
Other fluid types    
Air/Nitrogen Possible Possible
HFD (Phosphate ester ARYL Type) Not suitable Not suitable
Synthetic esters (HEES, HFDU) Recommended Recommended