The Hallite 770 double-acting piston seal is a compact, low friction seal for light to medium-duty applications designed to fit standard inch O-ring housings.

The Hallite 770 is comprised of a tough, self-lubricated thermoplastic elastomeric face seal which is pre-loaded by a rectangular cross-section NBR expander. The standard material is only suitable for hydraulic mineral oil applications. Other material options are available for water-based (HFA and HFB) fluids and synthetic esters (HEES). For intermittent single-acting applications and in certain sizes, we recommend using Hythane® 181 for the face material.

The Hallite 770 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. For further details of bearing grooves, please refer to the appropriate product data sheet.

  • Unit of measurement:
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  • Recomended
  • Possible
  • Not Suitable

* For fluid types marked as possible, please call our team of experts on 1-800-668-7970 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) Possible Possible
HFB (60/40 invert emulsion) Possible Possible
HFC (water glycol) Not suitable Not suitable
Water Possible Possible
Other fluid types    
Air/Nitrogen Possible Possible
HFD (Phosphate ester ARYL Type) Not suitable Not suitable
Synthetic esters (HEES, HFDU) Recommended Recommended