SAE AS8791A-2003
Hydraulic and Pneumatic Retainers (Back-Up Rings), Polytetrafluoroethylene (PTFE) Resin

Standard No.

SAE AS8791A-2003

Release Date

2003

Published By

SAE - SAE International

Status

Be replaced

Replace By

SAE AS8791B-2009

Latest

SAE AS8791D-2020

Scope

This specification and part standard covers polytetrafluoroethylene (PTFE) resin material and the dimensional requirements for retainers (back-up rings) previously covered by AS8791 and AS8791/1 which superseded MIL-R-8791 and MIL-R-8791/1. The retainers are intended for use in hydraulic and pneumatic system components as anti-extrusion devices in conjunction with packings and O-rings. Use: Retainers to the dimensions in this specification are for use in glands to MIL-G-5514 (formerly MIL-P-5514C@ D and E Revisions) Gland Design@ Packings@ Hydraulic@ General Requirements for (Cancelled). They may also be used in glands to AS4716@ Gland Design@ O-Ring@ Packings and Other Elastomeric Seals@ however@ please refer to the Cautionary and Important Note 1 below. Caution: A new standard for back-up rings for use in glands to AS4716 is being developed. Until the standard is issued@ back-up rings to this specification can continue to be used in AS4716 glands. Important Note 1: The groove diameters for both rod and piston types to AS4716 differ from those to MIL-G-5514. Dash sizes 325 through 349 and 425 through 437 are identical. For all other sizes@ when using back-up rings to this specification in glands to AS4716@ the user should check to ensure each application is appropriate. Important Note 2: The dimensional requirements of this specification are the same as former Military Specification MIL-R-8791/1*. As such@ no attempt has been made to ensure the lap of the scarf-cut ends is adequately designed to be functionally satisfactory at low temperatures. Users should ensure satisfactory performance by testing at the appropriate low temperature for each application. *With the exception of dash sizes 004@ 005@ 006 where the angle of the scarf-cut has been changed for reasons of manufacturability. MIL-R-8791 (cancelled) and AS8791 (original issue) were used for the material specification for back-up rings to MIL-R-8791/1 (cancelled)@ AS8791/1@ and the following military standards that are inactive for new design: MS27595@ MS28773@ MS28774@ MS28782@ MS28783. This specification (AS8791) should be used as the material call-out for the standards listed above.

SAE AS8791A-2003 history

• 2020 SAE AS8791D-2020 Hydraulic and Pneumatic Retainers (Backup Rings), Polytetrafluoroethylene (PTFE) Resin
• 2014 SAE AS8791C-2014 Hydraulic and Pneumatic Retainers (Back-Up Rings)@ Polytetrafluoroethylene (PTFE) Resin
• 2009 SAE AS8791B-2009 Hydraulic and Pneumatic Retainers (Back-Up Rings), Polytetrafluoroethylene (PTFE) Resin
• 2003 SAE AS8791A-2003 Hydraulic and Pneumatic Retainers (Back-Up Rings), Polytetrafluoroethylene (PTFE) Resin
• 1997 SAE AS8791-1997 Retainer@ Packing@ Hydraulic and Pneumatic@ Tetrafluoroethylene Resin