Motor Vehicle Brake Fluid Based Upon Glycols, Glycol Ethers and the Corresponding Borates
This SAE Standard covers motor vehicle brake fluids of the nonpetroleum type, based upon glycols, glycol ethers, and borates of glycolethers, and appropriate inhibitors, for use in the braking system of any motor vehicle such as a passenger car, truck, bus, or trailer. These fluids are not intended for use under arctic conditions. These fluids are designed for use in braking systems fitted with rubber cups and seals made from styrene-butadiene rubber (SBR), or a terpolymer of ethylene, propylene, and a diene (EPDM).
Document revision was considered necessary to harmonize this and the SAE J1703 specification which currently includes significant differences in test procedures and requirements.
Specification requirements are made clearer and easier to find using a tabulated format. Requirements for SAE J1704 viscosity at −40 °C have been expanded to include a low viscosity fluid.
Greater specification detail is given for the referee materials used in the test methods and is issued in a separate document to simplify future document revisions. Appendix C is further expanded to include information on the Rubber Test Cups (RM-3a) in Section C.4, for their preparation, handling, and storage, and Figure C1, for their design dimensions for the rubber cups.
The stroking test has been withdrawn as it no longer reflects current technology. However, it is considered important that this document includes archival information on the test and its’ characteristics, should the test be redesigned for modern and future technologies. See Appendix G.