This SAE Recommended Practice establishes minimum tolerance requirements for pilot operated and mechanically actuated modulating type valves, and through type valves used in the service brake control system when tested in accordance with the test procedure outlined in SAE J1859. This document applies to the nominal input-output characteristics as specified by vehicle original equipment manufacturer and labeled by the valve manufacturer as outlined in SAE J1860. The tolerance requirements will include: A. Crack (opening) pressure or force b. Pressure differential (input-output)
Updates to this document include the following changes. 1.a. Added explanation to the crack pressure. 1.1 Changed operating pressure from 120 psi to 135 psi to agree with SAE J1410. 4.1.1 Deleted tolerance for pressure range from 6.9 to 27.6 kPa. Changed greater than 27.6 kPa to greater than 6.9 kPa.