Info:
Performance
Application The Fastbrake valve was designed to be mounted at the tractor’s glad-hand on heavy-duty truck air
brake systems, in either the service or supply line.
Function Provides a quick exhaust of the trailer brake pressure when pedal pressure is relaxed, thereby
accelerating and coordinating trailer brakes with tractor brakes.
Forward Flow AT 70°F, the valve shall flow at least 9.0 SCFM with 2.0 PSIG applied to the trailer end of the valve with
trailer end open to atmosphere.
Exhaust Flow With 8.8 SCFM air flow applied to the trailer end, and the tractor end of the valve open to the atmosphere,
the pressure at the trailer end shall be 2.0 PSIG max.
Leakage At 5 and 125 PSIG air, the valve shall not leak more than 50 cc’s per minute from the exhaust port and roll
joint when tested by submersion in liquid.
By-pass Flow With tractor end of valve at a constant pressure of 10 PSIG, the flow through the valve from the trailer
side shall be 1.0 SCFM or more, with pressure differentials of 0.2 PSIG and 1.0 PSIG measured across
the valve. The valve may actuate prior to obtaining 1.0 PSIG across the valve (flow requirement may not
be achieved in this condition); this is acceptable performance.
Minimum Pressure for Actuation With the trailer side of the valve attached to a 50 cubic inch volume, and the tractor side connected to a
standard treadle valve by means of a standard coiled air brake hose with no other restrictions, the valve
shall actuate (exhaust air to atmosphere) when treadle is released to its spring return position from an
equilibrium pressure in the above system of 10 PSIG or greater.
Part Number 4000-1, Trailer side, nipple/male thread
4000-8D, Tractor side, nipple/male thread