Power Products 800333P QR-L inline quick release valve replaces Bendix 800333 in heavy-duty truck and trailer air-brake systems. The valve threads inline between the brake-application source and the service brake chambers — most often direct-mounted to the tractor protection valve — and dumps trapped air locally on release so the chambers exhaust faster than they could through the foot valve alone. Both ports are 1/2"-14 NPT. Signs You Need a New Quick Release Valve Slow brake release — chambers stay applied after pedal release Brake drag complaints from drivers despite working chambers Audible air leak from the valve exhaust port Inconsistent release between front and rear axles Dust or debris visible at exhaust port (worn diaphragm) Specifications Manufacturer Power Products Part Number 800333P Part Type QR-L Inline Quick Release Valve, Direct Mount Supply Port 1/2"-14 NPT Male Delivery Port 1/2"-14 NPT Female Differential Pressure 0 psi (zero hysteresis) Max Operating Temperature 200°F (93°C) Features Dust shields (2), no thread sealant required Cross References This valve replaces or is equivalent to the following part numbers: Bendix: 800333 (QR-L), BX800333 GT Development: 4000-6 Phillips: 12-811 Sloan: 401146 Tectran: 801095 Automann: 170.800333 Dayton Parts: AV800333 Euclid: E-BN800333N New Star: S-C069 Keene: K800333 Applications This QR-L quick release valve is used wherever fast air-chamber exhaust is required on FMVSS-121 air-brake systems: Tractor protection valve outlet to service brake chambers Inline placement between dual-circuit foot valve and rear-axle service chambers Long-line tractor and trailer service brake circuits where exhaust path is restricted Mounts directly to a tractor protection valve or inline in the service brake delivery line. Verify port orientation (supply vs delivery) and that no thread sealant is required on the male port.
