Sealco SC110139X Relay Valve

The Sealco SC110139X Relay Valve is a four-delivery-port service relay valve used in heavy‑duty air brake systems to feed brake chambers from the supply line while regulating control pressure to the actuators. It features four 3/8" delivery ports, a 3/8" control port, a 3/8" auxiliary supply port, and a 3/4" reservoir port, with a nominal crack pressure of 4.5 psi. Built from corrosion‑resistant aluminum (with brass components as applicable) and manufactured to Sealco’s OE specifications, this valve presents a 1:1 pressure relationship in normal operation and includes a ratio mode intended to enhance braking response in hard-stop scenarios. The SC110139X is a genuine Sealco part (often listed alongside 110139/110139X variants) and is commonly cataloged in Meritor and aftermarket networks under SEL110139 or BEN110139X. It is designed for reliable service in commercial vehicle braking systems and supports standard 3/8" lines for control and supply, a 3/4" line for reservoir sensing, and 4 x 3/8" outputs to brake actuators.