ABS Trailer Modulator Relay Valve Assy For Wabco 4721950330 Meritor S4721950330

ABS Trailer Modulator Relay Valve Assembly for Wabco, Meritor

This ABS trailer modulator relay valve assembly controls air delivery to trailer brake chambers and directly replaces Wabco 4721950330 and Meritor S4721950330 units.

Overview

This ABS trailer modulator relay valve assembly is a critical component in trailer air brake systems, precisely regulating air pressure during ABS events. It replaces Wabco 4721950330 and Meritor S4721950330 valves, restoring full anti-lock braking function. The ABS trailer modulator relay valve assembly ensures consistent braking performance for commercial trailers and heavy-duty fleets.

Built For Performance

• Fast-response solenoid valve enhances ABS cycling for shorter stopping distances
• Robust die-cast aluminum body resists corrosion from road salt and moisture
• Integral relay function provides quick service brake application without delay
• Drop-in design matches original mounting and port locations for easy replacement
• Tested to OEM pressure and cycle specifications for reliable long-term operation
• Compatible with standard 12V/24V trailer ABS electronic control units

On-The-Job Use

• Replacing a faulty modulator valve to restore ABS function on single, tandem, or tri-axle trailers
• Used during preventive maintenance of air brake systems on dry vans, reefers, and flatbeds
• Servicing ABS-equipped tankers and construction trailers that require precise braking control
• Upgrading older trailer ABS setups to a known cross-reference valve

Specs At A Glance

Good To Know

Q: Will this valve work with both Wabco and Meritor ABS systems? A: Yes, it is a direct replacement for the Wabco 4721950330 and Meritor S4721950330 valves, fitting standard trailer air brake configurations without modification.

Q: Do I need to recalibrate the ABS after installing a new modulator relay valve? A: In most cases, the trailer ABS self-calibrates after a few brake applications; however, on some systems a manual re-learn procedure may be required so consult the manufacturer’s guidelines.

Slight variation in finish or dimensions may occur between production runs, and fit can depend on serial number, so confirm compatibility before ordering.