303.01.0010.02 Relay Valve Repair Kit equivalent to WABCO

What does a relay valve repair kit do?

A relay valve repair kit is a diaphragm, O-ring, valve washer, and spring set designed to overhaul the relay valve that delivers fast, balanced air to the brake chambers in a heavy commercial vehicle's air brake system. The relay valve senses pilot air from the foot brake valve and redirects reservoir air straight to the chambers, significantly shortening brake response time.

Compatible vehicles and engines

This kit is designed to be used in vehicles such as Volvo F12, Volvo FL12, Ford Trucks Cargo series, and Volvo B12 engines. It is also fitted to Volvo N10, N12, and Volvo F7 trucks. The kit ensures high-strength component reliability during operation.

Installation and maintenance

To ensure proper installation, technicians should verify the axle position—whether front or rear—as diaphragm diameters and valve disc sizes vary by application. It is recommended to inspect all seals and springs during the overhaul to prevent air leaks or delayed braking response. Always check that the kit includes all necessary washers and O-rings before beginning service.

Troubleshooting and selection

Maintaining the pneumatic system with high-strength components helps prevent brake lag and uneven pressure distribution. Consult your authorized distributor for precise fitment guidance.

OE cross-reference

303.01.0010.02 (Relay Valve Repair Kit Relay Valves) is the equivalent of the WABCO OE numbers. This part directly replaces WABCO OE numbers 9730110000S2, 9730110010S2, 9730110050S2, 9730110110S2.