Description

Overview

The Wabco relay valve 4 port speeds up service brake response on heavy trailers and converter dollies. It repeats the control signal at the axle group, so the brakes receive a fast and even application. As a result, the combination stops more predictably, even when pipe runs are long.

Features

This Wabco relay valve 4 port uses two 3/4″ NPT supply ports to feed air from the reservoir. Additionally, four 3/8″ NPT delivery ports let you supply multiple axle groups or sides without extra manifolds. A 1/4″ NPT control port brings in the service signal from the brake valve. Furthermore, the compact body suits mounting close to the axles, which reduces line length and lag.

Specifications and Materials

Part number: AB8480P.

Wabco builds the relay valve body for typical trailer system pressures and standard dry, clean compressed air. It connects through 3/4″ NPT supply ports, 3/8″ NPT delivery ports and 1/4″ NPT control ports. In addition, the four delivery outlets give you flexibility when you lay out brake lines across the axles. For more detail on relay valve performance tests, see this relay valve test standard overview

Compatibility and Fitment

This cross-reference listing means this valve is a suitable replacement for the part numbers and applications shown. Some changes in air line plumbing may be required. 9730110060, 973 011 006 0, 973.011.006.0

Compliance and Safety

Correct installation of this relay valve supports compliance with heavy vehicle brake performance requirements. It must form part of a properly engineered system for the trailer or dolly. You should always follow the trailer or dolly manufacturer instructions and any relevant standards when you replace brake valves. Additionally, use suitable fittings and clean, dry air so you avoid internal contamination and leaks. After you fit the valve, perform a full leak test and a controlled road test to confirm even response across the combination. If you are unsure about plumbing or mounting, a qualified brake specialist should carry out the work.

Trailer Applications

The Wabco relay valve 4 port suits semi trailers, converter dollies and multi trailer road train combinations that need faster brake response. It usually mounts close to the axle group to shorten the distance between the valve and the service chambers. Consequently, it helps cut brake lag and keeps application pressure more even along long wheel base trailers. In addition, the four delivery ports simplify plumbing changes if you later adjust axle layouts or add lift axles.

Cross-reference and Suitability

This part cross-references to or suits the following equivalent part numbers and compatible alternatives:

Use this list to match existing documentation and confirm that the replacement valve aligns with the original build specification.

Why Choose ICS Trailers

ICS Trailers focuses on parts that suit Australian heavy trailer fleets and real on road conditions. You get selected air brake components, clear information and practical support from a team that understands workshop needs. Moreover, stocking compatible components across the air brake range lets you source valves, fittings and related hardware in one order. This approach can reduce downtime and freight costs for workshop and fleet customers. For more options, browse Air Brake Parts at ICS Trailers