Description

Overview

This trailer spring brake valve controls the parking and emergency brakes on heavy trailers that use spring brake chambers. It combines relay and pressure protection functions so the driver can apply and release the trailer brakes in a controlled way. As a result, it helps maintain air supply integrity while still giving positive braking response. This Pacific market version suits common trailer configurations in local fleets.

Features

The valve uses separate supply and delivery circuits to manage service and spring brake functions with graduated control. It delivers quick application and release to the spring brake actuators so the trailer responds closely to the foot valve. Additionally, the design helps protect the trailer air system by closing off flow if pressure drops below a safe level. In practice, this supports stable braking performance in mixed prime mover and trailer combinations.

Specifications and Materials

This valve is configured as a trailer spring brake relay valve with integrated pressure protection. It operates in a dual-circuit air brake system so primary and secondary circuits retain separation. Typical porting includes a reservoir port, delivery ports to the spring brake chambers, and service ports for the control signal from the service relay. Supply and service ports are usually 1/4-18 NPT, delivery ports 3/8-18 NPT, and the reservoir port 1/2-14 NPT, which suits standard heavy trailer plumbing. Part number: AB8422P. For more detail on trailer spring brake valve operation, refer to this manufacturer technical guide for trailer spring brake valves.

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. 109539, 065549, 109620, 109615, 065437, 65437, 102831, ABC109539, SR-5

Compliance and Safety

When you install this trailer spring brake valve, you should follow recognised heavy vehicle air brake practices and the trailer manufacturer’s drawings. All joints must be clean, correctly sealed, and tightened to avoid leaks that could reduce available brake force. In addition, you should carry out leak testing and full brake performance checks after installation or replacement. Regular inspections help confirm that the valve continues to operate smoothly and that the trailer brakes apply and release evenly across all axles.

Trailer Applications

This valve suits heavy trailers that use spring brake actuators for parking and emergency braking in two-line or three-line trailer systems. It works in combination with the towing vehicle’s control valves so the driver can set and release the trailer parking brakes from the cab. Moreover, it is well suited to multi-axle semi-trailers and similar combinations that rely on stable spring brake control under varying load and road conditions. Fleet use on local Pacific specification trailers benefits from the familiar layout and porting pattern.

Cross-reference and Suitability

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

These cross-references help you match an existing trailer spring brake valve by its stamped or catalogued number when selecting a replacement.

Why Choose ICS Trailers

ICS Trailers focuses on heavy trailer parts, so you can match this trailer spring brake valve with the rest of your air brake components confidently. The team understands common Australian trailer brake layouts and can assist with part identification when existing markings are hard to read. In addition, stocking dedicated air brake parts helps reduce downtime when a valve fails in service. For more trailer brake options, Browse Air Brake Parts at ICS Trailers today.