Description

Overview

This QR-L quick release valve 1/2in gives trailer air brake systems fast, local exhaust so brakes can release cleanly after each stop. It mounts inline near the brake chambers and therefore shortens the path that air travels when the driver lets off the pedal. As a result, the valve helps reduce drag, heat, and uneven lining wear on heavy trailers.

Features

• Inline quick release valve layout for direct mounting in the service line close to the brake chambers
• 1/2in NPT supply and 1/2in NPT delivery ports that suit common heavy trailer plumbing
• Fast exhaust path that helps brakes release quickly and limit brake drag after an application
• Compact body that fits most existing QR-L quick release valve locations on trailers and dollies

Specifications and Materials

This QR-L quick release valve 1/2in arrangement uses a single 1/2in NPT supply port and twin 1/2in NPT delivery ports to suit typical service line layouts. The internal mechanism seals the exhaust while the driver applies the brakes, then opens a direct exhaust path as pedal pressure comes off. Consequently, air vents at the valve instead of travelling back through the treadle valve, which can improve release times on long trailer combinations.

Part number: AB8448P.

For deeper background on how quick release valves work in air brake systems, review this manufacturer-style quick release valve technical guide which explains typical construction and operation.

Compatibility and Fitment

This QR-L quick release valve 1/2in layout suits service brake circuits that need faster exhaust and more consistent release, especially on multi-axle trailers. Installers should match the 1/2in NPT supply and delivery ports, confirm line routing, and check mounting clearances against the original valve before final fitment. In addition, they should verify that the valve position still allows easy access for inspection and replacement.

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. 065707, 131025, 5003395, 65707, 401145, 032019, 5003391, 5003394, K800333, PQV-5222, 195165, QR-L, QRL.

Compliance and Safety

Quick release valves play a critical role in maintaining compliant and predictable air brake performance, so a suitably experienced technician should always carry out the installation. After fitting this QR-L quick release valve 1/2in unit, the technician should perform a full leak test, confirm correct service and release behaviour, and check that brake timing stays within the vehicle manufacturer guidelines. Furthermore, regular inspection of airlines, tanks, and filters helps limit moisture and contamination that can shorten valve life.

Trailer Applications

This type of inline quick release air brake valve commonly works on semi-trailers, dog trailers, converter dollies, and other heavy combinations with long service lines. By exhausting air close to the chambers, it can reduce release lag between axles and improve overall brake feel. For example, fleets that run general freight, tippers, or tankers with 1/2in NPT plumbing can use this pattern as a service replacement for many QR-L style valves. Finally, it suits both new builds and repair work where the original mounting location already exists.

Cross-reference and Suitability

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

Always compare the original valve’s function, plumbing, and mounting position to this QR-L layout before signing off on the replacement in a trailer air brake system.

Why Choose ICS Trailers

ICS Trailers focuses on proven air brake components for heavy trailers, backed by practical experience with working fleets. Our team helps match valves to existing hardware and cross-reference lists so workshops can source replacements with confidence. Moreover, we keep a broad range of trailer brake parts on hand to reduce downtime when you need to get equipment back on the road.

For related fittings and valves, browse Air Brake Parts at ICS Trailers