Description

Overview

The Sealco air brake tractor protection valve helps safeguard tractor brakes if a trailer breaks away or loses air supply in a heavy vehicle combination. It closes the trailer supply line automatically as system pressure falls, so the tractor retains braking capability. This compact valve suits standard dual-line air brake systems on prime movers and rigid trucks towing trailers.

Features

• Protects tractor service and emergency brakes during trailer breakaway or supply line failure.
• Automatically closes and vents the trailer supply between roughly 45psi and 20psi to limit air loss.
• 1/4in and 1/2in NPT ports suit common heavy vehicle air brake plumbing layouts.
• Compact body that can be mounted close to gladhand connections or frame rail plumbing for efficient hose routing.

Specifications and Materials

Supply and control inlets are 1/4in NPT, with supply and control outlets at 1/2in NPT to match standard trailer emergency line plumbing. The Sealco air brake tractor protection valve is a normally open breakaway valve that closes as emergency line pressure falls through the 45psi to 20psi range, helping isolate the tractor from a failed trailer circuit. Part number: AB8486. Further technical detail is available in the manufacturer technical datasheet

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. Cross-reference part numbers include RSL7700, TDARSL7700, S765147310, ESL7700.

Compliance and Safety

A suitably qualified heavy vehicle technician must install and test this valve, because incorrect plumbing can seriously reduce braking performance. After installation the system should be leak-tested, then the tractor protection function verified by simulating trailer breakaway and confirming the tractor retains full braking. Always depressurise the air system before removing or servicing any tractor protection valve, and follow relevant OEM and fleet procedures.

Trailer Applications

The Sealco air brake tractor protection valve is typically used on road tractors and rigid trucks towing semi-trailers, B-double sets and other multi-trailer combinations. It is suited to general freight, tanker, tipper and bulk haul applications where reliable isolation of a failed trailer circuit is critical. When in doubt, match port sizes and mounting layout to the existing valve and follow OEM diagrams.

Cross-reference and Suitability

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

Why Choose ICS Trailers

ICS Trailers focuses on heavy vehicle trailer parts, so you get proven brands, technical product data and support that understands workshop realities. Stock is selected to suit Australian conditions and common fleet specifications, helping you keep combinations compliant and productive with less downtime.
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