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The Importance of Air System Protectors

A truck brake system is an integral safety feature, so it is essential to take protective and preventative measures to properly maintain this system and increase its longevity.

What is an air system protector?

An air system protector or ASP is a type of compressed air system filter that prevents moisture, aerosols and oil particles from entering the air brake controls. These contaminants pose risks and will compromise the efficiency of your system if not properly managed.

ASPs have been commonly used as a protective measure for European truck brake components for around 20 years, and over the last decade as American trucks have moved towards disc brake systems with EBS controls. ASPs have also become common on Japanese trucks as they replace traditional hydraulic wedge brake systems with late generation air system controls and disc brakes.

How the WABCO Air system protector operates

Aerosol and moisture contamination affects the compression characteristics of air brakes, reducing the amount of force available for them to stop the truck efficiently.

Additionally, oil particles can cause damage to the air brake system of a truck, significantly shortening its lifespan and leading to costly consequences such as roadside failures, breakdowns and unplanned downtime.

During system pressure build-up, compressed air passes from the compressor into the WABCO air dryer. There, moisture-laden air passes through a desiccant bed within the air dryer cartridge and moisture is retained by the desiccant. In Wabco ASPs the compressed air then passes through a second stage coalescing filter to remove oil and other contaminants.

Features of the WABCO Air System Protector

· Eliminates moisture, aerosol and oil droplets

· Combines a coalescent filter layer at the bottom of the cartridge with conventional desiccant material

· Has a recommended lifespan of 2 years

· Throughout its recommended lifespan, it consistently maintains optimal performance


WABCO ASP Silver Cartridge and WABCO ASP plus Gold cartridge

WABCO ASP – Silver Cartridge

The Silver Cartridge Wabco ASP uses high-quality desiccant material to give it excellent drying performance and high mechanical reliability. It also includes a Coalescing Fleece Filter to remove oil aerosols. This item is used to improve the protection of the compressed air and braking system. You can find this cartridge with up to 13 Bar applications with M 39*1.5 and G 1 1\4” thread size.

WABCO ASP Plus – Gold Cartridge

The Gold Cartridge uses two desiccant materials which increase air dryer performance even further. It also features two Coalescing Fleece Filters before and after the desiccant, providing advanced oil particle removal and a 50% extended lifetime. This item is ideal for trucks that have high air consumption. Available up to 13 Bar applications with M39*1.5 thread size.

Avoiding counterfeit air dryer cartridges

Unfortunately, as WABCO air dryer cartridges are among the best around, copies have been made and are sold at several truck parts dealers. We were able to obtain some of these copies and test them against genuine WABCO parts. In every test, WABCO easily outperformed the non-genuine truck parts.

When lower quality air dryer cartridges are used, it exposes you to road safety risks and mechanical damage. The dryer is responsible for keeping the system completely moisture-free. If it malfunctions or has a lower technical performance, the brake system and air chamber or callipers will accumulate water vapour, leading to corrosion, rusting and reduced effectiveness.

Avoid this by using authentic WABCO aftermarket parts for trucks and buses, and ensure when purchasing parts, you always shop at authorised WABCO truck parts dealers.

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