Used Truck Air Dryers & Air Processing Units

Used truck air dryers & air processing units

In a modern heavy truck, the air dryer is a key part of the air brake system. After the compressor builds pressure, the air passes through a desiccant cartridge inside the dryer, which removes moisture and often oil and solid contaminants before the air enters the reservoirs. This helps prevent corrosion, blocked lines and freezing in cold weather, and protects valves, brake chambers and other components throughout the system.

In this category we list used OEM truck air dryers and air processing units removed from late-model European lorries. Current examples include WABCO ECAM air dryers for MAN TGX/TGS Euro 6, Knorr-Bremse APU/ELA1000 air dryers for DAF XF106/CF, an air dryer bracket with valves for Volvo FH4/FM4 Euro 6, and a Mercedes Actros MP4 EAC air dryer unit. Each item is photographed from multiple angles and listed with genuine OE numbers so you can match it to your vehicle.

What you will find in the Air Dryers category

Stock in the Air Dryers category changes as we dismantle more trucks, but it typically includes:

• complete air dryer assemblies (ECAM, EAC, APU and similar air processing units) for disc brake systems;
• air dryers with integrated multi-circuit protection valves and pressure control functions;
• air dryer brackets and mounting frames with attached valves and pipework, especially for Volvo FH/FM;
• units from OEM suppliers such as WABCO and Knorr-Bremse, used as original equipment on MAN, DAF, Volvo and Mercedes trucks;
• selected air dryer components (for example, brackets or valve blocks) when removed separately.

Each product listing shows OE or OEM part numbers, brand markings and electrical/air connections so you can compare them with your existing unit.

Truck brands & typical applications

Most air dryers and air processing units in this section come from mainstream European trucks, including:

• MAN TGX / TGS Euro 6 tractors and rigids;
• DAF XF106 and CF Euro 6 models;
• Volvo FH4 / FM4 Euro 6;
• Mercedes-Benz Actros MP4 and related platform vehicles.

These air dryers are designed to work with OEM brake and suspension systems, often in combination with specific compressors, air tanks and electronic control modules from WABCO, Knorr-Bremse and other approved suppliers.

How truck air dryers work in the air brake system

On a typical air brake system, the engine-driven compressor draws in ambient air, compresses it and sends it towards the reservoirs. Before the air reaches the tanks, it passes through the air dryer:

• moisture-laden air enters the dryer body from the compressor;
• inside, a desiccant cartridge absorbs moisture and may also trap oil mist and particles;
• clean, dry air then flows out to the air tanks and brake circuits;
• during the purge cycle, the dryer automatically regenerates the desiccant by venting moisture and contaminants to atmosphere.

By ensuring that only dry, filtered air enters the reservoirs, the air dryer helps prevent internal corrosion, frozen lines and sticking valves, especially in cold and wet climates. This is essential for reliable braking performance and long service life of expensive pneumatic components.

How to choose the correct air dryer or air processing unit

To avoid ordering the wrong air dryer for your truck, always check:

• OEM part number on the existing air dryer or air processing unit (for example MAN, DAF, Volvo or Mercedes OE numbers plus WABCO or Knorr-Bremse references);
• supplier brand and model – ECAM, EAC, APU/ELA1000 or other specific air dryer type;
• truck brand, model, year and Euro class (for example MAN TGX Euro 6, DAF XF106, Volvo FH4, Actros MP4);
• mounting style – bracket layout, bolt pattern and orientation on the chassis or frame;
• port threads & layout – number and position of air connections, thread size (for example M22 x 1.5) and any integrated multi-circuit protection valves;
• electrical details – 12V or 24V heater, plug type and any additional sensors or control wiring;
• any specific system options on your truck (ABS, EBS, air suspension) that may require a matching air processing unit.

If you are not sure which air dryer you need, you can contact us with your VIN or registration number and clear photos of the existing unit, including its labels. Our team can help you cross-check part numbers and identify a suitable replacement. For general advice, see How to Find the Right Part and Compatibility & VIN Policy.

Tested used OEM air dryers from dismantled trucks

Where possible, we run and check donor vehicles before dismantling to confirm that the air system builds and holds pressure correctly. During removal, our technicians inspect each air dryer and bracket for obvious damage, broken connectors, cracked housings and heavy corrosion. Units that do not meet our standards are rejected; only good used parts are cleaned, labelled and stored under cover in our warehouse.

Because we specialise in used OEM truck parts, you benefit from:

• air dryers designed specifically for heavy-duty commercial vehicle brake systems;
• correct interfaces to your existing compressor, air tanks and control valves;
• honest condition descriptions and detailed photos of the actual unit you will receive.

You can learn more about how we source and check parts on our Our Dismantling & Quality Process and Warranty & Part Condition pages.

Related brake & air system categories

If you are rebuilding or troubleshooting a larger part of the air brake system, you may also want to browse:

• Air Compressors – engine-driven compressors and related air supply components;
• Air Tanks – reservoirs that store compressed air from the dryer;
• Brake Chambers – actuators that turn air pressure into braking force at the wheels;
• Brake Lines, Hoses & Fittings – the pipework and hoses that distribute air through the system;
• Other Brake Parts – additional valves, sensors and components for air brake systems.

Delivery, payment & returns

All air dryers and brake parts are shipped quickly from our UK warehouse with tracked delivery options available across the UK and EU. For details about shipping methods, transit times and costs, please see our Delivery & Shipping page.

Information about payment options, VAT and our returns policy is available on Payment & VAT and Returns & Refunds. If you need help building a complete order for multiple air system components on the same truck, please contact us – our team will be happy to assist.