4324130060 | Genuine Wabco® System Saver 1200E Air Dryer 12V

Part number is a direct OEM component and replacement air dryer for Class 7 and Class 8 commercial vehicles:

• Freightliner Trucks: Cascadia, Columbia, Century Class, Business Class M2 106 / 112.

• Kenworth & Peterbilt: Kenworth T680, T800, W900; Peterbilt 579, 389, 379.

• International / Navistar: ProStar, LT Series, WorkStar, 4300 / 4400 / 7400 series.

• Volvo & Mack Trucks: Volvo VNL, VNM series; Mack CXU, Anthem, Granite.

• Buses & Commercial Vehicles: Transit buses, motorcoaches, and heavy vocational trucks using a 12V system setup.

1. What is it?

Part is an inline air dryer assembly installed between the engine-driven air compressor and the vehicle’s primary air supply tanks. It purifies compressed air by extracting water vapor, oil aerosols, and particulates before they reach critical air brake valves, ABS modulators, and pneumatic suspension components.

2. Core Functions & Technical Features

• Desiccant & Coalescing Filtration: Uses a spin-on cartridge packed with desiccant beads to absorb water vapor and capture microscopic oil particles.

• Regenerative Purge Cycle: Utilizes dry air stored in an internal or external purge volume to backflush trapped moisture out through the exhaust port during the compressor's unloading cycle.

• 12V Integrated Heating Element: Features an internal 12-volt heater managed via a Metri-Pack connector that prevents the purge valve and exhaust port from freezing during sub-zero operations.

• 11-Bar Safety Valve: Built to North American OEM standards with an integrated 11-bar (160 PSI) pressure safety relief valve to safeguard against system over-pressurization.

• Standard Port Sizes: Fitted with a 1/2"-14 NPTF supply/delivery port and a 1/4"-18 NPTF control port for seamless fitment into standard air lines.

1. Water or Oil Draining from Wet Tanks

• Symptom: Liquid water, sludge, or heavy oil accumulation drains out when manually opening the pull-cord valves on the primary/secondary air tanks.

• Cause: Saturated desiccant material, a expired coalescing cartridge, or internal oil bypass from a worn air compressor.

2. Freeze-Ups and Air Line Blockages in Cold Weather

• Symptom: Air pressure fails to build or brake valves freeze up in sub-zero temperatures.

• Cause: Failure of the integrated 12V heating element (or faulty Metri-Pack connector wiring), allowing accumulated moisture to freeze in the purge valve and exhaust port.

3. Continuous Air Leaking from Purge Exhaust Valve

• Symptom: Constant, loud air rushing out of the exhaust port at the bottom of the dryer while the compressor is actively pumping.

• Cause: A stuck-open purge valve piston, damaged O-rings, or a torn internal diaphragm inside the lower valve housing.

4. Slow Air Pressure Build-Up or Rapid Cycling

• Symptom: The vehicle's air gauge rises very slowly, or the dryer produces rapid, repeated "purging" noises (rapid cycling every few seconds).

• Cause: Clogged internal check valves, restricted desiccant cartridge flow, or a leaking governor signal line.

5. Safety Relief Valve Popping / Blowing Off

• Symptom: The 11-bar (160 PSI) integrated safety relief valve repeatedly pops open and exhausts high-pressure air with a loud bang.

• Cause: Internal blockage in the dryer body preventing air from flowing into the primary reservoir, or a malfunctioning governor failing to cut off compressor pressure.