Air Brake Maintenance


Avoid Frozen Air Brakes This Winter

With the cold weather here, it is time to eliminate the possibility of frozen air brakes. These steps will ensure that air brakes perform as intended during the winter months and beyond.

An often overlooked part of daily vehicle maintenance is draining the water from the air brake system. Removing the water, rust, and other contaminants reduces the possibility of freeze up in the winter and protects the air brake system from general corrosion.


Harmful Elements

The air compressor, positioned inside the engine compartment, pulls air from the atmosphere. In the winter this air can contain corrosion causing de-icing agents. These de-icing chemicals are necessary to keep the roadways safe, but can be very harmful to the air brake system. Along with the corrosive elements water vapor and oil vapor sneak past the best air dryer to rest as watery, sludgy mess in a vehicle’s supply tank, also known as a wet tank.


In frigid conditions a build up of water in the wet tank will lead to freeze up. When a truck’s air brake system is frozen it can’t move; if the truck can’t move, it can’t do its job. Waste hauling vehicles tend to use a lot of air as the driver applies the brakes frequently thought the day. The more air that is compressed, the more water lands in the wet tank leading to a freeze up event. In some cases trucks have frozen up while on the route, which is a worst case scenario requiring a road call. A truck with frozen air brakes in the lot is not much better, but at least there is no road call.


Keeping Your Vehicle on the Road

The prevention of frozen air brakes is critical to waste haulers looking to keep their vehicles on the road this winter. Along with proper air dryer maintenance practices such as changing the air dryer cartridge once a year, there are ways to keep air brake systems ice free this winter—daily manual draining of the system, an alcohol evaporator or an automatic drain valve. There are pros and cons with each method:

  1. Daily Manual Draining requires the driver to use the manual drain to release the water from the wet tank. This method is affordable, but is an often overlooked aspect of the daily operation of the vehicle.
  2. Alcohol Evaporator method uses alcohol to keep the water from freezing in the air brake system. This is a time-tested solution, but the alcohol can be very hard on the component parts of the air brake system resulting in premature failure. Also, this requires maintaining another part of the vehicle.
  3. Automatic Drain Valves eliminate the need for manual draining and alcohol solution. The valve does all the work, which means the driver has one less task to complete. The price of the part can be an issue.


Maintenance During the Winter Months and Beyond

In order to be on the road during the coldest of conditions a program must be put in place and adhered to. Frozen air brakes can be eliminated by making sure the air dryer is working properly by checking for excess water in the air brake system and there is no water in the system. The system should be drained of water on a daily basis by either manually draining the system or using an automatic drain valve. Under-performing air brakes or freeze up events are sure signs that water is causing problems in the air brake system. With the cold weather here, it is time to eliminate the possibility of frozen air brakes. These steps will ensure that air brakes perform as intended during the winter months and beyond.


Erik Johnson is Marketing Manager for Expello Air Products. He can be reached at or visit


Case Study: St. Paul, MN Division, Large National Waste Hauler

A large national waste hauler with a fleet of vehicles dedicated to daily pick up of waste and recycling for residential and business customers had a division located in St. Paul, MN with a fleet of 100 vehicles to serve their customers.


When a waste hauling vehicle was on its route, the driver was applying the brakes at regular intervals. These brake applications caused the air system’s compressor to run frequently throughout the day. Each time the compressor ran, moisture was created and collected in the service tanks of the vehicle. In winter 2014, newer trucks were experiencing freeze up in line before the air dryer, multiple trucks could be down at the same time resulting in delayed service and overtime, the shop was estimating the cost of the freeze up event to be $80 to $270 minimum if it occurred in the yards.


The hauling company turned to Expello Air Products and their Expello Automatic Drain Valve (ADV), which removed moisture, oil and other contaminants from the compressed air systems every five minutes of the vehicle on time. It was easy to install and included a thermostatically controlled heater, durable construction that was maintenance free and featured a regular 5 minute purge cycle.


Prior to the installation of the Expello valve, a steady flow of moisture was observed when manually draining the wet tank. After adding the Expello valve, no moisture was present when draining the tanks. The pilot program completely eliminated freeze up events for vehicles outfitted with an Expello drain valve. Due to the pilot program’s success, the company began to outfit the fleet with Expello Automatic Drain Valves.