According to the hose experts at Phillips Industries, cold weather can create problems with tractor-trailer air system freeze-ups. To help prevent this, they recommend that the air brake system be checked regularly for excessive leakage and that reservoirs are constantly drained. Air dryers also should be inspected to make sure they are functioning properly, as well.
Check the air brake system for excessive leakage because it can cause the compressor to pump more air and moisture into the brake system—and more moisture means an increased chance for freeze-ups.
For air systems without an air dryer, routinely draining the air system helps reduce the possibility of freeze-ups. All reservoirs in a system can accumulate water and contaminates, which must be drained—this should be done daily. During winter, it may be beneficial to drain the system more than once daily.
There are two methods to drain the reservoirs:
1. Shut off the engine and then drain all the air from each reservoir
2. Open all the drain cocks on all the reservoirs and leave them open over-night to drain all contamination.
Automatic drain valves installed on a truck eliminate the need for daily reservoir draining; however, their function should be checked before the winter weather sets in. Even though automatic drain valves may be in place, manual draining of the lines is still required periodically.
For those air systems with an air dryer, it is very important that the dryer functions properly to ensure the air system in running clean and dry. To help maintain proper operation, make sure to change the desiccant cartridge and purge the valve as necessary. Other preventative measures include:
• Use dummy hose couplings on the tractor and trailer.
• To avoid water traps within the hose check for drooping lines.
• If the lines do become frozen, thaw them.
Thawing lines:
The only way to thaw the lines without causing damage to the air system is to park the vehicle in a warm building. Once the lines have been thawed, only remove the vehicle back into the outdoors when it is ready to go into operation again. Parking the vehicle outside immediately after thawing the air system can cause condensation, which will re-freeze the system.
DO NOT apply an open flame to the air lines or valves. Not only can this damage the valves and melt the air lines, but it also is dangerous and can cause a fire.
DO NOT pour fluids into the air lines or gladhands. This can cause damage to the rubber components. It also can wash lubricants out of valves. Without lubricant, valves will not operate properly, causing accelerated wear, which leads to premature replacement. Liquid also can collect in the brake chamber and valves and cause malfunction.
For more information, visit www.phillipsqwiktechtips.com.
