Draining water from air tanks was part of a truck or bus driver’s daily routine. Many companies now rely on air dryers to handle that job — absorbing moisture and protecting your system’s components.
But here’s the thing: if you notice water draining from the purge valve, it could be a sign your air dryer needs replacing.
A small amount of oil discharge passing through the purge valve is normal during regular operation. However, when oil mixes with water vapor, it creates a sticky mess that can:
- Disrupt air discharge cycles
- Block the purge valve, causing constant leaks
- Coat the air dryer media, reducing its effectiveness
- Build-up in air lines and valves, shortening system life
Many common problems with the air braking system can be managed with regular maintenance.
While a little discharge is expected, too much is a warning sign you shouldn’t ignore.
Many common problems with the air braking system can be managed with regular maintenance.
The top reasons to routinely replace your air dryer:
Prevent Brake Failure
In heavy-duty road trucks and buses, compressed air actuates the braking systems on the primary vehicle and any towed trailers.
The problem? Air pulled from the atmosphere contains moisture. When air is compressed, condensate forms. If that moisture isn’t removed, it can:
- Lead to ice formation in the lines
- Corrode critical brake components
- Cause total brake system failure
- Shorten the lifespan of your valves and other components
An effective air dryer ensures braking systems are supplied with dry air, even under tough conditions.
Extend the Life of Your Entire System
Contaminated air doesn’t just harm individual parts — it strains your entire air system.
Extra load and airflow restrictions can lead to bigger problems over time.
Stay ahead of issues by checking:
- That the air dryer canister is undamaged and secure
- All hoses should be checked for kinks, bends, or leaks that could restrict airflow
- That the purge valve is working properly (a stuck valve can slow pressure build-up and impact performance)
Choose the Right Protection
Donaldson coalescing air dryers are built to meet the needs of today’s advanced systems — removing oil, moisture, and contaminants to protect your brakes, your entire air system and your safety.
Stay proactive.
Maintain your air system and replace the air dryer as needed to keep your fleet running.
