Stay Safe and Dry with Semi-Truck Air Valves & Dryers

Keep your air brake system running smooth with reliable air valves and dryers for your semi truck. These components are essential to your rig’s safety, especially when it comes to braking performance and moisture control.

What Do Air Valves and Dryers Do?

Air valves control how air flows through your truck’s brake system—activating service brakes, parking brakes, and trailer brakes at the right time. Air dryers remove moisture and contaminants from the compressed air before it enters your braking system. Without a properly working dryer, moisture buildup can lead to rusted lines, frozen valves, or failed brakes—especially in cold or wet weather.

Why Replace Them?

- Over time, air dryers lose efficiency. - Filters clog. - Desiccant cartridges wear out. - Valves can develop internal leaks or sluggish response times. If you’re noticing slow brake response, air pressure drops, or water in your tanks—it's time to inspect and replace these parts.

Invest in Quality for the Long Haul

At 4 State Trucks, we carry high-quality aftermarket air dryers, purge valves, cartridge filters, and control valves that match OEM performance. These parts are built for the heavy-duty demands of commercial trucks and fleets. Most replacements are direct-fit and easy to install, so you can get back on the road fast with peace of mind.

Designed to Fit Your Model

Whether you drive a Peterbilt, Kenworth, Freightliner, or International, upgrading your air system with reliable components helps you avoid costly downtime. Our selection includes everything from complete air dryer assemblies to individual purge valves and filters—so you can replace just what you need. You can also buy air pressure gauge sensors for your dashboard, among other related accessories. Keep your system dry, your brakes responsive, and your truck compliant. Shop durable, road-tested air valves and dryers today.