What's in a straight air brake system
A straight air trailer brake system delivers compressed air from the tractor to the brakes at each axle. The core air brake parts include:
- Air hose and tubing — the lines that carry air to the brakes.
- Gladhands and air hose fittings for leak-free connections throughout the system.
- Relay valves — deliver air quickly and evenly to the brake chambers.
- Air tanks — store the compressed-air reserve for the trailer.
- Boosters — for air-over-hydraulic systems that use the truck's air to power hydraulic brakes.
Straight air ABS trailer brake kits
Trailers with air brakes built since March 1, 1998 are required to have anti-lock brakes. Our TA-7000 and TA-8000 series straight air ABS kits come in 2S/1M (two sensors, one modulator) and 4S/2M (four sensors, two modulators) configurations, including triple-axle versions.
Straight air or air-over-hydraulic?
Not sure which system you need? Straight air runs compressed air all the way to the brakes; air-over-hydraulic uses trailer air to actuate hydraulic brakes. If you're running hydraulic drum or disc brakes, see our air-over-hydraulic brake kits — available with ABS or without ABS. Learn more in Air-Over-Hydraulic Brakes Explained.
Need help spec'ing a system? Browse our spec sheets or contact us for custom and bulk orders. Orders placed by 2 PM ET Monday through Friday typically ship the same day, with free shipping on orders of $250 or more.
Frequently asked questions
What parts make up a trailer air brake system?
Gladhands, air hose and tubing, an air tank, a relay valve, brake chambers with slack adjusters, and an ABS system. Bludot Manufacturing makes the hoses, tubing, gladhands, tanks, relay valves and complete straight air ABS kits.
What's the difference between 2S/1M and 4S/2M ABS kits?
2S/1M uses two wheel speed sensors and one modulator that controls both sides of the trailer together. 4S/2M uses four sensors and two modulators, so it controls each side separately.
Do trailers with air brakes need ABS?
Yes. Trailers with air brakes built since March 1, 1998 are required to have anti-lock brakes.
Should I use straight air or air-over-hydraulic brakes?
If the trailer has hydraulic brakes and the truck has air brakes, air-over-hydraulic is usually the simpler option. Straight air is the standard for heavy commercial trailers built for air brakes at every wheel.
How fast do air brake parts ship?
Orders placed by 2 PM ET Monday through Friday typically ship the same day, and standard U.S. shipping usually takes 3 to 5 business days. Shipping is free on orders of $250 or more.