What Are Gladhands?

by Pride Transport | Mar 21, 2024

Gladhands, also known as gladhand air hose connectors or couplers, are a type of interlocking hose coupling. They are used to connect pressurized air hoses and brake lines between your truck and trailer. 


Understanding what each color of a trailer gladhand does and what it’s used for is essential for maintaining your vehicle. Making a mistake when hooking these couplings up could lead to serious problems with your brakes and a potential collision on the road. 


Gladhand Definition

Long ago, the term “glad handing” was coined to describe shaking or clasping hands warmly when meeting someone (and, in politics, doing so with an ulterior motive). In the commercial trucking industry, the gladhand definition is different. Gladhands are coupling devices that connect your truck’s service and supply lines of air to your trailer. The exception to this rule is the “green gladhand,” which is an electrical line. 


How did simple couplers get to be called gladhands? There is no clear history describing who came up with the name for these truck couplings, but the reasoning is simple: To connect gladhands, you place their rubber seals together at a 90-degree angle before snapping them downward to lock them into place. That handshake-like movement is what led to their name. 


Interestingly, gladhands are not only essential to keeping your vehicle braking safely — they’re also a symbol of connection and communication in trucking.

What Do Gladhands Do?

Gladhands are couplers located between the back of the truck and front of the trailer. Generally, they’re used to connect air hoses between the tractor and trailer. Green gladhands are an exception and contain electrical wiring.


Other gladhands ensure proper airflow for pneumatic braking systems. That’s an important job, too, with significant risks if airflow doesn’t continue as needed. 


If the wrong colors are crossed accidentally, the supply air will go into the service line. As a result, there will be no air to charge trailer air tanks, and the trailer spring brakes (also known as parking brakes) won’t be able to release. In some older trailers, there are no spring brakes. In that case, crossing lines could cut the air to your trailer brakes, creating an extremely dangerous situation for you and anyone else on the road. 

pride transport employee checking truck

The Color Code for Gladhands

Commercial vehicles have gladhands of different colors, which helps prevent them from getting crossed. You’ll have blue, red, green, and/or black gladhands on your vehicle. Each one has its own purpose.


  • Black gladhands are interchangeable, and they’re known as universal couplers. 
  • Red gladhands connect your emergency brake airlines between your truck and trailer.
  • Blue gladhands are service gladhands. They connect service air lines between your truck and trailer. They deliver air to trailer hand or foot brakes. 
  • Green gladhands are electrical lines.


You may also see other colors of gladhands, such as yellow or white, though they’re less common. 

pride transport employee working on truck

Maintenance of Gladhands

Gladhand maintenance is an essential part of keeping your air brakes working correctly. Neglecting them could lead to the contamination of the air brake with moisture and debris or completely prevent air from being available when it’s needed. 


Some common issues with gladhands include leaky seals and damage to their aluminum bodies. 

  • Leaky seals made with rubber can easily be replaced and are inexpensive parts.
  • Using anodized gladhands can help prevent corrosion, but the powder coating may fail. Corrosion can cause damage to air lines and contaminate them, so replacing the faulty gladhand is essential. 


You should also watch out for grooves in your connector and detent plates. When they become worn, coupling will become more difficult (or even impossible). Replace them if you notice signs of corrosion or wear and tear.


Here are some additional tips to ensure gladhands work as intended:

  • Check gladhand seals regularly. If there are cracks or signs of damage, it’s a good idea to replace them. Gladhands should be replaced annually, with your air lines, or when you notice damage or corrosion. 
  • Keep gladhands in their stowage when you drop a trailer. Doing this helps prevent moisture and debris from getting into the air lines. 
  • Feel for tension. If there is a lack of tension when you couple or uncouple gladhands, there may be a poor seal. You can replace the seal if it’s damaged. 


As for troubleshooting, if the gladhands look like they’re in good condition but you’re still having problems connecting them, start with the color coding. Ensure the correct colors are lined up. 


If lining up the correct colors doesn’t help, look at the tabs on the gladhands to ensure they’re in the appropriate locations before attaching them. If so, and if they still won’t connect, you may need to replace the seals or gladhands to get a tight connection.

Safety Considerations With Gladhands

It is always important to keep an eye on your truck’s gladhands and to repair or replace them when they show signs of wear or damage. 


During your pre-trip inspection, look over your gladhands and their seals. Do they look to be in good condition? If not, you may need to replace them before making the trip.


If they do look fine, it’s time to connect them. To attach your gladhands, you’ll simply line up the parts and rotate down gently. It’s a good idea to wear gloves when you do this, so you can prevent accidental pinching.

Innovations and Advancements in Gladhand Technology

While gladhands are straightforward connectors, there’s always room for improvement. 


Here are a few changes in gladhand technology you might be interested in:

  1. Phillips Connect SmartLock Gladhand. This technology can identify if a unit needs repaired. As a part of a smart trailer, it also ensures only authorized users can gain access (doing this prevents theft). 
  2. AI coupling systems. ISEE, an AI company, has released a fully automated, AI-powered trailer auto-coupling system
  3. Quick-connect couplers. Quick-connect couplers go on fast and may have increased air brake response times.


Although gladhands may seem like minor parts of a truck, they are an essential part of staying safe and keeping your brakes working properly. New gladhand technology aims to help you stay on the road and complete your routes as safely and securely as possible. 

Drive With Pride

Gladhands have a long history of connecting trucks, trailers, drivers, and our industry.

At Pride Transport, we love connecting to people in our community and are excited to welcome new drivers to our family. Apply now and see what makes us better.

pride transport truck driver smiling in drivers seat

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