How to tell if/when the airbag suspension on the truck has a leak

If an air bag is leaking, it's a non stop hissing sound. When you park, you will lose almost all of your air pressure. It's normal to hear some leaking when you park. They deflate some once you let the air out. If you're idling and you hear the non stop sound get it changed asap. You don't want it to blow on the side of the road

 

Hmmm. What does your air pressure gauge read when you crank your truck up in the morning?

 

If you feel uncomfortable with it, get your company to change it. If they won't do it at the terminal, go to the TA and make the spend the money...make it seem like it's all the way blown

 

A slow air leak, is very hard to hear unless in absolute quite conditions. For shops to find them, they usually have to use a spray bottle with soapy water. If in the suspension system you will probably notice a faster loss of air when heavy, then when empty or light. If it's not isolated to the suspension system, then it will probably leak at the same rate, no matter. Some leaks increase leakage rate with colder temps. If it takes 10+ hours to lose 15-25 pounds of air, I would not worry about it until you get to the shop, then tell them.

Critical leaks (while parked) that might get you in trouble at an inspection can usually be heard if it's somewhat quiet. But remember to check for leaks during brake application and when the red button is pressed in. Use something to hold down the trailer brake handle [while the red button is pressed in] then go back and listen for leaks.

 

Get a spray bottle of soapy water. Spritz the air bags, any leak will blow bubbles and prove your theory.

However if it is a minor leak (less than 10lbs an hour) probably not going to fix it until it gets worse.

 

There is a leveling valve under there that will dump air to try and level out the suspension, especially while the trailer is being loaded or unloaded, or if you park on unlevel ground. However, I don't think the air bags themselves should ever leak air, just the leveling valve.

 

Sometimes on older trucks the bead around the edge of the airbag gets worn down and slowly leaks out around the bezel when under pressure and the bags need to be replaced. Most places are too cheap to do it when it should be done.

Just hope you aren't standing next to an airbag if it blows. I was standing next to the tandems of a trailer last year when a bag blew out, and my ears were ringing for weeks.