Air bags look squished in the morning.

Ya, STexan. My truck has 1,038,750 miles and 7 years on the roads, and surely has accessory problems. The brake system is good so far.

I took the truck to Dr. House (Stewart and Stevenson, ABQ) and their tech found one issue. I'm better than that, so I'm just going patiently dealing with it. More or less, depending on the day. I figure, on a good day, that at least they're clustering around one timeframe.

 

Caution 409 will eat plastic and rubber it does desolve grease"oil based products"

 

Do I understand this correctly: You are concerned that your air bags look empty after the tractor has been sitting all night? Especially if it has been loaded? That is the question?

If the tractor has not been running, the compressor cannot generate any air to fill the air bags. If a a trailer is loaded, the additional weight cannot be offset with the leveling valve without the engine running. The air tanks don't have even close to enough volume to do that.

Even not loaded, if you leaked the maximum dot standard of 4psi a minute over the course of 10 hours: 10hours x 60minutes x 4psi = 2400psi. 2400psi is legal to leak over 10 hours in system that is only designed to hold 120psi. And of that 120psi the air suspension system is cut off when at least 45psi is reached.

The point is your overnight deflation is common and almost every truck will squat under those conditions. I have driven plenty of new trucks and small inaudible leaks are common in all trucks.

Loading with the engine off will result in the same condition no matter the length of time.

 

My Volvo always deflates it's suspension overnight. From day one with 35 miles on the odometer.

 

No matter what, keep asking questions. I still have a lot to learn after over a decade and everyone's input helps me as well. Hardly any of us started out as mechanics.

 

A few years before I retired I had an issue with my tractors air ride. Every time I shut down for a 10 the bags were down when I did my pre-trip. I finally discovered the reason one night while parked bobtail. I was in a quiet area alone and was outside listening in the quiet. I heard a very faint air leak in one the bags itself. The next day I told my company and they sent me to a shop in Richmond to get the bag replaced. Sometimes you have to be very quiet to hear those air leaks.

 

Windy conditions will help deflate your air bags too. The rocking motion can work a leveling valve pretty good. More prevalent with empty trailers though. Or bobtail.

 

Yep.

ANYTHING that rocks the trailer hard...

 

The tire guys use soapy water to find leaks. That would do the trick. Plus...bubbles makes it a party.