Reasonable time for air tanks to leak

In my time we used to open the tanks at quitting time, both the wet and dry. Leave them open overnight until morning. Close em up and get going to the new work day.

The real test is building pressure in your primary and secondary and then not dropping more than a smidge if at all and another test to be sure the red warning low air alarm goes on somewhere at 60 PSI and followed by the tractor protection valve at some point below 25 PSI. (Mr. POP!)

 

Air should not leak at all if system fixed properly.
First things is find the leaks. Spray all connections with soap water to check bubbles. Leaky quick push in connectors can be repaired changing O-rings inside.
Don't oversight air lines to driver seat and passenger seat, they are can leak to.

 

I think some trucks tend to hold air longer than other trucks do,

X1 is correct. If the truck passes the air brake test it's safe to drive.

But if it were my truck and it completely lost 100% of the air just overnight, I would get a soapy spray bottle fill everything up with air and I would follow all the lines tanks fittings Valves and just spray everything down and try to find anything leaking.

And by the way, that is a great username.

 

Overnight loss of all air pressure is excessive but may still be safe. Others have already mentioned the soapy water test for air connections. If you are losing air pressure overnight, you probably have a problem developing, even if it's not a real problem yet.

 

If both tanks leak out, the main issue is probably before the tanks. Unless, of course, there are multiple issues.

 

Honestly if it passes the air system leakage test it is road legal. Now if you want the truck to hold air better, shut down the truck and listen all over for leaks. Spray down valves and fittings with soapy water. Repair the leaks as you find them and it'll hold air longer.

 

Reasonable? Borderline, But not on my watch. . Legal, yes.

Something isn't right, but it's not a show stopper. I'd get a spray bottle with a little bit of dish soap and water in it. climb underneath and spray all the air line fittings and look for bubbles. Some of those compression fittings just need to be pushed in a little bit more to get them to stop leaking. Need to drain the air pressure after you find the leak, the fittings are easier to push in.

 

Mine is empty in about 6 hours. Passes all tests and does just fine. Pain in the ### sometimes but workable. Some day I'll get to the air leaks.

 

If you have a heat-stressed or cracked air line, you might lose it completely at any time. 6 hours might still be legal, but I would spend a couple hours looking for that leak, for sure.