On my 2015 Longhorn with air suspension at 120k miles, it would leak all the way down to the bumpstops and throw several codes. It would be undrivable at highway speeds due to the bouncing. I would have to pull over and use the screen to change in and out of repair mode until I could get some air in the shocks. The pump ran a lot and made a lot of noise and sounded as if it was dying.
My research showed that the air bags were most likely slowly leaking from the area of the bag that is exposed when the truck was in normal or aero mode. I disabled aero mode always parked the truck with the suspension lifted to the first offroad position. It did not leak down when parked lifted and it did not leak much at normal height. I did this for successfully for six months.
The system is open the atmosphere using 79% nitrogen. If you fill it with pure nitrogen it will eventually equalize back to 79%. Using a nitrogen bottle to refill is the best because it needs an initial charge of about 200 psi but it is not a sealed system. You hear the system release pressure when lowering. Where I live, moist, frozen air is not a problem. Some up north use some air brake line antifreeze.
The fix: I bought two rear replacement air bags both for $120 on amazon. I also bought a pair of the red and blue A/C quick connects that I could adapt to my air compressor. The red one fits the fitting on the distribution manifold. I replaced the air units and pumped the system up with as much pressure as my harbor freight compressor could muster and the on-board air suspension compressor finished the job. There is a pressure sensor that signals the compressor to run or not and the minimum to run is around 150psi. I was surprised how easy this job was and that my cost was about $150.
After the new air bags the on-board compressor never ran much and was nice and quiet. The truck rode like new and the air suspension was perfect again.
Please don't rip out wonderful air suspension until you replace the bags.
My research showed that the air bags were most likely slowly leaking from the area of the bag that is exposed when the truck was in normal or aero mode. I disabled aero mode always parked the truck with the suspension lifted to the first offroad position. It did not leak down when parked lifted and it did not leak much at normal height. I did this for successfully for six months.
The system is open the atmosphere using 79% nitrogen. If you fill it with pure nitrogen it will eventually equalize back to 79%. Using a nitrogen bottle to refill is the best because it needs an initial charge of about 200 psi but it is not a sealed system. You hear the system release pressure when lowering. Where I live, moist, frozen air is not a problem. Some up north use some air brake line antifreeze.
The fix: I bought two rear replacement air bags both for $120 on amazon. I also bought a pair of the red and blue A/C quick connects that I could adapt to my air compressor. The red one fits the fitting on the distribution manifold. I replaced the air units and pumped the system up with as much pressure as my harbor freight compressor could muster and the on-board air suspension compressor finished the job. There is a pressure sensor that signals the compressor to run or not and the minimum to run is around 150psi. I was surprised how easy this job was and that my cost was about $150.
After the new air bags the on-board compressor never ran much and was nice and quiet. The truck rode like new and the air suspension was perfect again.
Please don't rip out wonderful air suspension until you replace the bags.
