I think you need to look seriously at your air system.
You should not have the problems mentioned.
This is a pre-trip routine for any air equipped vehicle. It is readily available from any State or Provincial web site. I just picked the first one that came up.
For your own safety and other users on the road, I recommend your system be looked at by a professional, if you cannot pinpoint the specific problem on your own.
You are loosing air when the brake system is charged. I would suspect a bad 'MAXI" brake pot on the rear axle. You should be able to hear that if you chock the wheels, charged the air system, shut off the engine, and listen in the area of the rear axle.
Note: these "MAXI" pots are spring loaded and extremely dangerous if you don't know what you are doing. Just have the shop replace them if needed. They are not expensive.
The air suspension leakdown is probably just a slow leak at a fitting, or on one of the lines close to the engine, that is exposed to high heat. Use a spraybottle with soapy water to track the leaks down.
Originally Posted by PSchw
I assumed if I can lower it with a switch it should not lower on its own.
My air system for the brakes which I assume is connected just got a little over 100psi. If I step on the brake 4 or 5 times hard I loose air pressure to the point that my low air pressure alarm comes on which is below 60psi.
The pressure goes in 3 days down to 65 psi.
Not sure if that is all normal?