Air suspension question?

1st are you referring to the truck or trailer? Most trucks can dump the air on the drive axles some are set up to dump one or more trailer axles.
When you set the trailer brakes some dump the air on the trailer which would lower it.
Last question only if it has a leak after the leveling valve will the air suspension drop from lack of air.

 

That's right. Some trucks have an extra switch to to dump the trailer air susp., but its an add on.

 

It depends on the configuration of the truck and trailer. MOST trucks have a switch that dumps the suspension on both the drive axles. When you push in the red know it inflates the trailer. When you pull it, some trailer dump their air, some hold it. If you run out of air, suspension should deflate, unless it has some kind of check valve. It should auto adjust psi to maintiain height when load weight changes. Some trucks have a dump valve switch. when coupled with a compatible trailer they can dump one of the trailer axles air. This can help make smoother turns on a split axle trailer. Some have dual dump valves so they can dum the forn, rear or botht he trailer axles. Unless you have air ride front, your steer is most likly a leaf spring and thus cant be dumped.

If parking in bad wind, dump the tractor air with the in cab switch and pull your red knob to dump the trailer. it should be less bouncy in the wind this way.