Awesome! Thanks!

It's your standard 3/8" O.D. DOT brake tubing.

@@fleetrepairsolutions6372 thank you

Most likely the height control valve / leveling valve is defective, incorrect or set wrong. But first check for any kinks or leaks anywhere in the air suspension plumbing, even a small leak can cause the airbags to air up slow or not at all. Next I would check the supply tank is getting sufficient pressure from the tractor. After that I would check the operation of the height control valve / leveling valve.

Installed new height valve and no air leaks . I keep hearing like the tank still airing up . Can a tank be defective?

I feel like the pressure out of the tank should be stronger . Does the same thing even with a different tractor . So it’s not on the truck side .

Can the tank be defective? Can the pressure relief valve didn’t let air out meaning it’s not enough pressure

The tank could be bad, but you would hear the air leaking. You say you hear air constantly moving through the tank...Do you have any thing else plumbed to the air tank that could be consuming air like a tire auto inflation system? If you have a tire leak the system will use the supply tank pressure to try to fill it up, leaving inadequate air pressure to deliver out to the air suspension.

I'm assuming you are talking about the type of dock stabilizer system with the 2 arms that pop out when you release the trailer brakes? If so then no, the air that inflates that small air bag that pushes the arms out is split off of the red supply line, before the air tank. The PPV protects the air inside the tank for braking. It's pretty common for that style of dock stabilizer to slam open, just don't be around the arms when they do... The trailer dropping you saw at 6:30 happens sometimes on a trailer with this type of suspension when you release the trailer brakes while unloaded.

@@fleetrepairsolutions6372 ok cool. Thanks so much for the explanation and clarification. I replaced the PPV for my trailer and it air up pretty quickly. But it was an aftermarket. I now have the Haldex original that the trailer came with and will install that one instead. Hopefully it'll fill up faster once the tank is charged.

The trailer supply tank is fed by the red glad, down the trailer through red brake tubing and enters the supply tank via the emergency relay valve. With your trailer brakes released, confirm there is no major air leaks at any of these locations. If no leaks are found the next most likely cause for the tank not airing up would be the emergency relay valve malfunctioning. Depending on the style you have these are an easy and inexpensive replacement.

What if the bags over inflate I've tried switching the leveling valve the pressure valve still over inflates

@@nathanmorgan2917 The pressure protection valve is probably working. It only shuts off air to the accessory it's plumbed in line with when air tank pressure drops below a certain level. There's no upper limit on the PPV, so if the tank has 125 psi, the PPV will deliver 125 psi the the accessory, in this case the air bag. The volume of air that reaches the air bag is controlled by the moveable arm on the height control valve. Raising the lever adds more air to the bags, and lowering it let's air out. Your problem may be that the ride height is set incorrectly, meaning the adjustable rod that is connected to the height control valve arm is set in the wrong position and letting too much air into the air bags.