My front ride height valve has been slow to rise, esp in cooler weather. Had to shoot it with a heat gun to get it to raise. Finally got around to replacing it. The hardest part was taking off the LF tire. My impact wrench JUST barely loosened the lugnuts. Replacement was a breeze; all the air connections are those Chinese finger trick connections so easy to disnconnect and reconnect. My biggest worry was that the two bolts that fastened it to the frame rails would fall backwards and it would be a dog to try to access them from the other side of the frame. I oh-so carefully loosened them using the valve bracket to bind them so I could get the nuts off. After I had the valve off, I carefully pushed them backward and dicovered the factory had put a piece of tape or something over the bolt head so they wouldn't push out. They would spin but not push out. I again twisted the bracket to bind them to tighten the nuts. Marked everything, connected everything and it works fine, The new valve is noisier when I dump the air but oh well, it works.
I marked/scribed the valve body and arm and reassembled it the way I took it apart. I have never measured the ride height yet. Will look into doing that at some point or may let the service folks do that the next time I have it in. I hate crawling underneath the beast.
Just replaced my front valve on 2005 Alfa and my valve now makes more noise when letting the air out. Set my ride height for the 10 inch spec. I didn't check if the new Freightliner valve is made in China!