air lift manifold valve sticking?

Hey guys I got 2 air lift manifold valves. The one that controls the front works perfect the one that controls the back seems to be sticking. It takes a good 60 pounds to lift the back end and when I dump the back, a lot more air comes out than the other manifold. And takes quite a bit of pressure to raise again. I read somewhere that these aren't made to take apart. So I'm wondering if there's a way to clean them. Any suggestions? These were on the truck when i bought it so, I done know what all has been done to it but the valves look like they haven't been tampered with, and I hate the idea of replacing350 dollar valves. Any ideas or suggestions would be appreciated.

Go to their website and look for the tech page. There usually is some way to rebuild valve blocks. I have 4 big reds on my ranger. Their webpage had detailed instuctions on it. I had a peice of paint from the tank get lodged in mine. Hope this helps