Bravo, man. Now you can remove that whole 4x4 vac harness (yes, it all comes out in 1 harness without affecting anything on the engine) and take your time getting it fixed up.
One thing I found besides plastic lines that looked like they had been chewed on by mice was the blue relief / check valve. Mine was plugged. It's designed to relieve vac to atmosphere when changing from 4 to 2 and back, allowing the vac motor to move without vac on the opposite side of the diaphragm. It should draw air in in one direction, but should not allow air flow the other way.
1990 YJ Sahara 4.2, 2011 F150 4x4, 1987 Mustang 5.0 GT (orig owner), 2006 Triumph Rocket3.