My rear shocks are very old and are shot, so I bought a pair of Monroe MA822. Saw some videos on youtube about changing it out and it seems simple enough for me. Got the car on a stand, supporting the control arm with the floorjack and took off the top nut in the trunk. Wanted to disconnect the airline before removing the 2 bottom nuts but it absolutely will not give.

After some WD40 I was able to slide back the cover thingy but the line itself is still connected and impossible to take off. All the videos make it look easy, it just pops off.

I've never done anything like this before so Im very much a noob. Am I missing a step somewhere? Do I have to remove air from the line somehow? The compressor works (I do hear it go off when I start the car after 30 sec or so), but I have no idea how to disable it or turn it off.

Any help would be gladly appreciated!

I just did this two weeks ago. Tried every method possible to remove the air line and gave up. What I recommend is to buy the Monroe AK29 air line kit. Its only about $15 and O-Reilly has it. Also buy 2 compression fittings for this line size. You will cut off about 8" on the car and also using the new ends cut about 8" off that. Splice it in using the compressing fittings being careful not to over tighten the fittings, Before slipping plastic lines into fitting make sure the inside is clean of burrs from your cut. I used the appropriate drill bit size and spun with my fingers. When done use a zip tie to keep line back out of the way but do not secure it tight. Just loosely. The compression fitting may gather ice and snow versus the smooth plastic line. Photos attached.