This Monday when I left for work, temp in the 20s, my brake pedal was very hard to press, and I could hear air when I pressed it. After work when I left to go home, after being parked in the sun in above freezing temperatures, the brakes worked fine. Today, at 4 degrees, same problem again. Since it never really warmed up today, the problem never went away. I have read, after searching, that ice forming in the vacuum line to the brake booster can cause this issue. My question is, how do I remove the vacuum line without breaking anything? The attachment point at the booster looks quite flimsy, and the manifold end does not move, and has no hose clamp or other obvious way to remove the line. I don't want to just pull harder and harder, because with my luck, I'll break some silly plastic nipple and end up having to replace the booster or manifold. Any hints?