[punkin]

I had this same thing not too long ago. I drained all the fluid...warmed the body of the cylinder (not HOT) just warmed it up with a heat gun and kept moving the gun around. Once it was warmed up, it took a can of compressed air (like the stuff used for cleaning computers), held it upside down and directed it at the nut. Popped right out. The propellant is pretty darn cold. Probably some other ways to go about doing this but it worked for me. Actually had to do it in two locations, one at the MC and again at the union over the rear differential.