6.10 If the garage door comes off the floor when you pull down on the bar, and if the cone still won't loosen, tap the bar next to the cone with a hammer to force the cone beyond the swollen portion of shaft. Maintain a firm grip on the bar; keep it firmly inserted completely into the cone; and be prepared at all times for the cone to slip, break, explode or break free from the shaft and yank the bar down.
Replacement spring procedure took me exactly 1 hours including preparation and clean-up for double aluminum garage door. Watch the DIY video on Youtube, save $$, be careful with winding the torsion springs. Rule of thumb: 7' height door garage= 7' x 4 (each 1/4 turn) + 1 = 29 turns (1/4 turn), 8' height door garage = 8' x 4 + 1 = 33 turns (1/4 turn), and so on.... https://m.youtube.com/watch?v=Z_eZc-kh40c&feature=youtube_gdata
If you want to do the repair yourself, get several phone estimates first, because rates vary widely among service companies. Most garage doors are heavy (200 to 300 lbs.), so call in three strong friends to help you lift the door and hold it open while you lock it in the full raised position with a locking pliers. Then move your vehicles and have your friends help you lower the door.

No matter what kind of door you are installing, be very careful. The instructions that follow are merely guidelines. You should read your garage door manufacturer's instructions and owner's manual very carefully before attempting either type of installation. And if you're a do-it-yourself greenhorn, skip this project and hire an experienced professional. It may be more expensive, but garage door installation is on the higher scale of DIY difficulty.