COH7

I have a vintage Motobecane Grand Sprint. I am trying to remove the fork and headset to grease the bearings but the cone shaped[?] expansion nut is jammed inside the tube, preventing me from getting the stem off. I tried tapping down on the bolt after loosening it; that didn't work so I hit harder and that didn't work. Finally I hit it hard enough that the bolt blasted through the expansion nut, but the nut didn't move. I can not twist the handlebars or stem. I tried heating it. My next move is to cut the stem so I can get a bigger tool inside to knock out the expansion nut, but that means a new stem of course.

Anyone have a better idea? Thanks.

JohnDThompson 

Sounds like the stem itself has galled to the steer tube. Turn the bike upside down and pour some ammonia into the steer tube and let it soak overnight. Try loosening the stem tomorrow.