Can't get the head off troy-bilt weedeater to replace the line.

Threads are left hand. Hold the black wheel and use large plier or pipe wrench to turn the knob cloclwise

I popped the black knob piece off with the back of a hammer, turns out it is a cover for the bolt underneath which was jammed so I used a wrench to loosen.

Pop the black knob piece off with the back of a hammer, it is a cover for the bolt underneath. Then hit the bolt with a hammer, when I did this the bolt loosened up and I could unscrew it. The bolt will get stuck in a locked position sometimes if you hit the bump head wrong on the ground.

Same thing happened to me, found out that the nut on the inside had stripped the plastic casing around it so it would just spin. Simple fix, forced it off breaking the black casing, but it was only 12 bucks to replace it.

I was trying to get that bolt off with everything I had. Then I read...turn in clockwise.. NOT counterclockwise. Turning it clockwise...it came right off.

I have jobmate weed eater an drive sharf keeps snapping what's my problem to fix

This troybilt video says it needs to be turned counter clock wise.
Someone stated above that it needs to be turned Clockwise.
My bump knob will not turn what so ever. It seems to be stuck. I dont have a wrench large enough to close around it to even force it off. Im going to have to see what my neighbor has.

There are 'tabs' on the side of the head, two on top on opposite sides and two on bottom, opposite sides. You only need to push the top tabs and the head will open. The only thing you need to be sure you do correctly, is put the line back into the head so the holes line up with the holes in the head. After that, yes, rotate the head using the black round button on the bottom. Push it in, turn counter-clockwise. After a few turns, you'll see that the weedeater is actually drawing in the string.