problem with dimension

I use linear dimension for some line and when I change scale of line dimension also change. How to set that dimension wouldnt change when I change a scale of line?

You mean leave the dimension and let the line move? As long as its "attached" to the line being scaled, it should follow it.

Yes, but how I can lock the dimension?

Sounds like you need to over write the dimension in MODIFY>PROPERTIES.

Or even explode the dimension

Just pull the dimension off a bit, then put it back.

If you edit the dimension and put some text as a replacement, the new dimension (text) will not change.

i think if you click on the line enough times you can get up the properties toolbar, then the menu at the bottom will have a box called text overide, just type whatever value you need in there. sorry i can't be more precise as i dont have autocad infront of me right now.