How to install a window shade
Adjusting slack and runaway shades; dealing with sticking, catching, and wobbling shades
A window shade is held in place by a pawl, a small latch that locks onto a ratchet tooth to stop the roller from turning. When you draw the shade down, it pulls the pawl away from the tooth and frees the roller. Spinning keeps the pawl pivoted outward and away from the ratchet.
When you stop the shade, the pawl drops onto the ratchet to hold it in place. Tension from the spring raises the shade. A weak spring will cause a shade to roll too slowly. To tighten the tension, roll the shade down partway, remove it from the brackets, and then roll it up by hand and replace it. Test it and repeat if necessary. To reduce tension, roll the shade up completely, remove it from the brackets, unroll it about halfway. and then replace it.
Oil the pawl sparingly if it doesn't hold the shade in place. If a shade catches as it is drawn, bend or move the brackets farther apart. If it draws unevenly, check to see if the brackets are aligned, and make sure that the shade cloth is squared off and mounted evenly at the top of the roller.
To stop a shade from wobbling as it is drawn, straighten the roller pin with pliers. If a shade falls out of its brackets, use pliers to pull the pin out a bit or bend or move in one of the brackets. To move a bracket on an inside mount, sandwich a wood shim between the frame and the bracket.