Originally Posted by wigwag
So... what little bit of something should I buy to replace them? And will I need to completely dismantle the windows to do it?
The window operator is supposed to slip in the small channel of the window frame.
The end of the operator arm uses a nylon friction pad.
Removing the arm, will allow to to inspect the end of the arm. Look for a small slot in the window channel. That's where the arm is removed and/or reinserted.
If the nylon pad is gone, or worn out, that won't stop the operator from opening a window and keeping it open.
Perhaps you have some bad window operators where the internal gears are stripped.
If so, replacement operators are available.