How to replace the friction stays on your windows
Tips for fitting replacement fricion hinges
You may find it easier to remove the glass first (this makes the sash easier to handle and also lighter in weight).
Remove the sash from the frame and then the old hinges from the sash
open the new friction hinge to about half way or so you can see all of the screw holes and making sure that you open the hinge to the correct handing
place the hinge on the sash with the top locating point overhanging the sash by about 5mm and making sure that the plastic head of the hinge doesn't snag on the top of the sash. Fit your screws into the elongated holes first and check operation and adjust before you fit the last screw into the middle hole.
Offer the sash to the window frame and fit the top screw in first both sides.
you can now check to see if any adjustment is required and adjust accordingly
Fit the last screws in and check operation for correct opening.
The above tips are for guidance only. If you are in any doubt regarding the fitting of friction stays please seek professional advice.