Vertical window blinds are commonly replaced due to broken, bent, or missing slats, and blind cords that no longer retract and extend the blinds. Generally, these problems can be easily repaired in an hour or two, saving you the cost of new blinds.
Make sure the blinds are pulled down to their full lengths, if the lift cord allows. Remove the blinds from the mounting brackets. This is easily done by sliding the top rail of the blinds out of the mounting brackets, although for some types of blinds and mounting brackets, you may need a screwdriver to take the blinds down.
Lay the blinds down on the floor or a table, so that the entire set is flat while you are working. If you are unsure what problems need to be repaired, now is a good time to look the blinds over to determine what the problem is.
Determine the cause of the problem and the best remedy for the problem. If a single blind slat is broken or bent, you will want to remove that slat to attempt to reshape or replace it. If the lift cords are broken, or no longer pulling their weight, you will need to restring the blinds, or repair the pull cords.
Use pliers to remove the caps on the top and bottom rails of the blinds. This will allow you to remove the rail from the blinds and fix problems in the top rail's mechanics and lift cord, and to remove problem blinds. You should be able to slide the railing off or remove screws and then remove the top and bottoms rails.
Untie the lift cord so that slats can be removed and replaced. For some types of vinyl blinds, you may not have to untie the lift cords to remove broken or bent slats, because the individual slats have slots instead of holes and easily slide out of the lift cords.
Remove broken or bent slats and replace with new slats, or attempt to reshape bent slats. Place the new slats back into the lift cord weave; replace the lift cord if necessary. Tie knots at the ends of the blinds to prevent the lift cord from sagging and making the blinds uneven. If the lift cord is made of nylon, you may want to melt the ends of the cord with a lighter to prevent unravelling.