Bellows are an important part of a cuckoo clock, as they are responsible for the "cuckoo" noise that it makes. There are two bellows inside a cuckoo clock. To make the "cuckoo" noise, one bellow moves air through it, sending it through a slot in the side that functions much like a whistle. Shortly after, the second bellow does the same to complete the sound.
Open the back of the cuckoo clock and locate the bellows. The bellows consist of two tubes with flat tops.
To remove the old bellows, you have to remove the lifting wires. These are attached to pins or staple-like pins. Use a small flat screwdriver to open a larger hole in the lower hole of the bellow top. You will be able to slip the wire through. Remove the bellows by unscrewing the screw that holds them to the clock.
Take your new right bellow, and run the new lifting wire from the wire assortment through the pin in the bellow top. Hang it the same way that the old bellow was attached. Do the same with the left bellow.
Replace the back of the cuckoo clock.
If money is an issue, many parts of the old bellows can be used with the new bellows, as long as they are not broken. Bellow tops, lower parts of the bellows and wire assortments can be used instead of new parts.
Make sure not to order just the bellow bottoms if the bellow tops are also damaged.