Breaks the band up (5)
I believe the answer is:
parts
'breaks' is the definition.
(I know this)
'band up' is the wordplay.
'band' becomes 's trap' (both can mean a strip of material).
'up' says the letters should be written backwards (in down clue: letters go upwards).
'strap' written backwards gives 'PARTS'.
'the' acts as a link.
(Other definitions for parts that I've seen before include "bits" , "Leaves" , "Components of strap" , "Strap (anag.)" , "Areas" .)