Falls following balance checks (9)
I believe the answer is:
restrains
'checks' is the definition.
('restrain' can be a synonym of 'check')
'falls following balance' is the wordplay.
'falls' becomes 'rains' (raining is a kind of falling).
'following' means one lot of letters go next to another.
'balance' becomes 'rest' (I've seen this before).
'rains' after 'rest' is 'RESTRAINS'.
(Other definitions for restrains that I've seen before include "Keeps back" , "Keeps in check" , "Keeps under control or within limits" , "Sister ran (anag.)" .)