Check tilt - it will help to prevent leaks (8)
I believe the answer is:
stopcock
'it will help to prevent leaks' is the definition.
The definition suggests a singular noun which matches the answer.
'check tilt' is the wordplay.
'check' becomes 'stop' (synonyms).
'tilt' becomes 'cock' (cocking is a kind of tilting).
'stop'+'cock'='STOPCOCK'
Can you help me to learn more?
(Other definitions for stopcock that I've seen before include "Water controlled by this" , "Short pipe opened by turning a handle" , "Isolating valve in pipework" , "main controller" , "Regulator of flow" .)