Does it play an extra big part in car manufacture? (6)
I believe the answer is:
bumper
'does it play an extra big' is the definition.
I can't tell whether this definition defines the answer.
'part in car manufacture?' is the wordplay.
'part' becomes 'bum' (bum is a kind of part).
'in car manufacture?' becomes 'per' (I can't justify this - if you can you should give a lot more credence to this answer).
'bum'+'per'='BUMPER'
Can you help me to learn more?
(Other definitions for bumper that I've seen before include "Something big" , "end on a car" , "Protective vehicle bar" , "jumbo" , "Glass filled to brim" .)