Breakdown service returns cards and takes over vehicle (8)
I believe the answer is:
carjacks
'takes over vehicle' is the definition.
Although both the answer and definition are verbs in their -s form, I cannot see how they can define each other.
'breakdown service returns cards' is the wordplay.
'breakdown service' becomes 'rac' (I can't explain this - if you can you should believe this answer much more).
'returns' says the letters should be written backwards.
'cards' becomes 'jacks' (jack is a kind of card).
'rac' reversed gives 'car'.
'car'+'jacks'='CARJACKS'
'and' is the link.
Can you help me to learn more?
(Other definitions for carjacks that I've seen before include "Commandeers estate" , "They give access to flat there" .)