Break by front part of car seat (8)
I believe the answer is:
headrest
'part of car seat' is the definition.
(I know that headrest is part of car seat)
'break by front' is the wordplay.
'break' becomes 'rest' (a rest is taking a break).
'by' means one lot of letters go next to another.
'front' becomes 'head'.
'rest' put after 'head' is 'HEADREST'.
(Other definitions for headrest that I've seen before include "Support of top of chair" , "feature in car?" , "support to chairman?" , "Chair back support" , "Support on car seat" .)