Bread’s in pieces — have to press on! (4,4)
I believe the answer is:
bear down
'press on' is the definition.
(I've seen this before)
'bread's in pieces have' is the wordplay.
'in pieces' indicates anagramming the letters.
'have' becomes 'own' (synonyms).
'bread' is an anagram of 'beard'.
'beard'+'own'='BEAR DOWN'
'to' acts as a link.
(Other definitions for bear down that I've seen before include "Approach threateningly - press upon" , "Exert pressure from above in raw-boned way" .)