Pedal expert read legal parts (7)
I believe the answer is:
treadle
'pedal' is the definition.
('treadle' can be a synonym of 'pedal')
'expert read legal parts' is the wordplay.
'parts' indicates the answer is hidden within the clue (part of the clue provides the answer).
'TREADLE' can be found hidden inside 'expert read legal'.
(Other definitions for treadle that I've seen before include "Foot-operated lever" , "Rocking lever operated by foot" , "Rocker in a factory" , "Machine foot-lever" , "Related (anag.)" .)