Charles is after small framework for vehicle (7)
I believe the answer is:
chassis
'framework for vehicle' is the definition.
'charles is after small' is the wordplay.
'charles' becomes 'chas' (shortened form).
'after' says to put letters next to each other.
'small' becomes 's' (abbreviation - e.g. clothes size).
'is' after 's' is 'sis'.
'chas'+'sis'='CHASSIS'
(Other definitions for chassis that I've seen before include "Framework of motor vehicle" , "Vehicle's base frame" , "Car's structural framework" , "Vehicle base frame" , "Body framework" .)