Tread content of carpet slippers going all the way back (4)
I believe the answer is:
step
'tread content of carpet slippers' is the definition.
'step' can be an answer for 'tread' ('step' can be a synonym of 'tread'). I'm not certain of the 'content of carpet slippers' bit.
'going all the way back' is the wordplay.
'going all' becomes 'pet' (I can't justify this - if you can you should believe this answer much more).
'the way' becomes 's' (Compass direction - South).
'back' is a reversal indicator.
'pet'+'s'='pets'
'pets' back-to-front is 'STEP'.
Can you help me to learn more?
(Other definitions for step that I've seen before include "Foot movement" , "Bit of mashed potato maybe" , "Stage - pace" , "Tread - stage" , "Indian garment" .)