Ride on board Ford Model T, splitting southeast (5)
I believe the answer is:
skate
'ride on board' is the definition.
'skate' can be an answer for 'board' (skate board is a kind of board). I am unsure of the 'ride on' bit.
'ford model t splitting southeast' is the wordplay.
'ford model' becomes 'ka' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'splitting' means one lot of letters goes inside another (some letters split a word into two).
'southeast' becomes 'SE' (synonyms).
'ka'+'t'='kat'
'kat' inserted into 'se' is 'SKATE'.
Can you help me to learn more?
(Other definitions for skate that I've seen before include "Large edible ray" , "Complete, 19-less" , "Glide on ice; ray" , "Type of ray" , "Large marine fish" .)