Drivers keeping jack by side in Holland (4)
I believe the answer is:
ajax
'side in holland' is the definition.
(Dutch football team)
'drivers keeping jack by' is the wordplay.
'drivers' becomes 'aa' (I've seen this in other clues).
'keeping' indicates putting letters inside.
'jack' becomes 'j' (playing card abbreviation).
'by' becomes 'x' (multiplication sign**).
'aa' placed around 'j' is 'aja'.
'aja'+'x'='AJAX'
(Other definitions for ajax that I've seen before include "side" , "Legendary warrior" , "Mythical Greek hero - Amsterdam football club" , "It's quite often seen in loo" , "Old war hero" .)