Commercial vehicles: maintain brake automatic slack adjusters

How to maintain and check the automatic slack adjusters in your heavy goods vehicles (HGVs), public service vehicles (PSVs) and trailers.



All HGVs, PSVs and trailers over 3.5 tonnes must be fitted with fully functioning automatic slack adjusters.

This guide tells you how to maintain automatic slack adjusters and how to assess their condition.

Published 15 July 2013
Last updated 19 November 2021 + show all updates
  1. Added information about trailers licenced in Ireland.

  2. Changed to HTML format, added information about coupling sleeves and protective caps.

  3. First published.