The M.O.T. Inspection Manual Issue Date 01 January 2012 LastPage                     NextPage                     Contents                     Back                     Forward                     Home                      3.5 Mechanical Brake Components Information Method of Inspection Reason for Rejection Brake slack adjusters are usually only found on large vehicles with air braking systems. k. restriction of free movement l. presence and security of locking devices Note: It is not always possible to determine the presence and effectiveness of certain types of locking devices e.g. locking fluid or ‘nyloc’ nuts.   m. condition and operation of brake slack adjusters n. any inappropriate repair or modification. k. restricted free movement of brake components l. a locking device missing or insecure m. a brake slack adjuster obviously defective or incorrectly installed n. a mechanical brake component inappropriately repaired or modified.