3.2    Brake Systems Information Method of Inspection Reason for Rejection A.   MECHANICAL BRAKE
COMPONENTS 1.    Examine all the mechanical components of the brakes which can
be seen without dismantling, looking
particularly for: 1.    Serious reduction in strength of any component due to excessive wear,
cracking or damage (eg a brake rod
reduced in diameter by more than
1/3^rd of original dimension) a.  badly chafed rods or levers b.  corroded, frayed or knotted cables, or crushed outer
casings c.  corroded or damaged rods, levers or linkages d.  worn clevis joints e.  absence or insecurity of locking devices f.   the thickness of brake linings or pads a.   excessive chafing to rods or levers b.   a knotted, excessively corroded or badly frayed cable or a
significantly damaged outer
casing c.   excessive corrosion or damage to rods, levers or linkages d.   an excessively worn clevis joint e.   the absence or insecurity of locking devices (eg lock nuts, split
pins etc) f.     (i)   Brake linings or pads, (other than sintered pads) less than
1.5mm thick at any point (ii)  Sintered brake pads less than 1.0mm thick at any point Some braking systems have levers
which are designed to operate over-
centre Check for any movement at the bolts
securing the back plate reaction brackets
or calipers by rocking the machine
backwards and forward with the brake
applied. Where there is doubt about the effect
of an observed defect, the tester may
at his discretion carry out a road test.  
(See Introduction item 10) Fully floating brake discs are designed to have some movement. Care must be
taken to not unnecessarily fail these
items for security. It may be necessary to use an assistant
to operate the brake/s to ascertain the
condition and adjustment of the
mechanical components. g.  insecurity or cracking of brake drums or discs g.   An insecure or cracked brake drum or disc or securing bolts
loose or missing h.  any restriction to the free movement of the mechanism i.    abnormal movement of levers indicating
maladjustment or excessive
wear j.    insecurity of brake back plates, reaction brackets or
calipers; k.  contamination of friction surfaces by oil or grease l.    brake disc scoring, pitting or wear; m. brake disc run-out. h.   any restriction to the free movement of the system likely to
impede its operation i.    abnormal movement of levers   indicating maladjustment or
excessive wear.  (see information
column) j.    an insecure brake back plate, reaction bracket or caliper.  
Securing bolts loose or missing.
(see information column) k.   contamination of friction surfaces by oil or grease l.    an excessively scored, excessively pitted or excessively
worn brake disc m. excessive run out or distortion of a brake disc. The Motor Bicycle and Side Car M.O.T. Inspection Manual Issue Date 10 January 2005