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.
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The brake fluid level check is confined to transparent reservoirs where
these can be seen. Removal of reservoir caps is not a requirement.
A hose is to be failed for cracking or chafing only if it is severe enough
to expose the hose reinforcement.
Damage to a protective sleeve may be acceptable provided the pipe or hose
to which it is fitted is not damaged
It may be necessary to use an assistant to operate the brake/s to ascertain the
condition of the hydraulic components
When testing motorcycles, fitted with replacement brake hoses with anodised alloy
banjo fittings, give close attention to the union nuts, as all alloy fittings
are not recommended for road use.
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A.
MECHANICAL BRAKE COMPONENTS
1. Examine all the mechanical components of the brakes which can be seen without
dismantling, looking particularly for:
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
g. insecurity or cracking of brake drums or discs
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.
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B. HYDRAULIC COMPONENTS
1. Examine where practical hydraulic reservoirs and cylinders for:
a. security of mountings
b. excessive damage or corrosion
c. presence of reservoir cap
d. fluid level
e. leaks
2. Examine all visible brake pipes for:
a. chafing, corrosion, damage
b. security
c. fouling and leaks
3
Examine all flexible hoses for:
a. chafing, twisting or kinking
b. deterioration, stretching, fouling.
4. With each hydraulic system held under pressure, check for fluid leakage and
hose(s) bulging.
5. On machines with linked type braking systems check all master cylinder and
caliper pivot points for freedom of movement and wear. |
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 1/3rd of original dimension)
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
g. An insecure or cracked brake drum or disc or securing bolts loose or missing
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.
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1. A reservoir or cylinder:
a. insecurely mounted
b. severely damaged or corroded
c. with reservoir cap missing
d. with dangerously low fluid level
e. leaking hydraulic fluid
2. A brake pipe which is:
a. Excessively chafed, corroded or damaged
b. rigid pipes inadequately supported
c. pipes or hoses likely to be fouled or trapped by moving parts
3. A hose which is excessively:
a. chafed, twisted or kinked
b. deteriorated, fouling or can be stretched by steering or suspension movement.
4. A hose which bulges or any part of the system leaking fluid.
5. An excessively worn or seized master cylinder or caliper pivot. |
