|
The Motorcycle and Side Car Testers Manual
Appendix B Assessment of Corrosion
Assessment of Corrosion
|
The effect of corrosion on the safety of a motorcycle Is a difficult
matter to resolve since it depends not only on the extent of the
corrosion but also on the function of the section in which it has
occurred. A small amount of corrosion which substantially weakens
an important component or part of the structure would render the
machine unsafe, whilst significant corrosion of a less important
part may be acceptable.
Where corrosion is present the tester must make an assessment of
its severity and identify whether it is in a load bearing member
or a highly stressed part such as a frame or suspension component,
reaction bracket etc. The extent of the corrosion should be determined
by pressing hard with finger and thumb. If necessary careful scraping
and light tapping of the affected areas with the Corrosion Assessment
Tool is permitted. Sharp instruments or heavy blows must not be
used. Excessively corroded metal or metal treated with filler (which
may camouflage corrosion) emits a duller sound than uncorroded metal.
Having determined the extent of the corrosion the tester must use
his experience in judging whether the degree or position or the
corrosion has significantly affected the strength of the part having
regard to the amount of sound metal remaining. A further criterion
which may be applied in judging a part which is excessively corroded
is whether it is likely to make the machine dangerous to use on
the road under any condition of use including fast cornering, emergency
braking etc. If the tester considers the machine would be safe to
use the component should not be regarded as defective: however the
tester should advise the owner of the presence and location of this
corrosion. On the other hand if the strength of certain parts is
very seriously reduced by corrosion the tester may refuse to carry
out a brake test. (Ref: Introduction: item 6).
Where a corroded part has been repaired it is essential that this
has been carried out using suitable materials and techniques so
that it is virtually as strong as the original part. Repairs to
load bearing members or sections by pop riveting or glass fibre
are not acceptable, but in some cases these methods may be used
for repairs to non load bearing parts. Welded repairs to highly
stressed components such as suspension arms etc are not normally
acceptable. If in doubt consult the vehicle or component manufacturer.
Brazing, soldering, glass fibre and body filler are bonding processes;
they are not regarded as strong enough for repairs to load bearing
members although they are normally adequate for other repair work.
Brazing, bonding and riveting are only acceptable where used by
the vehicle manufacturer and the standard of any such repair must
be comparable to the original.
It is sometimes difficult to distinguish between welding and brazing
after the repair has been covered in paint or underseal. However,
brazing may be detected by the smooth fillet of filler or a gold
colouration at the edge of a joint. Glass fibre, body filler, aluminium
etc may often be detected by a difference in appearance, in sound
when tapped, or by the use of a magnet.
|
Issue Date: 10th January 2005
|
|
 |
|
|
