Page 85 - 05. Subyek Teknik Mesin - Automobile Mechanical and Electrical Systems Automotive Technology Vehicle Maintenance and Repair (Vehicle Maintenance Repr Nv2) by Tom Denton

1
70 Automobile mechanical and electrical systems

Table 1.27 Gaskets and typical uses

Gasket material Examples of where used
Paper or card General purpose, such as thermostat
housings

Fibre General purpose
Cork Earlier types of rocker covers
Rubber, often synthetic Water pump sealing ring
Plastics, various types Fuel pump to engine block

Copper, asbestos, or similar Exhaust fl ange – note safety issues of
asbestos
Copper and aluminium Head gaskets

Metal and fi bre compounds, with Head gaskets
metal composites

The general rules for obtaining a good joint, with a gasket or otherwise, are as
follows:

cleanliness of the surfaces to be joined
●
removal of burrs from the materials
●
use of the correct materials
●
following manufacturers’ instructions (such as tighten to the correct torque in
●
the correct sequence)
safe working (this applies to everything you do).
●

1.6.17 Sealants

Many manufacturers are now specifying the use of sealants in place of traditional
gaskets. The main reason for this is a better quality of joint. Liquid sealants, often
known as instant gasket, are a type of liquid rubber that forms into a perfect
gasket as the surfaces are mated together. The three major advantages of this
technique are:
It is easier to apply.
●
A perfect seal is made with very little space being taken up.
●
The adhesive bonding effect reduces fretting due to vibration, and hence the
●
seal is less likely to leak.
Figure 1.97 shows a sealant being applied. A major advantage as far as the
repair trade is concerned is that a good selection of jointing sealants means you
can manufacture a gasket on the spot at any time! Note the recommendations of
the manufacturers, however, as only the correct material must be used.

1.6.18 Oil seals

The most common type of oil seal is the neoprene (synthetic rubber) radial lip
seal. The seal is fi tted into a recess and the soft lip rubs against the rotating
component. The lip is held in place by a spring. Figure 1.98 shows this type of