WATER TIGHTNESS
After the body is operated or maintained, this is the most important instruction in this
Chapter.
If these instructions are not followed, water leakage will frequently happen inside the car, and
it would be very difficult to determine the exact position of leakage, as water inside the car
has many uncertain flows, and can possibly flow directly along the water channel.
One pattern will also be observed that there will be more or less rain leakage when vehicle is
being directionally driven in rain, while no water leakage can be found when it passes
through car cleaning station or high-pressure nozzle. The reason for this happening is because
of unevenness of the ground surface and the impact of bending and buckling stress on work
of mechanical parts, so that rainwater enters rather poorly sealed areas.
Many cases can lead to water leakage, such as:
A. Problems with connection of body for welding errors.
B. Spot welds are loosened for insufficient nicety work with metal surface prior to welding.
C. Lacking of sealing adhesive for airproof position.
D. Poor quality of sealing adhesive, or low-level sealing type.
E. Problems with fitments of water tightness for general assembly of parts, etc.
The above indicates that it is necessary for the general assembly of body to be airproofing so
as to prevent water leakage. Therefore, after parts with body are replaced or the body is
maintained, proper adhesives are to be used as per models of joints.
Adhesives should have proper viscosity, elasticity, and resistance, so that they won’t break or
loosen under the motion of body and change in temperature.
Thanks to the advanced properties of manufacturing process for general assembly, sealing
materials are not required for some positions. However, as the requirement of such process
cannot be generally met during maintenance, all the welds must be well insulated, and
corresponding sealing materials are to be applied for similar positions stipulated in this
Chapter.
S-51