distinguishing design characteristic of a channel is that it
requires replacement of the affected metal area. In
is open-ended. Insides of all channels should be
some instances, such as in the M151 series 1/4-Ton
trucks, rust repair kits are available. For the most part,
cleaned, treated and rustproofed. Exterior sides are
however, maintenance personnel should refer to the
cleaned, treated, primed and painted.
vehicle-specific TM for replacement parts.
g. Stage 3 and Stage 4 rusted metal parts classified
as unserviceable should be removed. Adjacent areas
should be thoroughly cleaned of any rust, oils, or
chemicals before replacement parts are installed.
Army policy requires that all accessible
under surfaces to be rustproofed must also
be cleaned, primed, and painted. This
additional barrier of paint will provide
greater protection to the metal.
h. Once the metal has been thoroughly cleaned,
exterior surfaces must be primed and painted (see
TM 43-0139). All accessible under surfaces such as the
underbodies of cargo and dump trucks should also be
primed, painted, and allowed to dry before applying
Figure 2-6. Channels.
rustproofing material. Surfaces that are not readily
accessible for painting, such as boxed-in areas, are
channels serving as both support members and as
structural protection for the vehicle body. The
i. After the affected surface has been prepared,
refer to the vehicle-specific chapters of this technical
horizontal crossmember trimming the tops of all cargo
bulletin for final rustproofing instructions (see Chapters
sides and tailgates are rubrails.
boxed-in or solid support members found in the
tailgates of all cargo trucks. Stiffeners strengthen the
component to which they are attached. Solid stiffeners
as found on most 2 1/2-Ton cargo trucks present little
a. This technical bulletin provides specific rust-
difficulty regarding rust. Boxed-in stiffeners found on
proofing instructions for most tactical vehicles as well as
all 5-Ton trucks, however, are prone to trap moisture.
several commonly used trailers (see Tables 1 1 and
1-2). Application of rustproofing instructions can be
applied to all vehicles. To assist in adapting such
tube-like designs such as the stake pockets used to
instructions, this paragraph provides a list of rust-prone
areas that are found in the design of most vehicles.
install the troop seat and side racks of cargo trucks.
Users are encouraged to recognize such areas and
Pocket designs are typically fully open at the top of the
understand why such areas are prone to rust. Finally,
tube. The bottom of the tube most often has a means of
users are encouraged to apply the principles of
drainage from the tube. This is not always true or
rustproofing to all vehicles and trailers using this
adequate, which makes pocket designs very vulnerable
technical bulletin as a guide. The following are likely
to rust as a result of trapped moisture.
areas for rust development:
such as window frames of fold-down type windows or
open-ended design. It maybe square or C-shaped, such
the pillars of stationary windows are especially rust-
as the rubrail support members of cargo and dump
prone due to the boxed-in design and the thin gage met-
truck sides and tailgates, or an inverted U-shape found
al most often used in their construction.
in the understructure of M191 series trucks. The