MOTOR TRUCK SERVICE MANUAL
After each measurement point has been carefully
Since the frame is depended upon to keep the major
marked on the floor, proceed as follows:
components of a vehicle in their relative positions, it is
1. Locate center line of chassis by measuring front and
highly important that the frame be kept in good condition
rear end widths, using marks on floor. If frame
at all times.
widths check, draw center line on floor, full length of
chassis. If frame widths do not check, lay out center
line as follows:
Because International chassis are manufactured with
2. Center line can be drawn through the inter-section of
frame rails of either cold rolled steel, heat treated steel,
any one pair of equal diagonals (A-A, B-B, C-C, D-D)
or aluminum alloy, each must be handled in a specific
and center point of one end of frame or through
manner to assure maximum service life.
points of intersection of any two pairs of equal
3. Measure distance from center line to opposite points
No unusual difficulty should be encountered in
marked over entire length of frame. Measurements
identifying aluminum alloy frames. These side rails and
should not vary more than 1/8" at any point.
cross members are made of thicker material than are the
4. Measuring diagonals (A-A, B-B, C-C, D-D) will
components of a comparative size steel frame. If there
indicate point where misalign-ment occurs.
is any doubt, use a file to expose the material hardness
diagonals in each pair check within 1/8", that part of
or color. There are several methods of identifying heat
frame included between points of measurement may
treated frame rails, the most common of which is a
be considered in satisfactory align-ment. These
stencil marking on the inside middle section of the rail or
diagonals should intersect within 1/8" of center line.
a stencil mark on one of the cross members. The stencil
notes that the rail is heat treated and rail flanges must
Axle Alignment With Frame
not be drilled or welded. This is to caution against the
welding of addi-tional brackets or crossmembers or the
After determining that the frame is properly aligned,
weld-ing of full length reinforcement rails. Minor repairs
the axle alignment with the frame should be checked by
as indicated in later paragraphs are acceptable.
A number of the heat treated frame rails have small
Dimensions for side elevation of frame should be
patches covering "Brinell" test mark along the inside
checked at the points indicated and should not vary more
(web) of the rail. These patches are at about three or
four foot intervals. The patch can be removed to expose
the "Brinell" marking.
REPAIR AND REINFORCEMENTS
Some rails are stamped "H" for heat treat-ed, on the
(Non Heat Treated Frames)
upper face of the rail flange about three inches from the
Whenever it is necessary to cut the frame, the side
rail should be cut at an angle of 45 degrees. This
Method Of Checking
method distributes the cut and weld over a greater area
A satisfactory method of checking the frame and
than a cut made at right angles with the rail.
axle alignment, particularly when a body and cab is on a
chassis, is to mark on a level floor all points at which
Reinforcements can be made with flat, channel or
measurements are to be taken. Tack or tape pieces of
angle stock. Because of difficulties encountered when
paper to the floor directly under each point of
inserting channel reinforcements into the frame side
measurement on the chassis as indicated by the letter
rails, the use of angle reinforcements is acceptable.
"K" in Figs.
2. Use a plumb bob since the points of
When ever possible, the reinforcement should extend
measurement must be accurately marked in relation to
from the front axle to slightly beyond the rear spring front
the frame in order to obtain a satisfactory alignment
This procedure, of course, may