TRUCK SERVICE MANUAL TM 5-4210-230-14&P-1 FRAMES GENERAL Since   the   frame   is   depended   upon   to   keep   the   major components of a vehicle in their relative positions, it is highly important that the frame be kept in good condition at all times. TYPES Because   International   chassis   are   manufactured   with frame  rails  of  either  cold  rolled  steel,  heat  treated  steel,  or aluminum alloy, each must be handled in a specific manner to assure maximum service life. IDENTIFICATION No unusual difficulty should be encountered in identifying aluminum alloy frames.  These side rails and cross members are  made  of  thicker  material  than  are  the  components  of  a comparative size steel frame.  If there is any doubt, use a file to  expose  the  material  hardness  or  color.    There  are  several methods   of   identifying   heat   treated   frame   rails,   the   most common  of  which  is  a  stencil  marking  on  the  inside  middle section   of   the   rail   or   a   stencil   mark   on   one   of   the   cross members.    The  stencil  notes  that  the  rail  is  heat  treated  and rail flanges must not be drilled or welded.  This is to caution against the welding of additional brackets or crossmembers or the welding of full length reinforcement rails.  Minor repairs as indicated in later paragraphs are acceptable. A   number   of   the   heat   treated   frame   rails   have   small patches covering "Brinell" test mark along the inside (web) of the   rail.      These   patches   are   at   about   three   or   four   foot intervals.    The  patch  can  be  removed  to  expose  the  "Brinell" marking. Some rails are stamped "H" for heat treated, on the upper face of the rail flange about three inches from the rail end. ALIGNMENT Method Of Checking A  satisfactory  method  of  checking  the  frame  and  axle alignment, particularly when a body and cab is on a chassis, is  to  mark  on  a  level  floor  all  points  at  which  measurements are  to  be  taken.    Tack  or  tape  pieces  of  paper  to  the  floor directly  under  each  point  of  measurement  on  the  chassis  as indicated by the letter "K" in Figs.  1 and 2.  Use a plumbbob since the points of measurement must be accurately marked in   relation   to   the   frame   in   order   to   obtain   a   satisfactory alignment check. After each measurement point has been carefully marked on the floor, proceed as follows: 1. Locate center line of chassis by measuring front and rear   end   widths,   using   marks   on   floor.      If   frame widths check, draw center line on floor, full length of chassis.  If frame widths do not check, lay out center line as follows: 2. Center line can be drawn through the intersection of any one pair of equal diagonals (A-A, B-B, C-C, D-D) and   center   point   of   one   end   of   frame   or   through points   of   intersection   of   any   two   pairs   of   equal diagonals. 3. Measure distance from center line to opposite points marked  over  entire  length  of  frame.    Measurements should not vary more than 1/8" at any point. 4. Measuring    diagonals    (A-A,    B-B,    C-C,    D-D)    will indicate     point     where     misalignment     occurs.          If diagonals in each pair check within 1/8", that part of frame included between points of measurement may be    considered    in    satisfactory    alignment.        These diagonals should intersect within 1/8" of center line. Axle Alignment With Frame After  determining  that  the  frame  is  properly  aligned,  the axle    alignment    with    the    frame    should    be    checked    by comparing diagonals. Dimensions for side elevation of frame should be checked at the points indicated should not vary more than 1/8". REPAIR    AND    REINFORCEMENTS    (Non    Heat    Treated Frames) Cutting Whenever  it  is  necessary  to  cut  the  frame,  the  side  rail should   be   cut   at   an   angle   of   45   degrees.      This   method distributes  the  cut  and  weld  over  a  greater  area  than  a  cut made at right angles with the rail. Reinforcing Reinforcements  can  be  made  with  flat,  channel  or  angle stock.      Because   of   difficulties   encountered   when   inserting channel  reinforcements  into  the  frame  side  rails,  the  use  of angle reinforcements is acceptable.  When ever possible, the reinforcement   should   extend   from   the   front   axle   to   slightly beyond  the  rear  spring  front  mounting  bracket  as  shown  in Fig.  3.  This procedure, of course, may CTS-2037-A  Page 2 PRINTED IN UNITED STATES OF AMERICA