SERVICE MANUAL DESCRIPTION The term "foundation brake" is given to those components   at   wheels   which   actually   do   the   braking. This includes such items as brake shoes, lining, anchors, drums  and  spider  or  backing  plate.    Although  the  slack adjusters,  cam  and  followers  are  not  directly  known  as components of the foundation brakes, they will be covered herein. MAINTENANCE A   regular   schedule   for   periodic   cleaning,   lubrication, adjustment and inspection should be established, usually based on past experience and type of vehicle operation. It  is  difficult  to  determine  an  exact  maintenance  interval (time  or  mileage)  since  vehicles  will  be  used  in  a  wide variety of operational applications and conditions. To    compensate    for    lining    wear,    brakes    should    be adjusted frequently to maintain satisfactory operation and efficient brakes. Refer  to  BRAKE  ADJUSTMENT  for  detailed  adjustment procedures. Drain     air     reservoirs     regularly     as     required.          Local conditions govern frequency.  Dry climates  require  less attention  than  humid areas, where it may be necessary to drain reservoirs daily. When draining air  reservoirs,  let  all  air  bleed  off  and  be sure all drainage stops. For details for the air system, refer to the appropriate air brake system section. BRAKE ADJUSTMENT Brake  adjustment  can  be  a  contributing  factor  of  brake complaints. Proper brake adjustment must be maintained.    Do  not  overlook  brake  adjustment  on  the trailer either.  Brake balance on trucks and tractor trailers is essential for good braking. Periodic checking of push rod travel or brake adjustment is essential for good braking.  Push rod travel should be checked  every  6,000  km  (4,000  miles)  to  determine  if adjustment is necessary.  Push rod travel should be kept at a minimum without brakes dragging. Inspect  brake  lining  every  19,000  km  (12,000  miles)  or every  12  months,  whichever  occurs  first.    When  brake lining   or   blocks   are   worn   to   within   1.6   mn   (1/16")   of rivets, brake lining must be replaced. If    brake    lining    is    satisfactory,    adjust    brakes    in    the following manner making brake adjustment, one wheel at a  time,  with  all  drums  in  place  and  all  slack  adjusters connected to chambers. These   instructions   apply   to   manual   adjustment   type slack adjusters. 1. With  wheels  raised  and  parking  brake  released so   that   wheels   will   rotate   freely,   check   each brake  chamber  push  rod  to  make  certain  that  it is    in    fully    released    position.        To    do    this, disconnect  push  rod  at  slack  adjuster.    If  push rod   moves   toward   (released)   brake   chamber, turn worm shaft and rotate slack adjuster toward push rod until clevis pin can be reinstalled. 2. Disengage    locking    sleeve    on    worm    shaft    or adjusting   screw   by   depressing   spring    loaded sleeve with a wrench (Fig. 1). Fig.     1     illustrates     the     locking     sleeve     in     its disengaged  position.    Be  sure  sleeve  is  held  in, disengaging   the   adjusting   screw   when   making adjustments. Use   either   an   open   or   socket   wrench   when making adjustment.  Make certain locking sleeve is   held   in,   thereby    disengaging    the        locking mechanism.  Never use a wrench on the sleeve portion. Fig. 1  SIack Adjuster Locking Sleeve on Adjusting Nut CTS-4080W - Page 3