SERVICE MANUAL 4. Check  plunger  retainer  spring  and  valve  spring for damage. 5. Valve   body   must   be   replaced   if   seat   is   worn excessively or damaged. REASSEMBLY 1. Install new grommet on plunger. 2. Apply  a  small  amount  of  the  lubricant  listed  in LUBRICANT  SPECIFICATIONS,  Item  1,  on  the plunger   and   insert   plunger   return   spring   and plunger  in  the  body.  Plunger  must  move  freely with only a slight drag due to grommet. Depress plunger  and  then  release;  plunger  spring  must return plunger. 3. Apply   a   lubricant   comparable   to   that   listed   in LUBRICANT  SPECIFICATIONS,  Item  1,  to  cap nut grommet and position grommet on cap nut. 4. Position valve and valve spring in valve body  5. Install cap nut in valve body. 6. Position lever on top of plunger and align hole in lever with hole in body. 7. Install lever pin and stake edge of hole. 8. Install   jam   nut   and   button   on   push-pull   type valve.  Install  bracket  on  remote  control  (cable- operated) type valve. MODULAR CONTROL VALVE (BENDIX TYPE MV-2) DESCRIPTION The   modular   control   valve   (Fig.   4   )   provides   the functions of a standard three (3) valve combination plus a supply reservoir selection. The major features are: 1. Tractor protection control. 2. Trailer supply 3. Complete system park. 4. Trailer park only. 5. Trailer charge with tractor spring brakes applied (tractor park only). 6. Supply reservoir selection (two way check valve). Fig. 4  Modular Control Valve The bodies for the module, as well as "spool" inserts, are molded of a non-metallic, noncorrosive material. The assembly  consists  of  two  push-pull  valves  and  a  dual circuit  supply  valve  which  triggers  at  a  pre-set  pressure differential. The valve "spool" inserts, as well as the dual circuit  supply  valve  spool  and  shuttle,  may  be  removed from the valve bodies without disconnecting the air lines. The MV-2 valve includes a spring loaded dual circuit supply   (double   check)   valve   which   selects,   as   the   air source for both control valves, the primary reservoir at all times  unless  the  pressure  in  the  primary  reservoir  falls not   more   than   207   kPa   (30   psi)   below   that   of   the secondary  reservoir,  when  the  dual  circuit  supply  valve will  shuttle  and  establish  the  secondary  reservoir  as  the supply.   An   auxiliary   air   delivery   port   is   also   available which   receives   its   supply   from   the   dual   circuit   supply valve. All air connections are at the bottom of the valve, as shown in Fig. 5. including the auxiliary air delivery port. The   trailer   air    supply    valve    or    tractor    protection control  (red  knob)  (see  Fig.  4  )  delivers  air  to  the  trailer supply  line  and  also  will  trip  (pop  out)  automatically  and shut  off  the  trailer  supply  if  pressure  decreases  to  276 27.6 kPa (40 5 psi). IMPORTANT Reservoir No. 1 must be the reservoir that supplies the primary brake system. Reservoir No. 2 must be the reservoir that supplies the secondary brake system. CTS-4079 - CHAPTER VII - Page 6