SERVICE MANUAL DISASSEMBLY Refer to Fig. 10 for numbers in parenthesis. After    valve    is    disconnected    and    removed    from    the vehicle,  remove  treadle  assembly  or  mounting  bracket. Inspect  valve  for  damage.    If  a  valve  body  casting  is broken or shows cracks, replace valve. 1. Mark  relative  location  of  primary  and  secondary valve  bodies  (21  and  4)  for  alignment  purposes at reassemble. 2. Remove four screws (28) and separate secondary  valve  body  (21)  from  primary  valve body (4). 3. Remove piston (23), spring (22) and O-ring (11) from secondary valve body (21). 4. Remove     retaining     ring     (18)     which     secures exhaust valve body (12) in secondary valve body (21). 5. Remove  exhaust  valve  body  (12),  spring  (20), valve (16) and O-ring (19) from valve body. 6. Remove O-ring (24) from secondary piston (23). 7. Remove screw (14), washer (15) and diaphragm (13) from exhaust valve body (12). 8. Remove  O-ring  seal  (17),  seal  retainer  (8)  and rubber seal from valve (16). 9. Remove  retaining  ring  (26)  from  primary  valve body (4). 10. Remove exhaust valve body (9), spring (20) and valve (29) from primary valve body (4). 11. Remove O-rings (17 aid 10) from exhaust valve body (9). 12. Remove O-ring (27), seal retainer (8) and rubber seal from valve (29). 13. Depress primary piston (31) and remove retaining  ring  (3),  Then  remove  piston  (31)  and spring (7) from primary valve body (4). 14. Remove O-ring (5) from piston (31). 15. Place piston (31) in a suitable fixture so that spring retainer (1) which is spring loaded can be depressed approximately 267 N (60 lbf).Be    sure to  protect  primary  piston  exhaust  seat  "B"  from damage. 16. Remove  retaining  ring  (2)  from  piston  (31)  and carefully release force on spring retainer (1). 17. Remove spring retainer (1), spring (32), reaction ring (6) and shims (30) from piston. CLEANING AND INSPECTION Wash  all  metal  parts  in  cleaning  solvent  and  then  dry. Wipe all rubber parts clean for inspection. Examine rubber seals, O-ring, reaction ring and exhaust port  diaphragm.    O-ring  seals  must  not  be  cut  or  show surface   nicks   or   gouges.      Diaphragm   (13)   should   be flexible  and  show  no  cuts,  tears  or  distortion.    Rubber seals  for  inlet  valves  (16  and  29)  must  be  smooth  on valve  face  area.    There  must  not  be  any  nicks,  cuts, dents   or   imperfections   visually   evident   in   the   rubber. Reaction ring (6) must not be cut, distorted or show nicks or gouges. Examine  exhaust  valve  bodies  (12  and  9),  pistons  (23 and 31) and valve bodies  (4  and  21).  Castings  must  be free  of  cracks  and  voids.    All  surfaces  for  O-rings  must be  smooth,  round  and  free  of  deep  scratches,  dents  or gouges.    There  must  be  no  evidence  of  metal-to-metal galling   of   aluminum   surfaces.        Valve    body    flanges, threads and retaining ring grooves must not be distorted. Inlet seats in valve bodies (4 and 21) and exhaust seats "B" and "G" on pistons (31 and 23) must be smooth and free   from   cracks   or   gouges.   Examine   springs,   spring retainer (1), retaining rings and screws.  Parts should be free  of  distortion  and  corrosion.  Replace  any  parts  that are not considered serviceable.  It is recommended that parts supplied in the service repair kit be used. REASSEMBLY Lubricate   the   inside   diameter   of   primary   piston   (31), where   spring   retainer   (1)   is   guided,   with   Item   1   in LUBRICANT   SPECIFICATIONS,   as   well   as   all   other seals and sliding surfaces. 1. Install  diaphragm  (13),  washer  (15)  and  screw (14) to exhaust valve body (12). Tighten screw to .6 - .9 N.m (6 - 8 in lbs) torque. 2. Install new rubber seal onto new valve (16). 3. Install new O-ring (17) onto valve (16) and place seal   retainer   (8)   over   tube   and   around   valve seal. CTS-4079-CHAPTER IV - Page 14