SERVICE MANUAL 4. Position    valve    and    seal    assembly    (16)    into secondary  valve  body  (21)  such  that  valve  seal rests on exhaust seat in body. 5. Install   spring   (20)   over   tube   to   rest   on   seal retainer.    Then  place  O-ring  (19)  over  exhaust valve  body  (12).    Align  exhaust  valve  body  to spring  and  push  exhaust  valve  body  firmly  into valve  body  (21)  and  hold  to  prevent  the  spring from  pushing  the  exhaust  body  out.    Install  the retaining  ring  (18)  into  valve  body  (21)  making sure ring seats properly in groove. 6. Install  new  O-ring  (27)  on  new  valve  (29)  and seal assembly. 7. Place   seal   retainer   (8)   over   tube   and   around valve seal. 8. Place valve and seal assembly (29) into primary valve    body    (4)    so    that    valve    seal    rests    on exhaust seat in valve body. 9. Install   spring   (20)   over   tube   to   rest   on   seal retainer. 10. Install new O-rings (10 and 17) on exhaust valve body   (9).      Then   align   exhaust   valve   body   to spring  and  push  exhaust  valve  body  firmly  into primary valve body (4) and hold to prevent spring from pushing exhaust body out.  Install retaining ring (26) making sure it seats properly. 11. Install O-Ring (24) on secondary piston (23). 12. Position  spring  (22)  into  secondary  body  (21); then install piston (23) into body (21). 13.Position O-ring  (11)  on  primary  body  (4)  and align  valve  body  (4)  with  piston  (23)  and  valve body  (21).    Push  the  two  valve  bodies  together and  align  with  original  alignment  marks.    Install four screws (28) and tighten to 5.7 - 6.8 N.m (50 - 60 in lbs) torque. 14. Install   shims   (30)   and   reaction   ring   (6)   into primary  piston  (31)  as  shown  in  Fig.  10.  Then install   spring   (32)   in   piston   (31).   Place   spring retainer  (1)  on  top  of  spring  and  apply  force  to depress     retainer     beyond     the     retaining     ring groove.    Be  sure  to  support  the  piston  (31)  in  a fixture  (press)  so  that  exhaust  seat  "B"  will  not be     damaged     and     install     retaining     ring     (2) properly in primary piston.  Check force required to  start  movement  of  spring  retainer  away  from retaining   ring   (2).      Use   a   hydraulic   press   to support  piston  so  that  exhaust  seat  "B"  will  not be  damaged.    Then  press  spring  retainer  and record pressure required to move retainer. If  force  is  less  than  218  N  (49  lbs),  disassemble  piston assembly, add required number of shims and reassemble.      If   force   is   more   than   258   N   (58   lbs), disassemble  piston  assembly,  remove  required  number of shims and reassemble. 15. Install O-ring (5) onto primary piston (31). Place spring   (7)   into   primary   valve   body   (4).      Align piston  to  spring  and  push  piston  (31)  firmly  into valve  body  (4)  and  hold  to  prevent  spring  from pushing    piston    out.    Install    retaining    ring    (3) making sure it seats properly in valve body. 16. Test rebuilt brake valve by performing operation and    leakage    tests    as    outlined    in    SERVICE CHECKS. CTS-4079 - CHAPTER IV - Page 15