SERVICE MANUAL 6. Remove mounting stud nuts and remove complete spring brake assembly. If  the  vehicle  is  equipped  with  wedge  brakes,  special instructions  which  apply  to  the  actual  removal  of  the  air chambers are covered in that particular brake section. REINSTALL Prior  to  installing  a  new  brake  chamber  assembly,  be sure  that  the  pushrod  and  yoke  are  the  correct  length and  ports    are  correctly  aligned    with      mounting  bolts. New    brake  assemblies  are  furnished  with  a  203.2  mm (8") rod.   Cut  rod  the  same  length  as  replaced unit with  spring  brake  fully  released  (release  bolt  completely screwed in). 1. Assemble  parking  and  service  brake  assembly on    vehicle    mounting      bracket.  Torque  nuts  to 136-156  N.m  (100-115  ft  lbs).  Be  sure  washers are on outside of bracket and not against brake unit. 2. Connect   service   brake   pushrod   yoke   to   slack adjuster.    Refer    to    the    specific    brake    group section   if   the   vehicle   is   equipped   with   wedge brakes. 3. Connect   air   supply   hoses   to   their   respective inlets  on  parking  and  service  brake  chambers. Torque fittings to 34 N.m (25 ft lbs). 4. Adjust  service  brakes  as  outlined  elsewhere  in this manual. 5. Position     parking     brake     control     in     released position   with   at   least   620   kPa   (90   psi)      air pressure  and  apply  service brakes. Inspect both  service  and  parking  brake  air  connections and  both  chamber  assemblies  for  possible  air leakage    at    diaphragm    with    a    soap    solution. Correct any air leaks which may exist. 6. With  air  still  applied  to  the  parking  brake,  turn the  release  bolt  clockwise  until  the  bolt  is  fully engaged into the unit and the slotted nut bottoms out  on  the  head    insert.      Tighten  nut  to  61-68 N.m (45-50 ft lbs). Do not use an impact wrench. 7. Install  the  breather  cap  by  snapping  it  in  place over seal with arrow on breather pointing toward ground. 8. Remove vehicle blocks. REPLACE SPRING BRAKE DIAPHRAGMS 1. Remove  complete  brake  chamber  assembly  as a unit (refer to REEMOVE). WARNING To    avoid    hazardous  shop  environmenttal conditions,    the    warnings        listed    in        this manual must be adhered to while disassembling   the   spring      brake   chamber assembly.  Sudden  accidental release of the power spring will cause spring brake components   to   be   hurled   with   dangerous force   which         could   strike   persons   in   the area    causing    serious    personal    injury    or death.      Under   no   circumstances   should   a spring brake chamber assembly be disassembled  without    first    performing    the safeguards as described. 2. Prior   to   the   disassembly   of   the   spring   brake chamber   assembly,   check   for   broken   parking brake spring as follows: A. Inspect   the   spring   brake   chamber   clamp band  to  be  sure  it  is  evenly  seated  around the spring brake chamber. B. Screw the release bolt clockwise all the way into the unit, releasing the spring. C. Shake the spring brake chamber assembly vigorously.  A  rattling  from  within  the  head end   normally   confirms   a   broken   spring. Further  evidence  of  a  broken  spring  would be    light    resistance    when    screwing    the release bolt down. D. If   the   parking   brake   spring   is   broken   or suspected   of   being   broken   proceed   with text concerning SERVICING SPRING BRAKE   WITH   SUSPECTED   DEFECTIVE POWER SPRING or DEFECTIVE RELEASE MECHANISM. 3. If   the   power   spring   is   not   broken,   manually release     the     power     spring     as     instructed     in MANUAL SET OF SPRING BRAKE. 4. Using  a  hydraulic  press,  adjust  it  so  that    there is  203 mm (8")  of  travel available for releasing the   spring   after   the   ram   has   taken   up   some pressure on the head of the unit. CTS-4101W - Page 6