SERVICE MANUAL Fig.  3 Lover-Operated Two-Way Control Valve 1Lever 2Dial 3Plunger Return Spring 4Inlet & Exhaust Valve 5Inlet Valve Spring 6Plunger 7Exhaust Port OPERATION Applying When  the  lever  is  actuated  in  the  delivery  position, the hollow plunger of the valve is depressed and makes contact   with   the   inlet   valve   and   unseats   it.      In   this position the exhaust passage through the hollow plunger is  closed  and  air  from  the  inlet  port  has  free  passage through the two-way valve and out the delivery port to the device being operated. Releasing When the lever is released, the plunger is raised by the  plunger  spring  and  the  inlet  valve  moves  to  its  seat and  is  held  closed  by  the  inlet  valve  spring  and  inlet  air pressure. Any air pressure in line or lines connecting the two-way   valve   with   the   device   being   operated   will   be exhausted    through    the    hollow    plunger    and    exhaust opening near the top of the valve. MAINTENANCE Once   each   year   or   every   160,000   km   (100,000 miles)  the  two-way  valve  should  be  disassembled  and thoroughly    cleaned.    Replace    all    grommets    and    inlet valves worn or damaged in any way. SEURVICE CHECKS Operation Test Plug one delivery port and install an air pressure test gauge in remaining port. Install second  CTS-4079 C  ir pressure gauge in the air inlet line. With air connected to the inlet port, place the lever in applied position. The air gauge  in  the  delivery  port  should  read  the  same  as  the gauge installed in air inlet line. Leakage Test With   air   supplied   to   the   inlet   port   of   the   two-way valve    and    the    lever    in    released    position,    use    Leak Detector  Tester  (SE-2326)  at  exhaust  opening  at  top  of the valve (where lever enters valve) to locate any leak. Move   lever   or   button   to   applied   position   and   check exhaust opening with Leak Detector Tester (SE-2326) to locate leakage past exhaust plunger. REMOVE 1. Disconnect air lines at two-way valve. 2. Remove  machine  screws  securing  control  valve in place and remove valve. REINSTALL 1. Install valve using the machine  screws.  Position lever-operated or  push  button-operated  two-way valve   on   instrument   panel   with   body   of   valve behind  instrument  panel  and  dial  or  instrument panel plate showing on front of panel. 2. Connect all air lines and perform tests outlined in SERVICE CHECKS. DISASSEMBLY 1. Press out lever or plunger roll pin. 2. If valve is of the push-pull type, loosen jam nut at control button, then remove button and jam nut. 3. Remove plunger and plunger return  spring  from body. 4. Unscrew  cap  nut  at  inlet  port  and  remove  valve spring and valve from body. 5. Remove grommets from plunger and cap nut. CLEANING AND INSPECTION 1. Wash all metal parts in cleaning solvent. 2. Check plungers for damage. Hollow hole plunger must be clean and free of all foreign material. 3. Inspect    small    end    (exhaust    seat)    of    plunger carefully; if chipped, worn or distorted, replace. CTS-4079 - CHAPTER VII - Page 5