TM10-3930-660-34 16-4.  MAIN CONTROL VALVE ASSEMBLY - REPAIR (Cont’d) 2. IF REMOVAL WAS NECESSARY, ASSEMBLE AND INSTALL TWO RELIEF VALVES (20). a.   Install new O-ring (38) on body (37). b.   Install new O-ring (33) on poppet (35).  Install back-up ring (34). c.    Install poppet (36), poppet (35), piston (32) and spring (31) into body (37). d.   Install new O-rings (28 and 30) onto plug (27). e. Install back-up ring (29) onto plug (27).  Install plug assembly (27)   into body (37). f. Install poppet (26), spring (25) and adjusting screw (24). g.   Install one new O-ring (23) into each nut (21 and 22). h.   Install nuts (21 and 22). i. Install two relief valve assemblies (20). 3. IF REMOVAL WAS NECESSARY, ASSEMBLE AND INSTALL TWO RELIEF VALVES (1). a.   Install new O-ring (19) on body (18). b. Install new O-ring (14) on poppet (13).  Install back-up ring (15). c. Install  poppet  (17),  poppet  (16),  piston  (13), and spring (12) into body (18). d.   Install new O-rings (9 and 11) onto plug (8). e. Install  back-up  ring  (10)  onto  plug  (8).    Install plug assembly (8) into body (18). f. Install    poppet    (7),    spring    (6)    and    adjusting screw (5). g. Install one new O-ring (4)  into  each  nut  (2  and 3). h.   Install nuts (2 and 3). i. Install two relief valve assemblies (1). 4. INSTALL   MAIN   CONTROL   VALVE   ASSEMBLY, TM10-3930-660-20. 5. INSTALL    BOOM    CYLINDER    FLOW    CONTROL VALVE, TM10-3930-660-20. 16-23