TM 9-2815-225-34&P 3-50.  ENGINE RETARDER REPAIR THIS TASK COVERS: a.  Disassembly c.  Assembly b.  Testing INITIAL SETUP: APPLICABLE MODELS REFERENCES (TM) All TM 9-2320-273-20 TM 9-2320-283-20 SPECIAL TOOLS Solenoid valve wrench (75078) 011494 TROUBLESHOOTING REFERENCES Spring tester (15434) 3375182 Para. 2-8 Jake brake socket B1465A EQUIPMENT CONDITION TEST EQUIPMENT Engine retarder removed (para. 3-21). None SPECIAL ENVIRONMENTAL CONDITIONS MATERIALS/PARTS None Oil, lubricating, OE/HDO 30 (Appendix C, Item 21) GENERAL SAFETY INSTRUCTIONS Upper seal ring (15434) 001081 Eye protection is required when removing control Center seal ring (15434) 001082 valve outer and inner springs, slave piston retainer, Lower seal ring (15434) 001083 and spring. PERSONNEL REQUIRED Automotive repairman MOS 63H LOCATION/ITEM ACTION REMARKS NOTE All  three  engine  retarders  are  disassembled  and  repaired  the  same  way.    This  procedure covers repair of one engine retarder. a.  Disassembly WARNING Control  valve  cover  is  under  pressure  by  control  valve  outer  spring.    Move  cover  down when removing screw.  Wear suitable eye protection.  Failure to comply may result in injury to personnel. 1. Two screws (2) and control Remove from brake housing (20). valve covers (1) 2. Two control valve outer Remove from control valve (21). springs (22) 3. Two control valve inner Remove from control valve (21). Retain control valve inner springs (23) springs (23) for testing. 4. Two control valves (21) Remove from brake housing (20). Use needle-nose pliers to remove. Pull control valves (21) straight up and out of their bores. 5. Harness (3) Remove from solenoid valve assembly (4). 6. Solenoid valve assembly (4) Remove from brake housing (20). Use solenoid valve wrench (011494). 3-304