TM-9-2320-280-20 HMMWV Technical Manual Unit Maintenance Volume 2 Download
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3-49. MUFFLER AND CATALYTIC CONVERTER REPLACEMENT (M1123 AND “A2” VEHICLES ONLY) This task covers: a. Removal b. Installation WARNING Do not touch hot exhaust system components with bare hands. Severe injury will result. CAUTION Support muffler and catalytic converter during replacement. Failure to do so may result in damage to equipment. 1. Remove two clamps (12) and heat shield (13) from crossover pipe (14). 2. Remove four nuts (7) and U-bolt (25) from heat shield (11), support bracket (24), and muffler (26). 3. Loosen clamp (8) and remove heat shield (11) from catalytic converter (18). 4. Remove two nuts (10) and heat shield (4) from muffler (26). 5. Remove three locknuts (16), washers (15), capscrews (23), and washers (15) from catalytic converter (18) and crossover pipe (14). Discard locknuts (16). 6. Remove two nuts (21), lockwashers (20), and U-bolt (17) from catalytic converter (18) and support bracket (19). Discard lockwashers (20). 7. Remove manifold seal assembly (22) by pulling catalytic converter (18) towards rear of vehicle. Discard manifold seal assembly (22). NOTE It may be necessary to lower rear propeller shaft (para. 6-5) to gain access to locknuts on muffler hanger. 8. Remove four locknuts (2), washers (3), capscrews (27), washers (3), two retaining plates (28), and muffler (26) from muffler hanger (1). Discard locknuts (2). 9. Remove two locknuts (34), washers (31), capscrews (32), washers (31) insulator (29), retaining plate (33), and bracket (30) from muffler (26). Discard locknuts (34). 1. Install bracket (30), insulator (29) and retaining plate (33) on muffler (26) with two washers (31), capscrews (32), washers (31), and locknuts (34). Tighten locknuts (34) to 10 lb-ft (14 N•m). 2. Install muffler (26) and two retaining plates (28) on muffler hanger (1) with four washers (3), capscrews (27), washers (3), and locknuts (2). 3. Install catalytic converter (18) on bracket (19) with U-bolt (17), two lockwashers (20), and nuts (21). b. Installation a. Removal INITIAL SETUP: Applicable Models M997A2, M1025A2, M1035A2, M1043A2, M1045A2, M1097A2, M1123 Tools General mechanic’s tool kit: automotive (Appendix B, Item 1) Materials/Par ts Nine locknuts (Appendix G, Item 128) Manifold seal assembly (Appendix G, Item 197) Two lockwashers (Appendix G, Item 167) Manual References TM 9-2320-280-24P Equipment Condition Tailpipe removed (para. 3-47). General Safety Instructions Do not touch hot exhaust system components with bare hands. TM 9-2320-280-20-2 3-90 Change 3