(1) If coupling washer has been removed, replace. (2) Insert coupling plug or hose nipple, tank end, in the coupling as far as it will reach. Close the two cams. (Fig 43) [Illustration: Fig 45. Coupling plug in place in tank coupling. This arrangement is used when fuel tanks are brought back for filling with gun detached.] (3) Close the coupling lock (Fig 44), being sure to push it all the way, until it covers the ends of both cams. (Figure 45 shows coupling lock correctly locked on coupling plug.) (4) If the tank coupling has been removed from the hose connector, screw it on hand tight. Anti-seize compound should be applied lightly to the threads to assure a tight joint. Use wrench to tighten the coupling until it is in the position shown in Figure 34. _d. Maintenance of tank coupling._ The coupling washer, made of synthetic rubber, should be inspected frequently. If it is damaged or swollen, remove it and replace. If the coupling leaks, inspect, and if necessary, remove and replace the washer. 71. CARRIER. _a. Description and functioning._ (Fig 46) The tank group is securely carried on the firer’s back and chest by the carrier, which includes the metal carrier frame, the canvas carrier pack, webbing straps, and cord, all of which are parts of the tank group. (1) _Carrier frame._ This lightweight, tubular-metal frame is bolted to two pairs of brackets (upper and lower) on the fuel tanks. It is also bolted to the hose connector by the frame clamp, which helps support the connector. The frame is pierced by two parallel series of holes, through which the cord (lashing) of the carrier is laced. (2) _Carrier pack._ This is a sheet of heavy canvas, reinforced on the tank side with strips of webbing. The smooth side of the carrier pack rests against the firer’s back and cushions the back from contact with the metal tanks. A series of eyelets is located on each side of the pack. (3) _Seine cord (lashing)._ The carrier pack is fastened to the carrier frame by means of hard-braided cord which is laced through the eyelets in the pack and the holes in the frame. The cord that comes on the flame thrower stretches very little under load.