(1) Place grip safety, valve lever, and rocker arm in position in right valve grip. (Fig 48) Be sure the shorter end of rocker arm is at the top. Place grip spring over spring pin. Slip short end of grip spring in groove of rocker arm. Place long end of grip spring on outside of grip safety. (2) Put left valve grip in place and insert the two lower lock washers and screws. Tighten the two screws enough to hold parts in place and still leave space for moving long end of spring into the groove in grip safety. Push spring into groove with a screw driver. (Fig 49) (3) With spring in place, fully tighten the two screws with screw driver. (4) Place grip support in position, and insert the two upper lock washers and screws. Tighten screws, using screw driver. (5) Attach valve grip to valve body, using the four lock washers and inserting the four screws through the grip support. Make sure that the yoke shaft of the valve-diaphragm assembly is in front of rocker arm. _d. Maintenance of valve grip._ No maintenance is required for the valve grip other than replacement of worn or damaged parts, tightening of screws, cleaning, and lubrication. (Par 49) 75. BARREL AND VALVE-BODY ASSEMBLY. _a. Description and functioning._ (Fig 47) This assembly is part of the fuel valve. It includes the barrel, valve body, and operating parts contained in the barrel and valve body. The assembly consists of: (1) _Valve body_, an aluminum housing, located at the rear of the gun and mounted on the grip support by means of four screws and lock washers. The valve body has four large threaded openings. The lower opening leads into the valve grip. The side opening, which forms a Y with the main portion of the body, is connected to the fuel-hose assembly. The front opening is screwed on the barrel. The rear opening is closed by the spring retainer and plug. (2) _Valve-diaphragm assembly_, which transmits and reverses the movement imparted to it by the rocker arm of the valve grip. (Par 74 _a_) It also serves as a seal, keeping fuel from entering the valve grip. The valve-diaphragm assembly includes: (_a_) _Yoke shaft_, on which the rocker arm bears at the lower end of the shaft. (_b_) _Yoke_, a Y-shaped metal part which fits on the upper end of the yoke shaft and is held to it by a steel pin. The yoke transmits motion from the shaft to the yoke block, and is located within the valve body when the valve is assembled. (_c_) _Diaphragm_, a synthetic-rubber diaphragm held in a steel sleeve, which fits snugly in the lower opening of the valve body. The yoke shaft passes through the diaphragm. (3) _Diaphragm support, washer, and cap_, which hold the valve-diaphragm assembly in place in the valve body.