(2) Unscrew wing nut from valve flexible shaft. (See fig. 35.4.) Be careful not to misplace wing nut. (3) Pull clamp and shaft from stud which is welded on fuel tank. (4) With one hand under pressure tank, unclamp but do not fully open pressure-tank clamp. (5) Supporting pressure tank valve with top of right hand, push knurled socket in and away from pressure tank valve. Left hand may be placed at back of regulator tube so that tube does not bend away from socket. (See fig. 35.5.) Pull out pressure tank and valve assembly. [Illustration: FIGURE 35.2. (Added.) Pressure system disassembled, showing removable pressure tank and valve assembly, nomenclature, and Chemical Warfare Service stock numbers.] [Illustration: FIGURE 35.3. (Added.) Detachable pressure tank and valve assembly, connected to modified regulator tube assembly.] [Illustration: FIGURE 35.4. (Added.) Removing wing nut to free valve flexible shaft.] [Illustration: FIGURE 35.5. (Added.) Pushing knurled socket away from pressure tank, permitting pressure tank and valve assembly to be removed from tank group.] (6) Put cap as far as it will go over opening of the plug. (See fig. 35.6.) This prevents dust and other foreign matter from entering empty pressure tank. (7) Flame thrower is now ready to receive a charged pressure tank and valve assembly. (See fig. 35.7.) _c. Installation._ To install a charged or replacement detachable pressure tank and valve assembly, proceed as follows: (1) Remove dust cap from plug of charged pressure tank and valve assembly. (Never open pressure-tank valve with cap on plug.) [Illustration: FIGURE 35.6. (Added.) Pressure tank and valve assembly with dust cap over plug opening.] (2) Support socket and tube with left hand and insert plug in socket with right hand. If tube is not supported, it is difficult to lock the plug in the socket and it is possible that tube may become bent. Press bottom of tank until plug snaps into socket. Test by attempting to pull tank and plug from socket. Plug must not pull out; if it does, insert again and press bottom of tank. Grasp knurled collar of socket and test for end play. If collar slides freely back and forth on socket, the connection is not tight and plug should be pressed in farther. [Illustration: FIGURE 35.7. (Added.) Tank group, ready to receive a charged pressure tank and valve assembly.] (3) Replace small clamp (valve-stem clamp) over stud projecting from fuel tank, and screw wing nut on stud to secure valve flexible shaft in place. Do not use wrench on wing nut. _d. Maintenance._ Follow maintenance instructions given in paragraph 66. In addition, if leaks occur and signs of wear are visible, carry out the following procedures: (1) _Worn washer._ Replace synthetic rubber washer by disassembling socket (fig. 35.8), prying out washer, placing new washer in position, and reassembling socket.