6. Drain surplus oil from piston rod by holding vertically over receptacle with piston down and holding buffer rod in place. 7. Rest piston rod on blocks, remove buffer-bushing locking screw, and unscrew buffer bushing, holding piston rod by wrench on flats at front end of rod. Have supporting blocks under both ends of rod so that rod will not be strained. 8. Draw out buffer rod carefully. 9. Draw out recoil valve with fingers. Remaining parts can now be easily disassembled. Buffer head is locked in place with bronze pin, which must be driven out before head can be unscrewed. III. To Assemble Recoil Cylinder. This operation is the reverse of II. Be sure that all gaskets and locking screws and pins are replaced and are in good condition. Be sure that all parts of mechanism are perfectly clean and dry, and that oil is clean. Oil must be strained through double thickness of clean cloth and if clean oil is not available use new oil. Do not make piston-rod gland too tight. Tighten with hand and screw up with wrench one additional notch to lock gland. Fill recoil cylinder before replacing on carriage, as follows: (a) With drain plug in place and filling plugs out, pour hydroline oil into filling hole slowly to avoid the formation of air bubbles. (b) When oil is level in filling-plug openings, tilt cylinder slightly to allow escape of air and replenish oil. (c) Loosen filling plug in front end of piston rod enough to allow oil to drip, and tighten plug. (d) Replace rear filling plug, raise front of cylinder about 6 inches, and tap cylinder lightly with wood block or lead hammer to remove air. Level cylinder, fill, and replace front filling plug. Be sure that all gaskets are in place and properly centered. Note.—After recoil mechanism has been disassembled and replaced on carriage gun should be retracted 46 inches and eased back into battery slowly to be sure that it is properly reassembled. IV. To Dismount Gun. 1. Remove recoil cylinder (see I) and breechblock (see VI). 2. Raise and block up trails in horizontal position, elevate gun until axis of bore is parallel with trails, and attach retracting mechanism (see I-7) to left spring rod, retract gun about 6 inches, remove 3-16-inch split pin in left spring-rod key, and drive out key with bronze drift. Ease gun into battery slowly and permit further forward movement of spring rod until rope is slack and front end of spring-rod rests against spring cylinder cover. 3. Transfer retracting apparatus to right spring-rod, retract gun about ¼ inch, remove split pin and spring-rod key, ease gun into battery until spring-rod rests against spring-cylinder cover, and detach retracting mechanism. Note.—In this position full pressure of springs is against cylinder cover and gun is free to slide in ways. Men should be kept from in front of spring-cylinder and care must be exercised to prevent tipping of cradle to the rear, which may cause gun to slide off. 4. Bring gun to maximum depression.