applies to all mounted or unmounted, serviceable or unserviceable recoil mechanisms and equilibrators in the field or in
storage, as indicated below:
(1) On serviceable weapons in the field which will not be fired for prolonged periods. A prolonged period is 180
days for all weapons except the Towed Howitzer M119A1. Those M119A1 Howitzers with the Folds recuperator must be
exercised every 30 days, and those with the "new" LTR recuperator must be exercised every 90 days. Armored
Reconnaissance Airborne Assault Vehicle M551 and M551A1 and Self-Propelled Howitzer M110A2, which must be
exercised every 90 days when in administrative storage and every 30 days when in the hands of using units.
(2) On weapons in all types and classes of storage, in storage at manufacturer's, or in storage at overhaul
(3) On serviceable unmounted recoil mechanisms and equilibrators in the field or in storage.
c. Exercising Procedures (General).
The recoil mechanism may be seriously and permanently damaged if the extension of the piston
rod reaches the point at which metal-to-metal contact between the recoiling and non recoiling
parts occur. The distance of the piston rod extension where this occurs is given in table 2-1 in the
winches distance rod NOT to be extended" column. Never extend the piston rod the distance
given in this column. If the metal-to-metal contact distance of any weapon is unknown, do not
exceed the distance given as "maximum recoil' in the pertinent technical manual.
NEVER attempt to exercise recoil mechanisms on combat vehicle by placing cannon muzzle
against an immovable object and driving the vehicle forward to create a moving force.
(1) The recoil piston rod must be extended a sufficient distance to leave a film of fluid between the packings
and respective sliding surfaces. Move the recoil piston rod back and forth three times to make sure a satisfactory film of
fluid is reestablished under the packings. Refer to tables 2-1 and 2-2 for the distance the piston rod should be moved on
the various weapons for all methods of exercising, except when exercising with the oil pump M3 (paragraphs 2-1g and 2-
(2) The initial procedure in the exercising process is to remove discolorations on the piston rod caused by the
stuffing box packing. The cleaning must be done when the piston rod is extended the first time, as follows: retain the
piston rod in the extended position and use an oiled crocus cloth, worked in a longitudinal direction, to remove
discolorations from rod. Under no circumstances will discolorations be removed with abrasives other than crocus cloth.
With the piston rod still extended, remove the recoil cylinder head (respirator) and clean the exposed part of the cylinder,
where the recoil piston normally rests, with a fine lint-free cloth dampened with dry cleaning solvent.
If the recoil mechanism is of the type where the recoil cylinder is independent of the counterrecoil
assembly (for example, recoil mechanisms use with 8inch howitzer MI 15 and 155-mm howitzer
M114 Series), the counterrecoil cylinder head will be removed instead of the recoil cylinder head.
Remove any grit or chips from critical surfaces to prevent damage by further exercising. Apply a
thin coat of automotive and artillery grease (GM) to the exposed surfaces of the piston rod, and a
thin coat of preservative general purpose lubricating oil (PL-S) to the cylinder wall where the
packing normally rests. Take special care to prevent fingerprints being left on highly machined
surfaces. Replace the cylinder head and finish exercising.
*U.S. GOVERNMENT PRINTING OFFICE :1996-746-045/20070
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