Cherry Aerospace G-689, Оригинальное руководство пользователя

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Select a work table with a good vise. Place the head cylinder (13) in the vise with the front end cap (3) of the
head cylinder (13) up. Tighten the vise securely.
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Use the end cap socket wrench (680A173) and improvise a handle extension to 26-28". The end caps on the
head cylinder have thin hex flats and a standard socket will slip over the hex corners. The end caps on the
head cylinder (13) are factory tightened with a torque wrench from 150 to 180 ft.-lbs. (203 to 244 N-m) The
break away torque will be high - approximately 180 ft.-lbs. (244 N-m) or slightly higher.
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Remove the front end cap (3) from the head cylinder (13). Remove the four piston stops (7).
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Place the head cylinder (13) in the vise so that the rear end cap (29) can be removed from the head
cylinder (13).
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Remove the adjuster knob (36) by first removing the socket head cap screw (34) using a 3/32 hex key.
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Remove the adjuster ring (35) by removing the other socket head cap screw (34).
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Remove the rear end cap (29) from the head cylinder (13). The following parts will come out with it: socket
head cap screw (33), index washer (32), release piston sub-assembly (28), shift screw (26), shift stop (22), and
retaining ring (25).
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Push on the head piston (14). This will allow the shift piston sub-assembly to be removed from the rear of the
head cylinder (13). The shift piston sub-assembly includes the following parts: piston cap (8), O-ring (9), backup
ring (10), O-ring (11), head piston (14), O-ring (15), back-up ring (16), valve spring (17), valve stem (18), O-rings
(19 and 20), valve seat (21), shift stop (22), piston spring (23), and shift piston (24).
NOTE: Valve parts (18), (21) and (22) are matched parts and must be kept together or replaced as a complete unit by
purchasing valve sub-assembly (680A80).
To disassemble the Shift Piston Sub-Assembly:
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Insert the shift piston sub-assembly into the large hole of clamp wrench (680A48/49), locating on a polished
surface. Tighten the wrench’s cap screws securely so that the shift piston sub-assembly cannot turn in the
clamp.
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Place the clamp wrench (680A48/49) in a vise with the shift piston sub-assembly upward.
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Use the second clamp wrench (680A48/49) on the piston cap (8). Place the small hole of the clamp wrench
over the piston cap (8) and tighten the cap screws on the wrench to prevent slipping.
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Place shift piston tool (700A63) over the threads and against the shoulder of the head piston (14).
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When removing the piston cap (8), push firmly on the shift piston tool (700A63) to depress the head piston (14)
and overcome the tension created by the piston spring (23).
Caution should be used as spring will pop out if precautionary measures are not taken.
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Remove the valve seat (21) with an 11/16" wrench. Remove the valve stem (18) by pushing from front of the
valve seat (21). Remove the valve spring (17).
To disassemble the End Cap Sub-Assembly:
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Using a 5/32 hex key, turn the button head cap screw (33) counterclockwise until it stops.
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Remove retaining ring (25) inside of release piston sub-assembly with a sharp or pointed instrument.
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After retaining ring (25) is removed, use a 5/32 hex key in the same button head cap screw (33). Turn
clockwise until the shift stop (22) can be removed from the release piston sub-assembly (28).
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Place a 3/16 hex key in the end of the shift screw (26) and a 5/32 hex key in the button head cap screw (33).
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Apply a force on both hex keys until you loosen the button head cap screw (33) which is threaded into the end of
the shift screw (26).
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Remove the button head cap screw (33) and the index washer (32).
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Push the shift screw (26) out of the release piston sub-assembly (28). It may be held slightly by O-ring (27).
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Remove the release piston sub-assembly (28) from the rear cap (29) and check the small hole in the release
piston sub-assembly for debris. If the small hole is clogged, back-blow with compressed air.