ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL
Rev.
8
MM-8-35
Sep
20/17
NOTE: The piston must be inserted into the cylinder assembly slowly to allow the
hydraulic fluid to work through the staggered notches of the rebound rings and
the flow passage in the piston assembly.
(k) Install the piston and guide shaft assembly into the cylinder assembly. Slowly
push the piston to the base of cylinder assembly (collapsed position).
NOTE:
The guide shaft assembly will be torqued in a later step.
(l) Hand tighten the guide shaft assembly (6) to the cylinder assembly (14). Make an
index mark from the guide shaft assembly to the cylinder assembly.
(m) Install and secure oleo valve (1). Safety wire (MS20995C32) valve to mount flange
of piston shaft.
(n) Loosen the air valve.
(o) Attach one end of a clear plastic hose to the oleo valve and the other end in a
container of MIL-PRF-5606.
(p) Open the air valve. Slowly pump the strut in and out until the hose is free of air
bubbles when compressing the oleo assembly.
(q) Fully collapse the strut, tighten the air valve, and remove the hose.
(r) Torque the guide assembly using T-0169-1. Using the index mark, torque the
guide assembly to the cylinder assembly by turning the index mark on the cylinder
assembly approximately ¼ inch past the index mark on the guide assembly.
NOTE:
The oleo may be pressurized before or after installation in the helicopter. (If the
oleo is not installed, pressurize to 200 psi (1,379 kPa) and check for leaks.)
(s) Connect the nitrogen pressure line to the oleo valve. Set the nitrogen pressure
regulator to 400 psi (2,758 kPa). Remove the oleo from the vise and remove tools
T-0035 and T-0169-1.
WARNING: The piston shaft will extend when the oleo valve is opened.
(t) Slowly open the oleo valve and allow the oleo to fill until the piston shaft is fully
extended and the oleo pressure has equalized to the regulator pressure. Close the
oleo valve.
(u) Close the nitrogen tank valve, set the regulator pressure back to zero, and
disconnect the nitrogen pressure line from the oleo valve.
(v) Install the valve cap.
(w) Inspect the oleo for leaks.
UNCONTROLLED COPY WHEN DOWNLOADED OR PRINTED
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