Bell OH-58A Technical Manual page 153

BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAINING
(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)
IN EITHER CASE, DAMAGES SHALL BE REPAIRED BY STANDARD
9 - 1 . SCOPE. The OH-58 hydraulic system
operates at pressures of 575 to 625 psi.
This pressure is produced by the
hydraulic pump (9, Figure 9-1). The
hydraulic fluid is routed to the flight
control servo actuators by means of flex
hoses, tubes, mechanical valves, and an
electrically controlled solenoid.
9-2. GENERAL. This chapter contains
field fixes applicable only to the hoses
and tubing which the hydraulic system
utilizes. Refer to Figure 9-2 for
system fluid distribution.
9-3. ASSESSMENT PROCEDURES. N
assessment procedures are needed to
locate leaks and ruptured hoses and
9-5. GENERAL.
a. Replacement lines may be manufac-
tured in the field if materials and
tools are available.
NOTE
Never discard MS fittings, they
are reusable. The MS21922
sleeve is not reusable.
b. Replacement lines and hoses need
not be routed along the path of the
original installation.
routed along any convenient path as long
as they do not interfere with personnel
or with operating equipment.
and hoses should be clamped to hard sup-
ports at convenient intervals not
exceeding 24 inches.
CHAPTER 9
HYDRAULIC
AT THE DISCRETION OF THE COMMANDER.
PROCEDURES AS SOON AS PRACTICABLE.
Section I. INTRODUCTION
O
Section II. LINES AND HOSES
They may be
Long lines
lines. The location of a leak can only
be determined by visual examination.
Refer to Table 9-1 for assessment logic
of the hydraulic system.
9-4. REPAIR PROCEDURE INDEX.
Lines and Hose Replacement . .. 9-5
Tube Cutting . . . . . . . . . 9-6
Aluminum Tubing Damage . . . . 9-7
Hydraulic Hose Damage. . . . . 9-8
O-Ring, Packing, and Gasket
Application.. . . . . . . . 9-10
Hydraulic Fluid Substitutions. 9-11
c. It is considered quicker to make a
replacement hose, using the old fitting
if serviceable, than to repair a damaged
hose. Flexible hose of braided stain-
less steel with rubber center is used.
There are two types of fittings used.
One fitting is a socket and nipple
assembly, Figure 9-3. The other type
is a nipple, o-ring, sleeve and socket,
Figure 9-4.
9-6. TUBE CUTTING. When cutting
tubing, it is of utmost importance to
produce a squared end free of burrs.
Tubing may be cut with a tube cutter or
a hacksaw. The tube cutter is adaptable
for use with any metal tubing such as
steel, titanium, or aluminum alloy.
Place tubing in the cutting tool with
the cutting wheel at the point where
the cut is to be made, Figure 9-5.
TM 55-1520-228-BD
PARA.
9-1