g. Hydraulic Fluid Dispenser, Aircraft, AF-5, NSN
(1) Model AF-5 Hydraulic Fluid dispenser con-
tains a buna N and nylon cord bladder in which air pres-
sure is maintained in order to eject oil from the machine.
This special bladder is approximately the same size as
the tank and when filled with air approximately fills the
The purpose of the bladder is to separate the
hydraulic fluid in the tank from the compressed air used
to expel fluid into a hydraulic system, thereby insuring
that no air or condensation will contaminate the hydraulic
fluid or brake system.
(3) This type of construction requires special
procedure in filling dispenser and charging it with com-
To fill the dispenser
(a) Close the valve at the outer end of the
(b) Open the bleeder valve located under
the pressure gauge. Do not tamper with the pressure
relief valve. This bleeder valve drains air cavity.
To deflate the bladder completely, put no
more than 10 psi of air pressure into the fluid cavity of the
tankthrough the air valve located in the filler cap. This will
reduce the size of the bladder to allow maximum oil ca-
pacity in the tank.
When all air stops coming from the blad-
der bleeder valve, thus indicating that the bladder is flat,
close the bleeder valve.
Release the air pressure in the oil cavity
of the tank by pressing the red tank air drain button.
When pressure gauge reads zero and no further air flows
from the button valve, remove the filler cap.
Pour up to 5 gallons of hydraulic fluid into
the tank. Replace filler cap and tighten with wrench.
(g) Inflate bladder through the air valve lo-
cated under the pressure gauge to 10 psi.
Bleed all trapped air from the fluid cavity
by pressing the red button valve and holding it until a
clear stream of hydraulic oil ejects.
Inflate bladder through air valve under
pressure gauge until the pressure relief valve pops. Do
not exceed 50 psi.
(j) Recharge the bladder as required. If
3-1/2 to 4 gallons of oil used to charge the tank, a suffi-
cient air cavity will be left to expel the liquid charge with
a single air charge.
Stencil the dispenserto show the specifi-
cation number of the fluid that it contains.
(I) The discharge nozzle end of the dis-
pensing line shall be wiped clean prior to and after each
use, and protected from contamination by a small
amount of plastic food wrap and rubber band.