(3) If the pressure is lower by more than 5
percent, the accumulator must again be connected to
DO NOT STAND IN FRONT OF DOWEL IN CASE
Service Tool TSE 8601 and additional nitrogen added.
PISTON IS SEIZED.
Repeat steps (1) and (2).
(4) A cycling test should be performed to
(6) If the piston cannot be touched with the six
assure that accumulator is functioning properly. The
inch dowel, the following must be adhered to:
accumulator may be connected to any simple test circuit,
(a) The gas must be released by
consisting of a reservoir, pump, accumulator and a valve.
opening charging valve.
(5) The hydraulic valve should remain in the
(b) The gas end cap must be removed.
open position until the pump has run a sufficient period
(c) Inspect and determine the condition
to bleed all air from the line. With the pump still
preventing movement of the piston.
operating, close the valve. Allow pump to charge the
(d) After corrective action has been
accumulator to 3,000 PSI. Open the hydraulic valve to
made, then manually move piston all the way to the oil
allow stored oil in the accumulator to flow back into the
end with a long wooden dowel.
reservoir. Repeat this charge and discharge cycle
(e) Reassemble and charge the
several times to insure the piston is not sticking or
accumulator to the prescribed pressure.
(6) During the cycling test, inspect for possible
oil leaks at caps and discharge fitting of accumulator.
NEVER ATTEMPT TO CHARGE ACCUMULATOR
(7) When the test cycle has been completed,
WITHOUT FOLLOW-ING THE ABOVE PROCEDURE.
remove the accumulator from the test circuit.
(7) Proceed to charge accumulator by
opening valve on nitrogen bottle slowly, closing it
Always release all hydraulic pressure in the system
occassionally to allow needle on gage (1) to settle in
before disconnecting any lines.
position, thus giving the correct pressure in the
Close the oil port with a suitable plug to prevent entrance
(8) Close valve on nitrogen tank, tighten
of foreign matter during storage and shipping.
locknut on air valve, and torque to 140-160 in.- lbs.
Remove charging hose.
Engine Driven Pumps
d. Test Procedure for Accumulators.
a. General. The engine driven charging pump is a
(1) After the accumulator has been charged to
single piston positive displacement type. The ball check
the desired pressure, it should be immersed in a tank
valves and the unloading valve are automatically
containing a non-corrosive liquid and checked for proper
controlled by the accumulator pressure. The pump shaft
sealing of the packings on accumulator piston. The oil
is supported on ball bearings; a seal, pressed into the
inlet port of the accumulator must be left open during this
pump bearing retainer, prevents leakage. The pump is
test. Also check for possible leaks of the Air Valve
attached to the flywheel housing (fig. 4-49) and is driven
Assembly, (cap removed). Air bubbles in the liquid
by a drive plate bolted to the balance shaft gear.
indicate nitrogen leakage.
b. Pump Removal.
(2) Drain dry and allow the accumulator to set
(1) Close both accumulator valves.
undisturbed for a minimum period of one hour. With
(2) Release -the oil pressure in the hydraulic
Service Tool TSE 8601, recheck the gas pressure in the
accumulator. See note.
The oil pressure in the system must be released prior to
With SERVICE TOOL TSE 8601 fastened securely to
servicing the engine driven pump or other parts to
the Air Valve Assembly, loosen nut on air valve. The
prevent possible injury to personnel or equipment.
gage will indicate the amount of nitrogen gas precharge
pressure in the accumulator. Before removing gage,
tighten locknut on air valve. When using this tool, the
hydraulic pressure in the accumulator should be at zero
before attaching the gage device to the accumulator.