M E 6 1 1 5 - 5 4 5 - 3 4 / 1 4 -3
Figure 14-3. Regulator Excitation Test Circuit
M E 6 1 1 5 - 5 4 5 - 3 4 / 1 4 -4
Figure 14-4. Two Terminal Brush Assembly
Section III. HYDRALIC PUMP ASSEMBLY
(CLASS 1, PRECISE SETS ONLY)
The hydraulic pump assembly supplies oil under
pressure to the electro-hydraulic actuator on Class
The hydraulic pump is located on
the left side of the engine at the rear of the timing
gear housing and is driven by the hydraulic pump
The drive assembly is driven by
the camshaft gear and contains two tapered roller
bearings which are lubricated by engine oil splashed
by other gears in the timing gear train. The pump
assembly is lubricated by circulating hydraulic oil.
14-14. Hydraulic Pump Malfunctions, Removal and
a. Symptoms and Isolation of Malfunction. A mal-
function of the hydraulic sump is usually indicated by
fluctuating frequency observed on the frequency meter
as a result of erratic hydraulic oil pressure, sluggish
response of the actuator to load changes as a result of
low hydraulic oil pressure, or failure of the governor
system due to loss of hydraulic oil pressure. To iso-
late a malfunction of the hydraulic oil pump, proceed
(1) Check hydraulic oil level by observing
sight glass on hydraulic oil sump. Insure that oil
level is sufficient.
(2) Check all hydraulic lines and fittings for
signs of leakage.
(3) Carefully examine pump and mounting adap-
ter for signs of leakage.
(4) Thoroughly clean area around fitting on
pump for hydraulic line to filter and around drain
valve on hydraulic pump.
Remove drain valve and drain hydraulic
Insert 0-400 psi gauge between pump and
line to throttle actuator.
Refill sump and start engine.
Pressure should be 310 to 330 psi. If the
reading shows erratic pressure or low pressure,
then there is a malfunction of the hydraulic pump
assembly. Proceed to the removal, disassembly and
b. Removal and Disassembly.
(1) Open left hand area engine door, drain
hydraulic oil pump and discard oil. Thoroughly clean
area around hydraulic oil fittings. Disconnect lines
from hydraulic pump.
Remove pump as illustrated
in figure 14-5. Cap all hydraulic fittings when