TM 5-3805-260-24
CAUTION: Immediately after the diesel engine is
stopped, remove the Blocking Plate Assembly from the
pressure line for the pump to prevent any possible
damage later.
Troubleshooting
PROBLEM: Percent of flow loss for Test 23 is 10% or
MORE and flow differential for Test 23 is
more than 2 gpm higher than the flow
differential for Test 25. Tests 26 through
30 have the same flow differential.
PROBABLE REASON:
Oil aeration (low oil level, hydraulic oil that is not
the correct type, air leak in the suction line for the pump,
oil leaks in the tank such as failure of seals, loose
connections or pump cartridge is not installed correctly in
pump body).
RECOMMENDATION FOR ACTION:
A. Check oil level and type of hydraulic oil being
used.
B. Check suction line for air leaks put foam (like
shaving cream) on all connections. The
foam will be pulled into the line at any point
of leakage.
C. Remove the cover from the hydraulic tank
and inspect for oil leaks (check above the
oil level first).
D. Disassemble the pump and check for correct
assembly and damage to seals.
PROBLEM: Flow differential between each of the
Tests 26 through 30 suddenly becomes
lower at one test and the flow rate is the
same for the remainder of the tests at
higher engine speed (rpm). Example: 8
gpm differential between Tests 26 and
27, 27 and 28, 28 and 29, but 1 gpm
differential between 28 and 29 and flow
rate for Test 30 is the same as 29.
PROBABLE REASON:
Pump cavitation (restriction in the suction line for
the pump).
RECOMMENDATION FOR ACTION:
Inspect suction line and tank.
BLOCKED CIRCUIT TESTS (CHART D)
If the System Tests and Pump Tests give an
indication of leakage in the control valves and/or
cylinders that is not acceptable, do the Blocked Circuit
Tests. Blocking Plate Assemblies can be put in
each of the circuit lines. For best accuracy, do these
tests with the oil temperature approximately 150°F (near
the oil temperature for the System Tests and Pump
Tests). For parts reference see pages 4-59 through 4-
64.
CIRCUIT BLOCKING LOCATIONS
(See Tee Test Tooling Chart for parts reference)
1. Bowl, Tests 36 & 37. 2. Ejector, Tests 34 & 35.
CIRCUIT BLOCKING LOCATIONS
(See Tee Test Tooling Chart for parts reference)
1. Bowl, Tests 36 & 37.
FLOOR CYLINDER BLOCKING LOCATION
(Test 44)
(See Tee Test Tooling Chart for parts reference)
4-47
