Jacobsen SLF 1880, Technical/Repair Manual

Page: 143 / 236

8F-41
SECTION 8F. TRACTION CIRCUIT FIELD TEST
GENERAL
When a hydraulic failure occurs, some simple, effective
tests can be performed prior to using a test instrument.
The results of these tests can lead you to the sus-
pected component failure. More extensive test proce-
dures, using test instruments, are presented in
(Section 8G). Component location illustrations are pre-
sented in section (Section 8U). Hydraulic schematics
and Theory of operation are presented in (Section 8D)
and (Section 8E). Before performing any tests please
review As A Safety Reminder below and Preliminary
Checks below.
AS A SAFETY REMINDER
• Follow the procedures one step at a time.
• Observe all NOTES, CAUTIONS, and WARNINGS.
• Pay attention to what you are doing. Work with a
safety conscious attitude.
• Use care when working with HOT oil.
• Wear safety glasses at all times.
• Keep hands and feet away from the mower blades.
• The engine must be shut off and the attachments
lowered to the ground when making adjustments or
hydraulic connections unless otherwise specified in
the test instructions.
PRELIMINARY CHECKS
The following checks should be made before perform-
ing any tests.
1. The reservoir should be checked for proper oil
level, the presence of water (noted by cloudy or
milky appearance), air (noted by a foaming
appearance), or a rancid odor indicating exces-
sive heat.
• If any of the above symptoms appear, or if the
hydraulic oil becomes contaminated, or after a major
component failure, the system should be flushed,
the oil changed, and a new filter installed.
2. Check all lines and fittings for leakage and tighten
as necessary (Section 8C).
3. Eliminate all possible mechanical problems before
starting the hydraulic tests.
HYDROSTATIC CHARGE PUMP
TEST
The charge pump supplies oil for power steering and
charges the traction circuit with oil for proper operation.
If faults exist in both systems proceed with an instru-
ment test for the charge pump.
If a fault exists in steering, proceed with an instrument
test (Section 8G).
HYDROSTATIC TRACTION SYSTEM
TEST
1. Operate the mower until hydraulic oil is at operat-
ing temperature, 110 – 130
°
F (43 – 54
°
C).
2. Install wheel restraints or with the tractor on con-
crete or asphalt, secure the mower to a stationary
object, such as a pole or tree.
3. With the engine at high idle speed and in two
wheel drive, push the traction pedal forward.
Conclusion
• If the traction wheels break traction, the traction
pump is not at fault.
• If the traction wheels do not break traction and
engine does not labor, a fault may exist in the
NOTICE
Use only the recommended hydraulic oil
(Section 11). Always change the filter when chang-
ing the oil. The filter should be changed after the ini-
tial 50 hours of operation. Thereafter, the filter
should be changed approximately every 500 hours.
NOTICE
Before performing test, be sure tow valve, located on
the underside of the traction pump is closed
(Figure 8F-1).
8F