Service Manual

HY13-1521-M2/US Service Manual
General Information Series HB Hydrostatic Transmission
6
Parker Hannifin Corporation
Hydraulic Pump/Motor Division
Greeneville, Tennessee USA
Troubleshooting Guide
NOTE
Before troubleshooting any system problem, check
service literature published by the equipment and/or
component manufacturers. Follow their instructions, if
given, for checking any component other than the
transmission.
Preparation
Make your troubleshooting easier by preparing as
follows:
• work in a clean, well-lighted place
• have proper tools and materials nearby
• have an air pressure source.
WARNING
Since solvents are flammable, be extremely careful
when using any solvent. Even a small explosion could
cause injury or death.
WARNING
Wear eye protection and be sure to comply with
OSHA and other maximum air pressure
requirements.
Preliminary Checks
Hydraulic systems are often trouble-free. Hence, the
problem an operator complains of could be caused by
something other than the hydraulic components.
Thus, once you have determined that a problem
exists, start with the easy-to-check items, such as:
• Parts damaged from impact that were not properly
repaired, or that should have been replaced
• Improper replacement parts used in previous
servicing
• Mechanical linkage problems such as binding,
broken or loose parts, or slipping belts
Hydraulic Components
If you think the problem is caused by a hydraulic
component, start by checking the easy-to-reach
items.
Check all belts for cracks, hardening or other signs of
wear. Check all pulleys, fans and bolts to make sure
they are tightened to specified torque value. Look for
leaks, especially at coupling shaft, plugs and fittings.
Next, go to the reservoir and filters. Check fluid level
and look for air bubbles. Check external filter(s). A
filter with a maximum of 25 - 30 micron filtration is
recommended for the UHT system.
Visually check other components to see if they are
loosely mounted, show signs of leaks, or other
damage or wear.
Excessive heat in a hydraulic system can create
problems that can easily be overlooked. Every
system has its limitation for the maximum amount of
temperature. After the temperature is attained and
passed, the following can occur:
• oil seal leaks
• pump loss of efficiency (resulting in lower
transmission speeds)
• pump failure
• belts become hard and brittle
• pulley lose
A normal temperature range means an efficient
hydraulic system. Consult the manuals published by
equipment and/or component manufacturers for
maximum allowable temperatures and hydraulic tests
that may be necessary to run on the performance of
the hydraulic components. The UHT is not
recommended for hydraulic systems with maximum
temperatures above 280
o
F (137
o
C).