HYDRAULIC SYSTEM
SUBSECTION 5A
DEVELOPING SYSTEMATIC PROCEDURES. Analyze the
have a low viscosity will increase the internal leakage of
system and develop a logical sequence of looking for
components resulting in a heat rise. Cavitation and slippage
trouble. Ask the operator how the machine performed when
in a pump will also generate heat.
it started to malfunction or if there is anything unusual
about it. Operate the machine to see if gauges are reading
2. Excessive noise means wear. misalignment, cavitation
properly, that all controls operate smoothly, and check for
or air in the oil. Contaminated oil can cause an unloading
unusual noises. Visually inspect the machine looking for oil
valve (or relief valve) to stick and chatter. These noises may
leaks. Examine filters and all lines checking for heat, loose
be the result of dirty filters, or fluid, high fluid viscosity, ex-
connections, or collapsed hoses. Develop a cause andeffect
cessive drive speed, low reservoir level, or loose intake
troubleshooting guide similar to the charts which follow.
lines
The initial time spent on such a project could save hours of
downtime.
RECOGNIZING TROUBLE INDICATIONS. The ability to
MAINTENANCE. Three simple maintenance procedures
recognize trouble indications in a specific system is usually
have a great effect on hydraulic system performance, ef-
acquired with experience. However, a few general indica-
ficiency, and life. They are:
tions can be discussed.
1. Change (or clean) filters.
1. Excessive heat means trouble. A misaligned pump
2. Maintain a sufficient quantity of clean hydraulic fluid of
places an excessive load on bearings and can be readily
the proper type and viscosity in the reservoir.
identified by the heat generated. A warmer than normal
return line indicates that the system is operating at the un-
3. Keep all connections tight, but not to the point of distor-
loading valve (or relief valve) setting. Hydraulic oils which
tion, so that air is excluded from the system.
Chart 5A-1 Excessive Noise
5A-3
