Advance acoustic 56514925, Service Manual

Page: 143 / 260

Hydraulic System 143 Service Manual – Advance 7765 / Nilfisk CR1500
Troubleshooting
General Troubleshooting
Problem Cause Correction
General poor
hydraulic
performance.
Low oil hydraulic level. Check the oil level in the reservoir
and add oil as necessary.
Hydraulic oil temperature too high. • Check for any restrictions to or
from the oil cooler and correct as
necessary.
• Clean the cooling fins on the oil
cooler to ensure adequate airflow
through the cooler.
Hydraulic oil filter plugged. Clean or replace the filter element
as necessary.
Pump(s) failing. Check the output pressure from the
pump(s). If below specs, replace the
pump(s).
Contamination in the hydraulic system. Drain, flush and refill the system.
General Information Regarding Checking Hydraulic Pressures
Accurate measurements are the key to troubleshooting a hydraulic system. Once you obtain accurate
measurements you can compare them to the specifications to analyze a problem.
You can use digital tachometers, flow gauges/meters or pressure gauges to troubleshoot the hydraulic
system. The pressure gauge should have a range of 0 to 3000 psi (see the Special Tools section). The flow
meter must be rated to 3000 psi and 10 gal./min.
The most convenient way to check for oil flow is to check the RPM of the motor that is performing poorly.
Refer to the appropriate
Hydraulic Specifications
table to determine the motor RPM. If the motor speed is
correct, the pump is producing the correct amount of oil flow. However, this does not mean that if a motor is
running too slow the problem is in the pump.
The following information should be used to check for correct motor RPM, system pressure and relief valve
settings. The readings are nominal figures and there will be variations due to manufacturing tolerances
and system oil temperature. If any reading varies greater than 20 percent, there will be a noticeable loss of
performance and the problem should be corrected.