© May 2023
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GTZZ14EJ&16EJ Maintenance Manual
HYDRAULIC SYSTEM
Table 7-6 Hydraulic tank structure(Continued)
3 Level indicator
4 Suction filter
Air Filter
It is recommended to clean the hydraulic tank air filter
every 3 months or after 250 hours of operation, and re-
place it every 6 months or after 500 hours of operation.
The replacement interval should be shorter in harsh
working environments.
The steps to check and clean the air filter are as follows:
1. Turn off the machine.
2. Locate the air filter on the top of the hydraulic tank.
3. Remove the air filter.
4. Check the hydraulic tank air filter: air should pass
through the air filter smoothly.
5. If the air cannot pass through the air filter smoothly,
clean the air filter with a neutral solvent and then
blow dry with an air gun.
6. Check the air filter again until the air can pass
through the air filter smoothly.
7. Install the air filter back onto the tank.
Suction Filter
It is recommended to replace the hydraulic tank suction
filter screen every year or after 1000 hours of operation.
The replacement interval should be shorter in harsh
working environments.
Every time the hydraulic oil is replaced, the hydraulic
tank oil suction filter screen should also be replaced.
7.5 HYDRAULIC OIL RETURN
FILTER
It is recommended to replace the hydraulic oil return fil-
ter element after the first 50 hours of operation and
every 3 months or 250 hours of operation thereafter.
The replacement interval should be shorter in harsh
working environments.
1. Turn off the machine.
2. Open the turntable cover and locate the return filter.
3. Place an appropriate oil-collecting vessel under the
return filter.
4. Use a wrench to remove the filter housing.
5. Remove the filter element from the housing.
6. Check the seal on the mounting surface of the hous-
ing and, if necessary, replace the seal.
7. Install a new filter element into the housing and
tighten it securely.
8. Clean the hydraulic oil spilled during the process.
9. Start the machine from the ground.
10. Check the return filter and related components for
leakage.
7.6 HYDRAULIC OIL HIGH-PRES-
SURE FILTER
It is recommended to replace the hydraulic oil high-pres-
sure filter element after the first 50 hours of operation
and every 3 months or 250 hours of operation thereafter.
The replacement interval should be shorter in harsh
working environments.
1. Turn off the machine.
2. Open the turntable cover and locate the high-pres-
sure filter.
3. Place an appropriate oil-collecting vessel under the
high-pressure filter.
4. Use a wrench to remove the filter housing.
5. Remove the filter element from the housing.
6. Check the seal on the mounting surface of the hous-
ing and, if necessary, replace the seal.
7. Install a new filter element into the housing and
tighten it securely.
8. Clean the hydraulic oil spilled during the process.
9. Start the machine from the ground.
10. Check the high-pressure filter and related compo-
nents for leakage.
7.7 INSPECT CYLINDER DRIFT
The cylinder will drift down due to leakage, and the drift
is normal within a certain range. In order to ensure the
normal operation of the machine, it is recommended to
conduct drift inspection on the platform every 3 months
or after 250 hours of operation to determine whether cyl-
inder drift inspection is required.
Fully extend the main boom and place the rated load on
the platform to measure the drift from the platform to the
ground with the machine powered off. If the platform
drifts down more than 50mm (1.97in) in 10 minutes,
carry out cylinder drift inspection as per the following
procedures.
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