HYDRAULIC SYSTEM MLC650 SERVICE/MAINTENANCE MANUAL
2-26
Published 09-09-16, Control # 229-09
Replacing a Pressure Transducer
Before replacing a pressure transducer, perform the
following test steps and replace the transducer only if any of
the test steps fail.
1. Perform the pressure transducer test. See Pressure
Transducer Test on page 2-33.
2. Attach a hydraulic pressure gauge to the suspect
pressure transducer line. See Pressure Transducer and
Accessories Manifold on page 2-10 for pressure
transducer identification.
3. If the gauge reads pressure greater than 0 bar (0 psi),
bleed the corresponding system until the gauge reads
0 bar (0 psi).
4. Repeat the pressure transducer test.
5. Verify the output signal current at the transducer is 3.84
mA to 4.16 mA at 0 bar (0 psi).
6. Start the engine and run it at idle.
7. If testing a pilot pressure, actuate the function for the
pressure being read.
8. Verify the gauge pressure and the pressure displayed at
the Pressure Transducer Test screen are within the
limits of Table 2-3
.
Table 2-3. Transducer/Gauge Pressure Agreement
To replace a pressure transducer, perform the following
procedure.
See Figure 2-24
for the following procedure.
1. Lower all loads to the ground.
2. Move all control handles to OFF and park all crane
functions.
3. Shut off the engine.
4. Place a suitable container under the faulty pressure
transducers to catch the draining oil.
5. Disconnect the electrical connector from the pressure
transducer.
6. Slowly loosen the pressure transducer only enough to
relieve pressure.
7. Remove the pressure transducer.
8. Install the new pressure transducer and connect the
electrical connector.
9. Bleed the pressure transducer circuit.
a. Connect a bleed line with a shut-off valve to the
coupler on the pressure transducer manifold and
place the end of the hose into a suitable container.
b. Open the shut-off valve (1b).
CAUTION
High-Pressure Oil Hazard!
High-pressure oil can exhaust from the pressure
transducer ports and cause minor to moderate injury.
Do not attempt to remove a pressure transducer unless
the proper procedure is performed.
.
Item Description
1a Shut-Off Valve (closed)
1b Shut-Off Valve (open)
2 Locking Pin (can be replaced with an owner-furnished
padlock)
FIGURE 2-24
WARNING
Crush Hazard!
Keep all personnel clear of the parts that will move during
the test. Serious injury can occur.
When actuating a hydraulic function to read a pilot
pressure with a gauge, the associated parts will move
when the function is actuated.
Pressure Type Pressure
Pilot ± 3 bar (43.5 psi)
System ± 3 bar (43.5 psi)
To Next Page
Loading...
Need help?
General
