Product Manual

wc_tx004502gb.fm
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RD12A/12K General Maintenance
7.14 Bleeding the Hydraulic System
Overview Bleeding trapped air from the hydraulic system is necessary each time the drive
system or hydraulic system is opened up. Trapped air bubbles can cause
equipment malfunctions or erratic performance.
Procedure Perform the procedure below to bleed trapped air from the exciter circuit and the
drive circuit.
1. Fill the hydraulic system with clean hydraulic oil until it is at the maximum level
in the sightglass. Do not reuse used hydraulic oil.
2. Place forward/reverse control in the NEUTRAL position.
3. Start the engine and run the machine at idle until the hydraulic oil level
stabilizes.
4. Add hydraulic oil until it is at the maximum level and repeat as needed.
5. To bleed air from the exciter circuit:
a. Turn the vibration on.
b. Run the machine for 3–4 minutes.
c. Turn the vibration off, increase the engine speed to full, and turn the vibration
on.
d. Check the hydraulic oil level and add oil as needed.
6. To bleed air from the drive circuit,
a. Slowly move the travel control lever back and forth, from forward to reverse,
allowing the machine to roll back and forth slightly.
b. Switch the engine to high idle for 15–20 seconds. Return the engine to low
idle for 1 minute. Repeat this process 2–3 times to bleed the remaining air
from the hydraulic lines.
c. Check the hydraulic oil level and add oil as needed.
7. After returning to normal operation, check the hydraulic oil level again and add
oil as needed.