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Venting the Boom Hydraulics
If the hydraulic cylinders or hoses have been dismantled, it is necessary to vent the cylinders after reassembly.
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DANGER! Failing to vent the hydraulic system when needed may result in violent boom movements and poor boom
performance. Risk of damage to the boom parts or foreign objects nearby. Risk of severe injuries or death.
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ATTENTION! Not all hydraulic cylinders have a venting option. In this case you must loosen the hydraulic hose
connected to the cylinder to let the air out this way. Note that ORFS fittings are used - be careful not to damage the
sealing O-ring, when venting oil.
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ATTENTION! The following venting instructions are for double acting cylinders only. For single acting cylinders, such
as for the boom tilt motion, the venting is easily completed: After service, apply hydraulic pressure to the cylinder,
retract and extend the piston approx. 5 times, and the air is then removed from the system automatically.
Sequence of Cylinders for Venting
To complete an efficient venting of air in the system, this sequence should be followed.
1. Boom centre: Cylinders for inner sections on boom wings.
2. Boom wings: Cylinders for middle sections.
3. Boom wings: Cylinders for outer sections.
4. Boom centre: Cylinder for slant motion.
Venting Procedure
Follow these steps to complete the venting. Both venting screws or valves (A and B) are closed to begin with.
1. Cylinder piston is retracted.
2. Remove the dust caps from the venting valves.
3. Mount a clear 5 mm hose to the venting valve (A) and lead it into
a suitable container.
4. Open the venting valve (A).
5. Activate the hydraulic oil pressure and extend the piston fully.
6. Close the venting valve (A) and remove the hose.
7. Mount the clear hose to the other venting valve (B).
8. Open the venting valve (B).
9. Activate the hydraulic oil pressure and retract the piston fully.
10. Close the venting valve (B) and remove the hose.
11. Repeat steps 3 - 10 a few times until air is no longer visible in the
hose.
12. Refit the dust caps. Venting is completed for this cylinder.
13. Check your hydraulic oil level - top up if needed.
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DANGER! Be careful when operating the cylinders. Make sure that no unauthorized persons are in the working area,
when folding or unfolding the boom! When retracting the pistons into the cylinders, keep fingers, tools and clothes
away from the piston. Risk of getting trapped between moving boom parts or folded boom sections resulting in
severe injuries or death.
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ATTENTION! Depending on the boom design, it might be more practical to begin with the cylinder extended.
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ATTENTION! A helping hand is useful to complete the venting procedure.
6 - Maintenance
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