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I have a new hydraulic thumb to connect to a mini excavator…

I have a new hydraulic...
I have a new hydraulic thumb to connect to a mini excavator and i have 2 questions:
1) because the hoses on the attachment are full of air, is there a procedure I need to follow to bleed the air when connecting for the first time?
2) is there a convention for having either the male or female hose on the attachment be connected to the top of the cylinder, i.e., to extend the piston?
Thanks
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Answered in 45 minutes by:
12/23/2017
Mechanic: catmastertech, Technician replied 4 years ago
catmastertech
catmastertech, Technician
Category: Construction and Road Equipment
Satisfied Customers: 4,008
Experience: Field service technician for CAT 19 years.
Verified

Hello,

Most hydraulic systems can purge themselves of air. All you need to do is verify the tank is full of oil before starting. Then at low engine speed, operate the function to fully extend or retract the cylinder. Apply pressure in this direction for a few seconds then move the cylinder in the opposite direction and apply pressure again for a few seconds. Place the cylinder in the half-way position, stop the machine and check your hydraulic oil level again. Top off the oil if needed and operate these cycles and all the other cylinders for a few minutes to warm the machine oil and purge air out of any other cylinder. Stop the machine at your manufactures recommended the position to check the oil level and allow it to sit for several minutes for the oil to settle out in the air and top off the tank if needed.

The only thing to use to connect to the cylinder is using the same size hoses as the lines on the boom. You can use smaller hoses if needed to restrict flow as we do this often when space is limited or cylinder speeds are too fast. You will need to use swivel ends on at least one end of the hose for installation It is most common to use two swivel ends and then adapter fittings at the cylinder and the supply lines. Your lines may already have a threaded fitting or a flat flange end. Flange fittings are common on larger machines and will allow rotation of the hose if needed to clear other attachments or boom movement.

If you are installing hoses on the boom, be sure to follow your bucket lines and even attach your hoses to these lines to provide proper flex radius of the hose and to protect them from damage. Too short and they will not last and could become damaged easily. Also, if you run hoses the full distance to the control valve, install the hose in sections with unions to allow replacement of a section and not the full length of hose. We will make a short hose to connect to the cylinder and then longer hoses on the boom. If they are very long, we will make a third hose set to connect from the boom to the control valve.

I hope this is helpful to you. If you need more information, please let me know.

I will be glad to help as much as I can.

Thanks for using JustAnswer,

CATMASTERTECH

catmastertech
catmastertech, Technician
Category: Construction and Road Equipment
Satisfied Customers: 4,008
Experience: Field service technician for CAT 19 years.
Verified
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Category: Construction and Road Equipment
Satisfied Customers: 4,008
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