JD 3520 Backhoe hydraulic requirements

[Attono]

Hello all! I have a new JD 3520 with a FEL. I ordered it with the 3rd SCV, but it came without. I am wanting to be able to run a mechanical top link and possibly a backhoe and boom mower, so I know I need to add some rear hydraulics. My dealer tells me that I can run the backhoe with the 4th/5th SCV, which is being installed, but it seems to me that I need a power beyond kit. He tells me that the PB kit isn't compatible with the 4th/5th SCV, but I have another dealer who tells me that it is.

I got a great price on the tractor from the dealer who is working on it, but I am now having problems trusting what the sales guy I dealt with is telling me. Can I get a little help?

 

[J_J]

All open center valves should be in series.

An SCV valve is going to provide you with a supply of fluid for whatever, a cyl, hyd motor, etc, but in a logical order.
The SCV could be the 2ed or 3ed valve in series, and will have to take turns using the fluid.

An SCV can handle the high pressure, but does not have a relief valve. The SCV is either off or full on.

Any other valve upstream will have priority. If the FEL is using half of the flow, then the other half is available to the SCV.

An SCV should be mounted after the FEL valve so the FEL relief will provide some protection.

As far as using the SCV to run a T-N-T , as I said before, the SCV is either off or full on, no feathering.

 

[Attono]

Thanks very much, J J. But how does an SCV which is controlled with a mechanical lever provide an oil supply to a backhoe?

 

[CinderSchnauzer]

Thanks very much, J J. But how does an SCV which is controlled with a mechanical lever provide an oil supply to a backhoe?

You have to hold it open with a bungee cord. It is a PITA.
BTDT. Get Power Beyond.

 

[J_J]

SCV = Secondary Control Valve

Solenoid Control Valve

Selective Control Valve

Which do you have?

Does your valve have a solenoid attached to it, or is it lever controlled?

Excerpt:

Using Third SCV Momentary Switch
The third SCV may be operated in a momentary condition to operate attachments such as extending or retracting a cylinder or short use of a hydraulic motor. This is a direct acting on/off circuit. The attachment will receive full hydraulic flow in direct response to the use of the switch.

 

[Attono]

They are lever controlled.