Please forgive me. I know this has been discussed before and I've read through other threads but I can't seem to find the good ones that I thought I saved at some point. I've been building this setup for a couple years on and off.
I built a homemade loader for my Case 444 that uses two lift cylinders and one bucket-tilt cylinder. My tractor is setup with the factory TCV, a J-17 PTO on the back, and the joystick spool that I installed for the loader.
The loader spool has a float setting for the lift cylinders, rapid-extend for the bucket tilt cylinder, and a power beyond fitting.
I currently do not have the power beyond fitting installed. When I first setup the spool, I had the PB fitting installed but it was dead-heading the system as soon as I tried using either of the circuits on the spool. It currently works without the PB fitting installed but with a couple issues that I'm hoping to resolve. I may have things hooked up in the wrong series or it's due to not having a PB fitting installed. I'm not sure, so let me know what you think.....
When trying to use the float setting as the tractor is travelling forward or backward, the cylinders slowly extend, rather than acting static. I'm not sure if this is a high pressure issue due to the way I've plumbed everything or if it's because I'm not using some sort of power beyond setup.
Also, the rapid-extend setting just seems to "overload" the system and actually causes the bucket-tilt cylinder to reverse direction.
Right now, everything is plumbed in this sequence. Attached is a quick drawing that may help convey my current design.
2: Loader Spool
3: J-17 PTO
5: Oil Tank
Your float setting will not work with any backpressure [which the travel motor will create] and a rapid dump feature needs a large return directly to the tank to work properly. That is why loader tractors use a separate pump and circuit or a flow divider to allow 2 circuits with no downstream restrictions.
Well, you're sending 2500 PSi oil at 8 - 10 GPM to a system, the loader that, should be running 1500 psi and 4 - 6 gpm.
The hydraulics need to be plumbed in order of highest pressure and volume to lowest pressure and volume. In the 600 loaders, its Pump to PTO to TCV to loader. Many 400 owners that insist on putting loaders on their tractors take their loaders hydraulic supply from the TCV's mid lift - pto circuit.
Power beyond fittings are not quite creating a separate hydraulic circuit. What they do is any oil not used by the valves is routed to the PB. While any oil used by the valves goes out the valves return - tank port. Which is why the oil supply at a PB can be extremely variable. But the PB is also a direct feed from the pump when the valves are not in use. In the design of the CCI TCV the main relief valve is in the circuit before the PB, not sure how your valve is setup:
The power beyond fitting your talking about sounds like a open-center / closed center convertor. Power beyond will have a port in the fitting that you use for the rest of the circuit (which is the power beyond). The control valve will have to have a connection to tank. Once you correct this, your problems should be solved. But tell us how it works. Also, post pictures of your control valve installation, and the valve tag.