I am retrofitting the backhoe from a Case 860 to my Jet Star. This backhoe uses hydraulics from the tractor.

My Jet Star has the optional hydraulic pump on the PTO. So the first question is which hydraulic system do I use? The PTO pump does not seem to be rated in flow, but is obviously larger and presumably higher in flow than the standard pump. However it has no reservoir, so I can only use the backhoe if my front-end loader is attached (which does have a reservoir) or I make one for the hoe.
The standard pump obviously has a reservoir but none of my MM manuals state how large it is so the oil volume of the hoe cylinders may be too great. Anyone know the capacity of the Jet Star?

The second question is pressure. The hoe is designed to take 2500 psi and my Jet Star is specked for 1500 psi. Is the pressure regulated to protect the tractor or the implements? can I just crank up the pressure to 2500 psi without abusing the tractor?

Should be you, won't be using more than one valve at the same instant. And all the cyl s are double acting.

MMDEL

Yes, the reservoir for my loader is in the frame. I am rerouting the hydraulics for the hoe from the tractor to the PTO pump and loader. Actually I doubt that the loader's reservoir will be adequate for both, but I will find out. I will mount a 2nd reservoir on the hoe if necessary, or if I want to use it when the loader is removed. If I buy two more Jet Stars I can dedicate one to the loader, one to the hoe, and one for the blade!

If there is only 2 gal. in the standard reservoir you are certainly correct. The 7 cylinders on the hoe can certainly exceed that so a separate reservoir will be required.

The MM manuals explain how to adjust pressure on the standard pump. Will I break anything in the tractor if I crank up the pressure?

I have not found pressure regulation on the PTO pump, in the MM manuals or on the pump. I will install a pressure gage to see were it goes under load...

Do you know if a regulator exists, and if so where it is?

You will only achieve 1500 on a good pump. MM's don't have the rpm. Most require volume not pressure. Have backhoe with loader on same basic tractor. Reservoir in loader frame.

I wish I had seen this post first.

I am thinking you need a dedicated reservoir for you backhoe. And you may need a better/different pump capable of producing enough pressure to satisfy your backhoe.