Checking MF52 backhoe hydraulic pressure

I recently installed a MF52 backhoe to my MF34 Front loader on my MF40 Industrial. I want to make sure the backhoe is getting adequate hydraulic pressure. Do I perform this pressure test from the control valve test port on the front loader or somewhere on the backhoe? If from the front loader, do I check the pressure from the test port with each valve extreme on the backhoe?

I think it is likely you have a main relief in both valves. The service manuals for each, the hoe and the loader, should have the procedures to check each and the set pressures.

(quoted from post at 17:10:46 01/05/20)
I think it is likely you have a main relief in both valves. The service manuals for each, the hoe and the loader, should have the procedures to check each and the set pressures.

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I would think so also. The service manual says that the backhoe pressure is serviced from the loader control valve. I understand how to check the main relief valve by forcing the lift cylinders to each stroke extreme. Would I force the boom cylinder to both stroke extremes to test the pressure at the backhoe?

Also, since I am not close to my tractor I am needing to make sure I bring the correct tools and fittings. What is the plug size of the control valve test port to hook up the hydraulic pressure gauge?

If the manual says the hoe pressure is serviced from the loader relief valve, you should see the same pressure if you check a loader function as a boom function. Set it using the loader boom then see what you have when you use the hoe boom. Forcing any cylinder to its extreme will cause the main relief to work. A couple clarifications to that are as long as it doesn't have another bypass relief and the cylinder packings are not worn and letting oil by them.

Sorry I can't tell you the size, or thread type, of the plug is.

(quoted from post at 10:35:42 01/07/20) If the manual says the hoe pressure is serviced from the loader relief valve, you should see the same pressure if you check a loader function as a boom function. Set it using the loader boom then see what you have when you use the hoe boom. Forcing any cylinder to its extreme will cause the main relief to work. A couple clarifications to that are as long as it doesn't have another bypass relief and the cylinder packings are not worn and letting oil by them.

Sorry I can't tell you the size, or thread type, of the plug is.

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I was able to adjust the main relief valve on the front loader that provided pressure to the Front Loader and the Backhoe. It was set at 1500psi, so I increased the pressure to 2500psi based on the instructions in the manual. My Backhoe seems to have poor pressure in the rotary cylinder and swings when in neutral. I plan to go through the swing test procedures to determine if the circuit relief valves are bad or the anti-cavitation poppets. According to the manual it looks like the circuit relief valves are adjustable and can be taken apart and cleaned. I am hoping that will fix the swinging. Agco Parts lists the part numbers to the valves to be 1089467M91, however I can't find them online. Where can I find the part or one that will work?

The manual states in section 7 to test the circuit reliefs within the swing cylinder to check their pressure settings. Looks like I am to connect a 3000psi pressure gauge to both ports on both sides of the cylinder at the same time. I assume the test ports are the same ports where the circuit relief valves are removed from? Also in section 7-b it states to swing the backhoe in both directions until the reliefs blow and record the maximum pressure. How do I know when the reliefs blow?

I don't know what kind of luck you will have finding parts for the rotary cylinder. Have you talked to a MF/AGCO dealer and see if they still have them? I know some people have converted the Henry and MFs with rotary swing to regular cylinders for swing.

I have to think the circuit relief valves need to be in place to test them, unless you have the special tooling they mention to do them out of the machine. It is hard to read in the photo but I believe 7a says "With the system returned to normal operating condition, connect a 3000 psi gauge into the test ports at both sides of the cylinder." That says to me; back together ready to run. In the parts book it shows 1/8 NPT plugs in the sides of the barrel of one of the rotary swing cylinders (They apparently used two different ones.) which may be the test ports. I would expect to find similar ports some where in the other cylinder as well.

You say you adjusted the main relief to 2500 psi. # 7 Conclusion: gives pressure setting for the two different valves they used. Looks like one style is set at 2150 psi and the other style is 1875 psi. So if they are working right when you reach the end of the swing travel they will release at one pressure or the other, depending on which valves you have. You will not be able to achieve the 2500 psi the main is set for. If the gauge reads much below or above either of those pressures the circuit relief needs adjusting or replacement.

Best I can tell you from the info. I don't know for certain hopefully someone will be along with more info for you.