MF 275 auxillary hydraulic valve

[make n break]

When I try to use one of the 2 valves it locks up and won't function.
When I shut off the engine I can work the valve and it will move freely again.
Any thought on what might be causing this?
I notice there is a switch valve shown on the diagram in my manual but no explanation of what it does.
Would this need adjustment?
Would appreciate any help, thanks.

 

[namyessam]

When I try to use one of the 2 valves it locks up and won't function.
When I shut off the engine I can work the valve and it will move freely again.
Any thought on what might be causing this?
I notice there is a switch valve shown on the diagram in my manual but no explanation of what it does.
Would this need adjustment?
Would appreciate any help, thanks.

I'm not familiar with the 275 but looking at agcopartsbooks.com it appears the lift cover is similar in design or the same as on a 135 or 175. Is this valve mounted on the top of the lift cover in front of the seat?
First what type of auxiliary valve do you have one, two or three handle. Do you have any outlets coming out of the valve to the rear of the tractor? What are you trying to operate? What do you mean when you say it locks up. Is the switch valve you speak of on the front of the auxiliary valve? When I have this information, I will be able to help you. If you could post some pictures of the valve and hose on the tractor it would help. How long have you had the tractor?

namyessam

 

[make n break]

I'm not familiar with the 275 but looking at agcopartsbooks.com it appears the lift cover is similar in design or the same as on a 135 or 175. Is this valve mounted on the top of the lift cover in front of the seat?
First what type of auxiliary valve do you have one, two or three handle. Do you have any outlets coming out of the valve to the rear of the tractor? What are you trying to operate? What do you mean when you say it locks up. Is the switch valve you speak of on the front of the auxiliary valve? When I have this information, I will be able to help you. If you could post some pictures of the valve and hose on the tractor it would help. How long have you had the tractor?

namyessam

Thanks for your reply.
You are right, the lift cover is the same, and the double valve is located on top of the lift cover. The valves feed two remote couplers on the back of the tractor, they are currently used for a loader. One of the valves works fine, the other seems to build up pressure inside the valve, the oil isn't able to flow. I have switched the lines to see if the problem was further along in the hydraulic circuit but it is in the valve. The switch valve is on the front of the valve and is identified on the AGCO parts listing. If you are looking at AGCO parts it is the older series of MF 275. I got the tractor in November and have fixed the other problems but no luck with this on yet.

 

[namyessam]

Thanks for your reply.
You are right, the lift cover is the same, and the double valve is located on top of the lift cover. The valves feed two remote couplers on the back of the tractor, they are currently used for a loader. One of the valves works fine, the other seems to build up pressure inside the valve, the oil isn't able to flow. I have switched the lines to see if the problem was further along in the hydraulic circuit but it is in the valve. The switch valve is on the front of the valve and is identified on the AGCO parts listing. If you are looking at AGCO parts it is the older series of MF 275. I got the tractor in November and have fixed the other problems but no luck with this on yet.

Are your lift cylinders for the loader single acting or double acting (one hose at the barrel end or hose at both ends) do you have hydraulic dump on this loader or trip bucket? two hose coming of right hand side of valve? The draft lever on the right hand side of the seat needs to be pulled all the way back and the position lever needs to be pulled back to the constant pumping position. I'm sure you know this if you have the manual. The left hand auxiliary valve has to be pulled toward the seat to operate the three point, is this correct? The switch on the front of the valve needs to be screwed out for single acting cylinders and in for double acting cylinders. If you only have lift on the loader it should be hooked to the right hand side of the auxiliary valve and the left hand lever in the center position. I'll get back to this later since I'm at work on lunch right now. Post back.

 

[namyessam]

Are your lift cylinders for the loader single acting or double acting (one hose at the barrel end or hose at both ends) do you have hydraulic dump on this loader or trip bucket? two hose coming of right hand side of valve? The draft lever on the right hand side of the seat needs to be pulled all the way back and the position lever needs to be pulled back to the constant pumping position. I'm sure you know this if you have the manual. The left hand auxiliary valve has to be pulled toward the seat to operate the three point, is this correct? The switch on the front of the valve needs to be screwed out for single acting cylinders and in for double acting cylinders. If you only have lift on the loader it should be hooked to the right hand side of the auxiliary valve and the left hand lever in the center position. I'll get back to this later since I'm at work on lunch right now. Post back.

If you have single acting lift cylinders on the loader you will be using only one hose hooked to the cylinders. Hook this hose so that when you pull the right hand lever toward the seat the loader lifts. You must unscrew the switch valve on the right hand side of the valve. This allows oil from the pump to flow back to the tank that would otherwise go to the other side of the cylinder on a double acting cylinder when lowering the loader otherwise it will be blowing the relief valve.

I also had a single acting loader cylinders hooked to the right side of the auxiliary valve. When operating the right hand lever and the position lever is in constant pumping the left hand lever needs to be centered otherwise the three point will raise and lower every time you operate the loader with the right hand lever.

The following information is over and above what you have asked in your thread and is for your added information.

Another item is that to operate the three point with the left hand handle, you should have the draft lever pulled all the way back and the position lever in the constant pumping position. The switch valve on the left hand side must be screwed out. This is suppose to allow you to raise and lower the three point hitch with the left hand auxiliary lever. This will not give you constant position control though. The three point hitch will maintain a constant level when you operate it with the left hand auxiliary lever held back toward the seat and operate the three point with the position lever. This allows an infinite height positions for the three point that will be maintained by the hydraulic system while the engine is running and the pump is engaged. This feature has eluded me so far and I have just come across this information on this feature. I have not had the chance to try it out on my tractor. Right now the only way I operate my three point is to lock the left hand lever back and use the position lever to raise and lower the three point.

 

[make n break]

If you have single acting lift cylinders on the loader you will be using only one hose hooked to the cylinders. Hook this hose so that when you pull the right hand lever toward the seat the loader lifts. You must unscrew the switch valve on the right hand side of the valve. This allows oil from the pump to flow back to the tank that would otherwise go to the other side of the cylinder on a double acting cylinder when lowering the loader otherwise it will be blowing the relief valve.

I also had a single acting loader cylinders hooked to the right side of the auxiliary valve. When operating the right hand lever and the position lever is in constant pumping the left hand lever needs to be centered otherwise the three point will raise and lower every time you operate the loader with the right hand lever.

The following information is over and above what you have asked in your thread and is for your added information.

Another item is that to operate the three point with the left hand handle, you should have the draft lever pulled all the way back and the position lever in the constant pumping position. The switch valve on the left hand side must be screwed out. This is suppose to allow you to raise and lower the three point hitch with the left hand auxiliary lever. This will not give you constant position control though. The three point hitch will maintain a constant level when you operate it with the left hand auxiliary lever held back toward the seat and operate the three point with the position lever. This allows an infinite height positions for the three point that will be maintained by the hydraulic system while the engine is running and the pump is engaged. This feature has eluded me so far and I have just come across this information on this feature. I have not had the chance to try it out on my tractor. Right now the only way I operate my three point is to lock the left hand lever back and use the position lever to raise and lower the three point.

Thanks again, I have double acting cylinders. I checked the switch valves and they were both turned completely in, took the valve apart and no obvious problems there.
Oil is getting into both valves, but for some reason its not flowing through the one.

 

[namyessam]

Thanks again, I have double acting cylinders. I checked the switch valves and they were both turned completely in, took the valve apart and no obvious problems there.
Oil is getting into both valves, but for some reason its not flowing through the one.

So which valve is not operating properly and what is it doing?

 

[namyessam]

So which valve is not operating properly and what is it doing?

I'm still having a difficult time understanding your problem. You have the position lever in the constant pumping position, the draft lever pulled all the way back. You likey have a two stage clutch that cannot be depressed past the first stage or else the hydraulic pump will not run. You have double acting cylinders, the switch on the front of the valve is screwed in. I assume the loader is hooked to the right hand side of the valve. The left hand valve operates the three point. you cannot operate both the three point and the loader at the same time, either valve must be centered when operating the other. from what I have read the switch valve on the left hand side should be screwed out otherwise, I'm not sure why you say oil is not getting to one valve. what is happening or not happening that is causing your problem?
namyessam