3-Point Hitch MB265B 3 Point hitch will not raise

[stumpfield]

I got the equivalent of a 1533 (challenger MB265B). Never had a problem before. I parked the tractor for about a week. Now suddenly the 3 Point hitch will not raise. The front loader and all other hydraulic functions worked fine including the top and tilt. Any suggestion on where to look for potential problem? Thanks

 

[kthompson]

Do not know your tractor but does it have a valve under the seat to adjust the 3 pth? Many do. Is it possible someone played with it since you last used it and screw it in where the lift will not work?

 

[jeepcj7]

Not sure what set up you have, but it could just be a quick coupler hanging up.

 

[irvingj]

stumpfield- I thought for sure I broke something on my GC2310 when the 3PH wouldn't move, but kthompson's correct-- if that knob is screwed all the way in, the 3PH control won't do anything.

The knob's purpose is to control the speed at which the 3PH drops, with a "lock" position if it's screwed in (clockwise) all the way, like a faucet....

It's the knob on the left in the photo; the other one is for adjusting mower deck height. Maybe?

 

[stumpfield]

I have a similar knob. I turned it both directions but didn't make any difference. Today, I try it again then it suddenly works! I was able to raise the 3PH just once. After that it stop working again. I tried looking around to see if anything stuck but no luck. Any sugguestion on where to look specifically? Thanks.

stumpfield- I thought for sure I broke something on my GC2310 when the 3PH wouldn't move, but kthompson's correct-- if that knob is screwed all the way in, the 3PH control won't do anything.

The knob's purpose is to control the speed at which the 3PH drops, with a "lock" position if it's screwed in (clockwise) all the way, like a faucet....

It's the knob on the left in the photo; the other one is for adjusting mower deck height. Maybe?

 

[stumpfield]

There's a knob under the seat. I turned it back and forth but no help. I'm pretty sure no one plays with the tractor. It was working fine the last time I move the tractor. I have my boxblade on all the time so each time I move the tractor, I have to raise the 3PH.

Do not know your tractor but does it have a valve under the seat to adjust the 3 pth? Many do. Is it possible someone played with it since you last used it and screw it in where the lift will not work?

 

[irvingj]

Try turning knob counter-clockwise to open valve, leave it that way, then allow tractor to run for a while; perhaps there was not much fluid and/or pressure in the system? Maybe you opened the valve, some pressure/fluid got in, and then you closed it again which allowed it to work only a bit? I'm really just guessing here, but it seems to me that it took several minutes for stuff to start working again after I changed the hydraulic fuid, too.

 

[jhwentworth]

Here are some possible causes from the service manual for a MF 1433 (Agco ST35):
Lift does not rise.
Insufficient engine speed
Insuficient transmission oil
Air leak through suction piping
Clogged suction filter
Maladjusted relief valve
Stuck sequential valve spool
Broken control valve
Broken slow-return check valve

 

[stumpfield]

Anyone know if the 3PH uses the same fluid as the rest of the hydraulic system. My loader, top and tilt all seem to work fine. I was able to raise the boxscraper about an inch off the ground to move the tractor using the top/tilt. Should I go ahead and change the hydraulic filter and fluid to see if it helps? Thanks.

 

[irvingj]

stumpfield-- on my 2310 (with hydrostatic transmission), all hydraulic fluid is the same system- for drive, FEL, and 3PH; all the same except for front axle.... I'm running out of ideas, but jhwentworth's checklist sounds like a good way to go- all control linkages seem OK?

 

[jhwentworth]

Anyone know if the 3PH uses the same fluid as the rest of the hydraulic system. My loader, top and tilt all seem to work fine. I was able to raise the boxscraper about an inch off the ground to move the tractor using the top/tilt. Should I go ahead and change the hydraulic filter and fluid to see if it helps? Thanks.

FWIW: There's a block diagram of the hydraulic system in the service manual that shows the connections between system components. Considering the symptoms you described (tractor working properly, then a 1 week shut-down, now 3PH doesn't lift. All other hydraulics work OK) it doesn't seem likely that the problem is with the hydraulic power source. You mentioned a Top and Tilt; is this controlled by the auxiliary control valve? According to the block diagram the hydraulic pressure first goes through the auxiliary control valve before reaching the main control valve that operates the 3PH. Is this correct? If you raise the position lever and then move the auxiliary control valve is there any movement of the 3PH?

Are you able to manually lift the lift arms?

 

[JerryG]

You have one of two things wrong. A quick coupler isn't connected correctly. They can look like they are and not be. The other thing that it could be is one of your hydraulic levers. If one of the levers is not centering it can direct the flow so that the lift won't work. This can be the loader valve or the valve used for your T & T. Move these valves around and try the lift again. If this doesn't work, then take your quick couplers apart and reconnect them.

 

[stumpfield]

Yes. That's exactly the sympton. Top and Tilt is controlled by auxiliary control valve. After reading your post, I tried to raise the 3ph and move the Top/Tilt control at the same time. It works! Now I can raise and lower the 3ph with the position control lever. Not for long though. I can raise it up and down just a few times then it stops working again. If I just move either the Top or Tilt lever back and forth just slightly, then I can raise the 3ph again. If I keep moving it up and down and it will continue to work for as long as I keep raise and lower in a regular interval. If I stop and let it sit in either up or down position for a minute or so, it stops working. What do you think is wrong?

FWIW: There's a block diagram of the hydraulic system in the service manual that shows the connections between system components. Considering the symptoms you described (tractor working properly, then a 1 week shut-down, now 3PH doesn't lift. All other hydraulics work OK) it doesn't seem likely that the problem is with the hydraulic power source. You mentioned a Top and Tilt; is this controlled by the auxiliary control valve? According to the block diagram the hydraulic pressure first goes through the auxiliary control valve before reaching the main control valve that operates the 3PH. Is this correct? If you raise the position lever and then move the auxiliary control valve is there any movement of the 3PH?

Are you able to manually lift the lift arms?

 

[shutt40]

The problem is in the valve for your top/tilt. It could be that one of the spools is not going back to the center position and fluid is bypassing. try just moving one spool at a time and see when your 3pt starts working again. Or it could be your power beyond port in that valve. Try taking the line off that runs from the top/tilt valve to the 3pt and then remove the power beyond adapter and check the o-ring. If it doesn't have a power beyond adapter it could be that the back pressure has damaged the valve.
Frank

 

[jhwentworth]

Yes. That's exactly the sympton. Top and Tilt is controlled by auxiliary control valve. After reading your post, I tried to raise the 3ph and move the Top/Tilt control at the same time. It works! Now I can raise and lower the 3ph with the position control lever. Not for long though. I can raise it up and down just a few times then it stops working again. If I just move either the Top or Tilt lever back and forth just slightly, then I can raise the 3ph again. If I keep moving it up and down and it will continue to work for as long as I keep raise and lower in a regular interval. If I stop and let it sit in either up or down position for a minute or so, it stops working. What do you think is wrong?

First, what brand is the TnT and how long has it been installed on your tractor? Any chance there is warranty on the valve? The web site for the manufacturer of the TnT and/or the valve might have some troubleshooting help.

Second, I'd GUESS that if you opened the valve that there would be something fairly obviously wrong, but I'd make sure of the warranty status before opening.