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?