Hydraulic Problem on MF 1759

[MarkGrabb]

Hello All - For the first time after owning the tractor for 7 years... I bought an implement that required hydraulic hookup. I planned to use the hydraulic connections for the two hydraulic lines from the implement at the front for the curl of the front loader. I took off the top quick connect by mistake (which happened to be the "up" hydraulic for the up and down of the loader.) I took off the bottom two hydraulic lines to connect the hydraulics from the implement... but I couldn't get the top quick connector to connect back in. I relived the pressure from the loader by jiggling the joystick with the key off... and I removed the pressure from the connector by wrapping it in a rag and tapping it.... but it still won't connect. My curl works on the front loader (I have both lines securely connected). However, neither my up nor down works on the front loader. I have the down hydraulic securely connected, but it still doesn't work. The up hydraulic won't connect.... so I am less surprised that the up doesn't work. I added some hydraulic fluid. When I curl the front loader... the bucket stays suspended in the air.. so I assuming it is holding pressure.
1) Do I have to have both the up and down hydraulic lines connected for up and down to work? 2) Could I have gotten air in the system... and if so.. how would I bleed it? I am used to working on cars... but I am at a loss when it comes to working on tractors. Any clues you can provide will be greatly appreciated, Or if there is something I should try... I can do that and report back. I have twenty acres of straw that was combined by a friend for the seeds... but now I need to cut the remainder and get it baled before if goes bad... so I really appreciate any insights.

 

[oldnslo]

Yes you need both lines connected to the lift lower cylinders for them to operate. Oil goes into cylinders in one line and of of the other end of cylinder via the other. You may have to support the loader bucket to remove any load induced pressure to be able to connect the lines. Typically any trapped pressure makes it very difficult or impossible to connect the quick disconnects.

 

[lpakiz]

Yep, old has it right! Prop something like a piece of 2X4 about the right height under the bucket. You might be able to roll the bucket forward a few inches to take the weight off the loader. That will allow the ball check in the coupler to be moved off of its seat. You can verify whether the ball is releasing by depressing it with a 3" piece of 1/2 wood dowel, a 1/2" steel rod, anything to reach into the coupler and depress the ball. CAUTION--wrap a rag around this assembly as you attempt to depress the ball. There can be "some" pressure present, which will invariably squirt you in the face, glasses or on your clean shirt.
When the ball on the male tip and the ball in the female coupler can be depressed by firm hand pressure, the coupler is ready to be connected. But you won't be able to depress the ball if there is pressure present, such as pressure being generated from gravity. Propping up and supporting the bucket will relieve this pressure.
If you can't depress both coupler balls, you will not be able to connect the quick-coupler.

 

[MarkGrabb]

Yes you need both lines connected to the lift lower cylinders for them to operate. Oil goes into cylinders in one line and of of the other end of cylinder via the other. You may have to support the loader bucket to remove any load induced pressure to be able to connect the lines. Typically any trapped pressure makes it very difficult or impossible to connect the quick disconnects.

Many thanks! It worked!

 

[MarkGrabb]

Yep, old has it right! Prop something like a piece of 2X4 about the right height under the bucket. You might be able to roll the bucket forward a few inches to take the weight off the loader. That will allow the ball check in the coupler to be moved off of its seat. You can verify whether the ball is releasing by depressing it with a 3" piece of 1/2 wood dowel, a 1/2" steel rod, anything to reach into the coupler and depress the ball. CAUTION--wrap a rag around this assembly as you attempt to depress the ball. There can be "some" pressure present, which will invariably squirt you in the face, glasses or on your clean shirt.
When the ball on the male tip and the ball in the female coupler can be depressed by firm hand pressure, the coupler is ready to be connected. But you won't be able to depress the ball if there is pressure present, such as pressure being generated from gravity. Propping up and supporting the bucket will relieve this pressure.
If you can't depress both coupler balls, you will not be able to connect the quick-coupler.

Many thanks! It worked. The 2x4 wood trick worked well. I used the rag.. yet the pressure was clearly off this time when I depressed the male end. The quick connect worked smoothly with one try. I really appreciate the quick advice from you and Old. Up & Running again!

 

[lpakiz]

 

[oldnslo]

Thanks for letting us know what the solution to your problem was.