B7800 MMM slow to raise/lower

[dmnsmith2]

Wanted to ask what I can look for in solving the problem of my mid mount mower raising and lowering slowly on my B7800. The quarter inching settings are not working at all. I usually have to move the controller up and down several times to get the mower to raise or lower. Thanks in advance!

 

[thetooth]

Have you adjusted the valve right below the front of the seat there is a knob for adjusting how fast/slow the implements lower .

 

[BrierPatch]

I would check the linkage or connection from the handle to the valve. Sounds like it might be loose or sloppy. When you say the 1/4" doesn't work, do you mean it doesn't move or doesn't move the right amount. The 1/4" movement is an adjustable stop in the lever guide. Can you move your raise and lower handle around the 1/4" stop to get the deck to raise and lower okay. At least this is the way my B2620 is, I also have an adjustable stop for raise and lower that is connceted to the 3pt lift arm on the right side.

 

[dmnsmith2]

Yes I have adjusted the open/close dial below the seat. When this is all the way open it will lower quickly, like it should, but doesn not help with the lifting upwards of the deck. The 1/4" settings do not work at all. I have to move the lever all the way down/up several times to get the deck to go down/up.

 

[bigdad]

How's your hydro Fluid?

 

[BrierPatch]

Can you still feel the center detent on the valve with the handle? Does it still seem like it is centered in the handle movement range or do you feel the detent when the handle is almost all the way up or down? Will the raise/lower handle stay in the center position? Can you hear fluid flowing when you try to raise or lower and nothing happens? I am leaning towards a valve problem or handle connection to the valve.

 

[jonsstihl]

I had that same problem with mine when I bought it and it turned out to be the connection between the valve and the linkage, I believe the technical term is the feedback linkage.

there is a rod that slides through a bolt with a hole in it and there is also a spring on the rod. mine was rusted up and the rod was no longer sliding so what happened was when I lifted the handle this feedback linkage that was seized was telling the machine that the 3ph was at the top of its stroke even when it was at the bottom.

this feedback linkage is located under the seat on the right side of the tractor. have someone move the lever while you watch and you should be able to see what i'm talking about. I believe there is a snap ring to hold the linkage together. I took it all apart and use sandpaper to clean it up and greased it well before putting it back together and it has been working fine since.

hope that helps. I will try to get a picture up so you can find it easier tonight

 

[dmnsmith2]

The fluid level is fine. Also the handle will stay in the center position and absolutely can hear fluid movement when I am trying to move the deck.


James, I will check this when I get home tonight. A picture would be awesome!

Thanks for all input!!

 

[jonsstihl]

sorry it took so long but here are some pics hope that is the problem because it is an easy fix


there is a snap ring on the inside of the 3pt lift arm. the problem with mine was not that it would not slide on the rod, the real problem was that the fitting was not rotating in the 3pt lift arm so it was binding on the rod.

I don't think I had to touch the bolts and spring I just pulled the snap ring and pulled the fitting off the arm with pliers and greased the part that goes inside the 3pt lift arm

if you do have to touch the bolts make sure it is properly adjusted, this feedback linkage controls how far the 3pt lifts and is adjusted so that there is still some freeplay in the arms after they reach the top. If there is no more freeplay the cylinder is bottomed out and it may damage it.

hope that helps and again sorry for it being so long but better late than never

 

[BrierPatch]

Have you tried your 3pt with nothing connected to it in case it might be the mower deck that is binding. I would dissconnect the connecting rods (that sounds a little funny) the rods that go from the upper lifting arms to the lower drag arms of your 3pt. This way there would be nothing connected to your 3pt lifting arms and see if they still have a problem moving. If you can hear fluid flowing with no movement, I would start to wonder about the 3pt lifting cyclinder itself, but somebody with a better understanding might be of more help on that.

Hope things are going well for you.:thumbsup: