B7100 3 point wont lift

[mainer0311]

I bought my first tractor this fall to help with projects around my newly purchased house. The tractor is a 1981 B7100 with ~950 hours on it.

I use it to move split fire wood from my garage to my house. Wednesday morning I went about it as I normally do. Started it and tried to lift the counter weight (about 500lbs), it wouldn't move. I took the counter weight off and the 3 point still wouldn't go up. I could lift it by hand but it wouldn't stay up. Lifting it up slowly by hand and holding the lever in the lift position it feels as if it is ratcheting up under my power. At the top I let go and it falls back down.

The FEL works off of a different hyd pump and works as it should. Wednesday morning it was between 5° and 10° F. I pulled the dip stick on the transmission and it had plenty of very thick oil. I engaged the PTO and let it run at idle to try and warm up some of the oil with no help to the 3 point.

I attempted to lift the 3 point today at 25° F and it wouldn't move under hydraulic power.

The diverter valve is impossible to turn by hand and I didn't want to break something with a set of channel locks, I don't believe it is positioned incorrectly.

Any suggestions on where to check next? I've been meaning to do a full oil change but am waiting for warmer weather.

Cooper

 

[Egon]

Look at the control lever and linkage?

 

[mainer0311]

From what I see the control lever goes directly into the top of the transmission. There is a rod attached to it with a linkage to the 3 point lift arm. It looks like a stop for when it lifts all the way up. the linkage isn't limiting movement of the control lever in anyway. The control lever feels like it is moving without any resistance.

 

[KubotainNH]

You may want to check the filter built into the bolt that goes through the rear banjo fitting under the seat. There's also a relief valve built into the control valve, maybe it's stuck open. I had that happen on my loader valve. Attached are some pics from a manual from another model that shares most things.

 

[KubotainNH]

Hmm, that uploaded strangely but the 2 pages are there.

 

[mainer0311]

When the 3 point was working you could hear the relief valve lift when the arms reached the top. I'm not hearing that sound now. I will check the filter.

Cooper

 

[Egon]

On the diagram I was thinking about the interlock holder.

 

[Baby Grand]

Can you hear any change when you put the 3 point lift lever in lift position?
Our similar b5100 makes a lot of flow noise when you operate the 3pt lift.
Just trying to figure out if the valve body is moving.
If it's not making any flow noise, then I'd suspect the valve body isn't moving: linkage malfunction.
If it is making noise, then I'd suspect either the lift cylinder seal is gone, or the relief valve is stuck open.
Maybe JJ is around to comment?

 

[Thomas]

Do you have hyd. direction valve,check to see if fully open etc.

 

[mainer0311]

There is no noise when the lever is moved. When you say linkage is there an internal linkage or is the lever the linkage you speak of.

Do you mean the valve under the seat that directs between the THP and what ever is tied into the other port. If so that is in the correct direction.