B26 3 Point Hitch Broken?

[BAP]

A couple of us have pointed out the speed control knob under the seat. Have you actually checked it out? You have not answered that question.

 

[#40Fan]

I'd go after the safety valve first. You should be able to remove it and confirm flow when you move the 3pt lever. Likely be a mess, so be prepared.

If you have flow, I'd think the piston would move.

Pull the entire valve (circled) and not the end screw (X).

 

[Smokeydog]

Get a owners, WSM and parts manual. Got mine off eBay. The B26 and other TLB series tractors are different from their ag brothers.

We run our B26 90% in 3pt mode. When trouble shooting check the easy stuff first. I suspect you would save money by having the dealer check and diagnose. Experience is your friend. Surprised you didn’t ask when you picked up your hydraulic oil.

Love our little B26. Wife thinks it’s hers. They do have an inherit problem with the hydraulic suction line el rubber boot cracking and sucking air. New design line helps fix the problem.

 

[TheOldHokie]

I'd go after the safety valve first. You should be able to remove it and confirm flow when you move the 3pt lever. Likely be a mess, so be prepared.

If you have flow, I'd think the piston would move.

Pull the entire valve (circled) and not the end screw (X).

I like that . Messy but it should resolve the question of position control valve opening or not. That of course presumes the valve is actually getting flow.....

Dan

 

[GreensvilleJay]

When he said 'ZERO resistance', I think the arms can easily 'flop' up and down freely, as in NO mechancical connection to the ram in the cylinder. If still connected there should be some 'stiction', friction, drag, resistance to moving the arms even if the seals are damaged.

 

[TheOldHokie]

When he said 'ZERO resistance', I think the arms can easily 'flop' up and down freely, as in NO mechancical connection to the ram in the cylinder. If still connected there should be some 'stiction', friction, drag, resistance to moving the arms even if the seals are damaged.

I dont think the push rod is connected to the piston - just the rockshaft.

Dan

 

[GreensvilleJay]

hmm, interesting...looked at the online dwg, there's a pin for the rod to connect to the rockshaft but none for the piston end ! ( I'd assumed it was connected.... )
so... the piston is probably at the top of the cylinder and no oil is being allowed to push the piston down...sounds like a 'hydraulic flow' problem not a menchanical one.
I have to assume there's some kind of design to automatically align the push rod into the piston and not score the wall of the cylinder ?

 

[North Idaho Wolfman]

hmm, interesting...looked at the online dwg, there's a pin for the rod to connect to the rockshaft but none for the piston end ! ( I'd assumed it was connected.... )
so... the piston is probably at the top of the cylinder and no oil is being allowed to push the piston down...sounds like a 'hydraulic flow' problem not a menchanical one.
I have to assume there's some kind of design to automatically align the push rod into the piston and not score the wall of the cylinder ?

The backside of the piston is a cup, and the front side of the rod is a ball.
there is a "keeper" that keeps the rod from falling to far down if the three point is lifted without the piston being down.

 

[TheOldHokie]

The backside of the piston is a cup, and the front side of the rod is a ball.
there is a "keeper" that keeps the rod from falling to far down if the three point is lifted without the piston being down.

Very common (standard??) design.
The rod on old Fords had a double ball end - AKA the lift dog bone.

Dan

 

[GreensvilleJay]

so ....you should feel some 'resistance' if you move the arms ? not 'ZERO' ??

 

[North Idaho Wolfman]

so ....you should feel some 'resistance' if you move the arms ? not 'ZERO' ??

Nope you'll feel no resistance at all, at least nothing the normal human body could tell.
When you lift the arms the connecting rod is touching nothing, well maybe sliding down the sides of the piston center.
Your not pulling down on the piston when you move the arms.

 

[kubotamilt]

So I looked through the wsm today. From the troubleshooting chart, it looks like I have a control valve problem.

as far as the drop speed control knob goes, I have adjusted it, but it should have no effect on the lift arms going up.

I will look into the safety valve on my way into the three point cylinder housing. It looks like it too is under the seat. According to the wsm, this valve just helps reduce shock from implements bouncing around to prevent damage to the cylinder. Are you thinking that this valve may have failed in the open position so that fluid is just passing by without moving the lift cylinder?

 

[#40Fan]

So I looked through the wsm today. From the troubleshooting chart, it looks like I have a control valve problem.

as far as the drop speed control knob goes, I have adjusted it, but it should have no effect on the lift arms going up.

I will look into the safety valve on my way into the three point cylinder housing. It looks like it too is under the seat. According to the wsm, this valve just helps reduce shock from implements bouncing around to prevent damage to the cylinder. Are you thinking that this valve may have failed in the open position so that fluid is just passing by without moving the lift cylinder?

I don't think the safety valve could keep all fluid from making it to the piston, but pulling it out and moving the 3pt lever would let you know if there is a flow issue. If everything is working like it should, it will squirt fluid out with the valve removed.

 

[TheOldHokie]

I don't think the safety valve could keep all fluid from making it to the piston, but pulling it out and moving the 3pt lever would let you know if there is a flow issue. If everything is working like it should, it will squirt fluid out with the valve removed.

Plus one - the safety vslve cavity is a easy to access test point.. Removing the safety valve will let you monitor oil flow into the lift circuit.

Start the tractor with position control lever in full down position. When you raise the lever oil should start to flow and will continue until you move the lever back down. No flow indicates a defective control valve/linkage or a problem with the oil supply to the valve.

A length of vinyl tube jammed into the open port may help you catch the oil and reduce the mess.

Dan

 

[Chanceywd]

Very common (standard??) design.
The rod on old Fords had a double ball end - AKA the lift dog bone.

Dan

View attachment 94249

The 8N dog bone doesn't fall out of place for sure. I added an external cylinder to my 8n so I could raise my 3pt when stopped with out having to shift to neutral I leave the 3pt lever down to use it. When I don't need it I take the cylinder off and put the 8n pump in gear and use the internal one.

 

[kubotamilt]

Okay, so if I understand correctly, remove safety valve - If oil flows out when raising the three point, I have a bad cylinder seal. If oil does not flow out of it, then I have a bad control valve.

makes sense!

 

[TheOldHokie]

Okay, so if I understand correctly, remove safety valve - If oil flows out when raising the three point, I have a bad cylinder seal. If oil does not flow out of it, then I have a bad control valve.

makes sense!

If oil flows out you have a working control valve and oil supply circuit. In that case my next test would be a pressure test at that same port

If no oil flows out you have a malfunctioning control valve, a linkage problem, and/or no oil supply.

Dan

 

[kubotamilt]

Hey everyone, just wanting to Keep people in the loop. Sorry for taking so long, but life gets in the way! I took the safety valve out…no oil… so in we go!

 

[#40Fan]

That's a bummer.

Give it a good bath beforehand. Don't want to risk getting any dirt inside.

 

[kubotamilt]

So I tore into things last night. It turns out that the feedback linkage was the issue. There is a little tab that connects to the feedback linkage to the control valve inside the case, and that was not connected. Once everything was opened up, it was a really easy fix. Im not sure how this could have happened though. Nothing was broken, the tab was just not in the right place. I saw some evidence of someone else having taken things apart as well (bought it used), so I am thinking that they reassembled it incorrectly.

Anyway, the tractor is back together and the three point works great! Thanks for all the help!

Though it's not likely, if anyone else has this problem, you can tell by moving the feedback linkage. If there is no resistance, it is not connected to the control valve. You should be able to feel some spring force on the feedback linkage.

If you are thinking about doing this job for any reason, its not that bad. It doesn't require any special tools, but it does require some patience. Theres quite a few linkages for everything running around under the seat, so it take some time to gain access to the lift arm housing. Ratcheting wrenches are a MUST! Overall though, I would consider this and intermediate job. No measuring, and no precision parts are needed, unless you need to get inside the control valve. I also tested the control valve by very carefully using compressed air to actuate the cylinder. This was very helpful, since I wasn't sure if there was multiple problems. When you're that far in, you want to know that things are working properly before reassembling.

Hope this helps in case anyone in the future has the same problems.