Loader Hydraulics

[smallfarm]

I now have my Wagner loader and fast hitch on my 62 cub. The modifications to the fast hitch are basically that I raised the depth control 3 inches and moved it forward a bit to clear everything. This requires moving the attachment point on the bail up 3 inches and forward 5 inches. This reduces the vertical movement of the bell about 25% but both the plow and disk work with the remaining available adjustment

While testing the plow and disk motion I took the loader for a trial run the trip bucket latch will need some bending back from the loader having taken a hit, sometime in the past. Before I get to all of that, I plan on addressing the hydraulic system. I plugged it back the way it was when removed.

Figure A is the current set up. As expected, this gives the touch control a mind of its own when using the loader , what I did not anticipate is pumping oil out of the reservoir breather. To prevent this a gate valve on the line from the pump to the loader, control valve must be closed unless loader is being raised and closed as soon as the upward motion stops. Needless to say this is pretty awkward.

Figure B is how I believe the hydraulics should be connected. It will involve a fair amount of pipe plumbing, (and un-plumbing) but only one more hose. Prior to committing to this I have a concern. I see no indication of a pressure relief valve on my loader control. The only place it could be is under the cap where the spool valve would be removed. I am not an hydraulics expert, but have never seen a valve like that. I know I could tear it apart and look, but as of late— everything I have tried to inspect ends up broken.

1). If there is indeed, no pressure relief valve will the pump output deadhead into the control valve?

2). If so, how much damage for that do in the minute the tractor takes to warm up enough to test run the hydraulics

3). Can an external in-line pressure relief valve be added between the supply line to the loader control valve and the pressure return to the bypass block.

Thanks to all

[CharlieK]

good luck to ya

[ajhbike]

I just took a loader off a cub...homemade job and I believe it was rigged up like A. Is it possible that you simply have too much oil in the system?

[radioguy41]

Does this help? Since yours is a trip bucket you can ignore the red lines, they're for a bucket cylinder.

Click on image for a larger view.

[smallfarm]

[quote="radioguy41"]Does this help? Since yours is a trip bucket you can ignore the red lines, they're for a bucket cylinder.

I appreciate the input however, the drawing does not apply to my situation. My control valve has only three ports. The drawing shown without the red lines still has four. Hydraulic line from the pump. An hydraulic line to the bypass block. A line to the bucket lift arm. The fourth line, connects to both the reservoir and the farmall cub hydraulic cylinder block. My control valve has only three ports. My current set up has an hydraulic input. A line to the bucket lift arm cylinders, and a third, connecting to the reservoir on the loader and the Farmall hydraulic cylinder block.

Perhaps another question should be; does the connection from the valve spool assembly that connects to the reservoir, and Farmall hydraulic cylinder block apply only two loaders with two ways cylinders.

If so, the drawing you presented is otherwise very similar to my sketch “B”.

[radioguy41]

OK, how about this one from the Wagner manual?

Click on image for a larger view.

[smallfarm]

[quote="radioguy41"]OK, how about this one from the Wagner manual?

That is from the Wagner WM 1 or Wagner 45 manual. My loader is a W1. The plumbing shown is identical to my sketch “B”. The issue with going this route is that I see no external indication of a pressure relief valve on my spool valve assembly. These are shown as parts 17 through 23 in the Wagner manual section on the valve. (As a sidenote, there are several errors on that page of the manual. The parts list goes to 22, but the drawing goes to 23 and the O-ring And caps crew part six and four are also wrong.) My valve has a significantly different outside appearance than shown in the manual. Perhaps Wagner supplied the earliest loaders for installation on tractors with a pump but without a touch control? Another possibility is that the pressure relief is inside the valve but, in my limited experience, I’ve never seen it a valve like that.
The current (annoying) setup gives the pressure leaving the pump an either/ or / or option— loader in lift action or touch control in motion or farmall pressure relief.

I’m not sure I want to change the plumbing to match the drawings and “fire ‘er up to see” without KNOWING there is a properly adjusted relief valve. I guess the only option is to take the valve off and apart. If it has no pressure relief valve inside, it gets replaced with a modern one.

Tractor one, bad starter.
Tractor two, loader problems.
Riding mower, needs new drive belts

It’s spring!

[Jim Becker]

There is a lot to unpack here. First off, I think your figure A does not have a bypass block while figure B does. It isn't totally clear that is the case. The rest of my comments assume so. Also, from the picture of your valve, I am reasonably sure it has no pressure relief built in. If there is none, there MUST be a pressure relief somewhere in the line from the pump to the valve inlet. The pressure relief needs 3 lines. One from the pump, one to the valve, and one returning directly to a reservoir. If a valve has a built-in pressure relief, if is functionally the same as a separate relief valve with the third relief valve connection internally run to the outlet of the valve body. For that design to provide full protection, the valve outlet needs to go straight to the reservoir. If the flow through the valve needs to go on to provide another function, as in feeding the Touch-Control system, it should be a "power beyond" valve. That type valve will work properly even if the outflow is under pressure to operate a downstream function. It will send the relief flow to a separate connection that should not be under pressure, straight to the reservoir.

Figure A:
As drawn, it is trying to supply fluid under pressure to both the Touch-Control system and the loader valve. Naturally, the oil is going to take the path of least resistance. Any attempt to operate one system will push oil to the other system. Neither will work unless you try to operate both at once. Then the one with the least load will move. The way this type of connection is expected to be used is to disable the Touch-Control, normally by blocking the rockshaft in the rear position and moving the control lever forward. Thus causes the main Touch-Control unit to function only as a relief valve.

Figure B:
If the loader control valve does not have a built-in relief valve, do not do this. If the loader is lifted to the limit, or it tries to lift more than it is able to, the pump will be deadheaded. Damage from that can be extensive (and expensive). This can be avoided by adding a separate relief valve between the bypass block and the loader control valve. The relief line out of the relief valve needs to go directly to the reservoir. The second problem with this configuration is that you do not appear to have a power beyond valve. You are running the outflow from the valve to the Touch-Control system, which can put back pressure on the outflow. When that happens you can get strange behavior. For example, you are lowering the loader and move the Touch-Control lever back while the bucket is dropping. The back pressure will feed back to the loader cylinder and the loader will immediately jump up. This problem is avoided with a power beyond valve by having one line to pass pressure to the Touch-Control and a separate line to send return flow (and relief flow if there is a built-in relief) directly to the reservoir.

I could add comments on Radioguy's diagrams but think this is enough for now.

[smallfarm]

Jim
Thank you for your detailed reply. I, however, am not certain I fully understand what you said and have a sketch of what I think you mean. I would like to clarify that my sketch “A” had no bypass block and sketch “B” does. Furthermore, I am currently using the setup shown in sketch “A”. The hydraulics operate irregularly as expected. Besides that, oil is pushed into the reservoir faster than gravity permits it to return to the farmall hydraulic cylinder block.

Is the Northern Tools part shown appropriate?
Where can one access a stand alone power beyond setup?

[Jim Becker]

I wasn't clear on "power beyond". It is not a separate unit. It is a particular type of control valve. For your drawing to be correct, your "power beyond" and "control" need to be combined into one box with a total of 4 connections (as you have shown them). You can probably get along without a power beyond valve and it not behave too badly. I can elaborate on this, but not tonight.

The Prince relief valve would work okay. It can be adjusted to needed range (1,200 # or so) and handles more than enough flow for the Cub pump. You can probably find a control valve that is open center, built-in relief, and power beyond all in one unit. Then you would not need the separate pressure relief and have fewer hoses/connections. Somebody else on here may have already found such a valve.

Your problem with the reservoir spitting oil out has me baffled. Are you saying that it spits out the vent with the engine running even when not moving any of the hydraulic controls?

[smallfarm]

It’s been a while since I started all this. Again thanks (Jim in particular) for the input.

Removing the fill plug gave the following information.
The oil in the reservoir is about 1” below the fill line

At about 1/4 throttle the oil is pushed up to the top of the reservoir. Perhaps a bit overflows, but it doesn’t look too be enough to reach the weep hole. ( on this loader the weep hole breathes up the frame pipe and out by the left front tire)

When raising the dipper stick the reservoir level drops

When lowering the dipper stick significant oil comes out the reservoir fill hole.

It seems like the return line is insufficient to handle all the pump puts out. The loader came with a gate valve to turn off the flow to the loader control valve. Closing it forces the oil from the pump to the cylinder block. The touch control works normally when the valve is closed. To use the loader the gate valve is opened, the touch control is cycled then the loader used.
The bracket shown came with the loader and holds the rock shaft mid position. Seems to put a lot of pressure on it when the touch control does that “ mind of its own “ thing. I’m scared to use it.

Jim if you could please clarify what position you mean by “rock shaft in the rear position “ I would appreciate it.

[SamsFarm]

Whenever you get to hooking things up according to your figure B sketch from March 27 (also the diagram posted by radioguy41 » Wed Mar 29) I believe your problems will go away.

In pic #2 of your may 8 post, why does it look as your rock shaft is locked in place with that bar to the implement mounting boss on the torque tube?

Fyi:
A dipper stick is on a backhoe / trackhoe.
A loader has a boom.

[Jim Becker]

The loader came with a gate valve to turn off the flow to the loader control valve. Closing it forces the oil from the pump to the cylinder block. The touch control works normally when the valve is closed. To use the loader the gate valve is opened, the touch control is cycled then the loader used.
The bracket shown came with the loader and holds the rock shaft mid position. Seems to put a lot of pressure on it when the touch control does that “ mind of its own “ thing. I’m scared to use it.

Jim if you could please clarify what position you mean by “rock shaft in the rear position “ I would appreciate it.

That bracket looks like it was originally something else. By "rear position" I mean the rockshaft rotated towards the rear as it would normally be when the Touch-Control lever is moved fully to the rear. From the appearance in your picture, I think the bracket is holding it far enough toward the rear.

With that bracket in place, open the gate valve to allow flow to the loader control valve. Move the Touch-Control lever fully forward to block free flow through the Touch-Control unit. The loader should then work normally in response to the loader control valve.

Edit: I am assuming you still have it hooked up according to diagram A.

[smallfarm]

That bracket came with the loader and holds the rock shaft about midway. The bottom ( right) in the picture is a slot to allow it to be disconnected without totally unbolting it. I hesitate to use it because I need to close the gate valve to prevent oil loss. In theory it is ok but the one time I tried it there seemed to be considerable pressure on the bolt.

[Jim Becker]

It has to be used with the gate valve open. It is there to force fluid through the gate valve to the loader. If you lose oil, something else is wrong, including the possibility it is overfilled.

If by pressure on the bolt you mean there is a large strain on the bracket, yes. It can be under all the strain the Touch-Control is capable of exerting.