Issues with Cub Hydraulics

ShawnAgne

ShawnAgne

501 Club
Having trouble with the hydraulics, here is what happened.
1. Before the snow came Saturday I was pulling a wagon and pure stupidity on my part maxed out the power angle and blew the gasket between the bypass block and the lines. Not the first time. Oil sprayed everywhere. Cut out a new one. Refilled the resevoir and cycled the main unit and the power angle multiple times to purge out the air.
2. Started the tractor up to plow snow Sunday morning (- below zero temps). Tractor started hydraulics worked just fine, then stopped. Nothing worked.
3. Today (Monday) applied the torpedo heater to the engine block for about 45 minutes then ran the tractor at high idle. Initially nothing but eventually started getting movement out of power angle. IT is slower than normal but will move. Sometimes a little faster but will move.
4. Applied more heat and let the engine run more. Tapped the block some and now the main arms will drop, but won't lift the blade. However if I put the lever in the correct position I can manually lift the blade and the hydraulics will hold.
5. When the motor runs faster that is when the main valve on the TC seems to want to function.

It appears since heat worked there i was some viscosity issue with the TSC hydraulic fluid (Hy Tran equiv). However It is still running slow and not lifting. So question is.
1. Is the screen plugged possibly from when the gasket blew? It was the top corner towards the front that blew off. Should I pull the TC and clean the screen?
2. Is it just a fluid contamination issue?
3. Could it be something with the pump?

Thanks in advance.
 
If you don't have a relief in your auxiliary valve, you need to add one. From your description it sounds like you don't have a relief in it. When you deadhead the cylinder, pressure will spike until something fails or the tractor stalls.

If the gasket was the weak point that failed, you're lucky, however I suspect further damage was likely done. The damage would be between the pump and your auxiliary valve since it's not protected by a relief valve. Anything beyond the auxiliary valve will be protected by the relief in the TC unit.

I'd suggest you pull the hydraulic pump and inspect it for damage. There could be a crack in the housing that's reducing the output pressure. Oil viscosity should have nothing to do with it.
 
ricky racer said:
If you don't have a relief in your auxiliary valve, you need to add one. From your description it sounds like you don't have a relief in it. When you deadhead the cylinder, pressure will spike until something fails or the tractor stalls.

If the gasket was the weak point that failed, you're lucky, however I suspect further damage was likely done. The damage would be between the pump and your auxiliary valve since it's not protected by a relief valve. Anything beyond the auxiliary valve will be protected by the relief in the TC unit.

I'd suggest you pull the hydraulic pump and inspect it for damage. There could be a crack in the housing that's reducing the output pressure. Oil viscosity should have nothing to do with it.
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Where would I look for a crack at? The pump itself isn't leaking from what I can tell.
As far as the relief valve what should I add and where?

Thanks for the reply.
 
I'm not sure where it might crack. You'll just have to pull it apart and give it a very good inspection. It could also be a failed o-ring as well. As I mentioned, the damage should be between the pump and your auxiliary valve if it there is no relief valve in your system. The pump is the most logical place I'd suspect to find a crack but the valve body I suppose could also be cracked. Anything down stream of the auxiliary valve should be protected by the relief in the TC unit. The auxiliary valve you're using doesn't have a built in relief in it?
From what you described it sounds like pressure from the pump is being diverted back into the return side of the pump and I'd assume that is either through a crack in the pump somewhere or the auxiliary valve body, or a damaged o-ring or other component in the pump assembly.
 
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I was out on Saturday plowing with mine when it was close 0 degrees out. I also run the TSC equivalent of Hy Tran. I let mine run for 5 minutes or so to let everything warm up before I tried the hydraulics. I first tried them immediately after startup and it made an ungodly noise so I let it warm up for a bit and it worked fine. Seemed to run alittle slower cause of the cold but not much. After it warmed up a bit more it worked just fine however I did completely rebuild my hydraulic reservoir and pump not but a couple months ago. So we had the same weather and this is just to give you an observation of how my Cub worked so you have something to compare to for functionality. Sounds like you might have damaged an O rings possible something else. All the knowledgeable guys on here help me do everything on mine. I also keep mine in an unheated garage with no supplement heat to warm the oil.
 
Running red that is exactly what happened but I didn't stop didn't dawn on me what was going on. 100 I let warm up.

The o rings that are being mentioned. Which ones?
 
My hydraulics function a little slower in the colder temps as well vs warmer temps.

If your hydraulic unit isn't functioning right and you've checked the basics (fluid level low, air in system, etc) then it might be time for a rebuild. There are rebuild kits you can buy that have all the parts you need in one kit. TM Tractor has a few kits depending on which block you have. It comes with o-rings, filter, and a few other parts you need to rebuild it. I rebuilt mine with a lot of help from folks at one of the Cubfests a couple years ago.
 
cdahl383 said:
My hydraulics function a little slower in the colder temps as well vs warmer temps.

If your hydraulic unit isn't functioning right and you've checked the basics (fluid level low, air in system, etc) then it might be time for a rebuild. There are rebuild kits you can buy that have all the parts you need in one kit. TM Tractor has a few kits depending on which block you have. It comes with o-rings, filter, and a few other parts you need to rebuild it. I rebuilt mine with a lot of help from folks at one of the Cubfests a couple years ago.
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Yeah the hydraulics were rebuilt by previous owner. Going to check the pump but also checking the screen. Been using AI and it's been having me problem solved and it's thinking there is crud in the strainer which is causing the slow movement after I heated up the tractor then let it run for an hour at fast idle. Called local IH dealer and got the o rings for the main piston and the head gasket. Have a complete rebuild kit coming also.

Going to wait till the weekend the pull the TC and check it out.
 
ShawnAgne said:
Yeah the hydraulics were rebuilt by previous owner. Going to check the pump but also checking the screen. Been using AI and it's been having me problem solved and it's thinking there is crud in the strainer which is causing the slow movement after I heated up the tractor then let it run for an hour at fast idle. Called local IH dealer and got the o rings for the main piston and the head gasket. Have a complete rebuild kit coming also.

Going to wait till the weekend the pull the TC and check it out.
Click to expand...
I think before you pull the TC unit, I'd pull the pump and auxiliary valve and give them a very thorough inspection. There's nothing wrong with rebuilding the TC unit but I doubt you'll find the problem there. You said that the gasket at your bypass block blew. The gasket material would have blown outward, not gotten sucked into the hydraulic line. If gasket material was sucked into the hydraulic line it would have to pass through the auxiliary valve before it ever got to the strainer screen and what little could possibly gotten to the screen certainly wouldn't plug it up. AI might be good for a lot of things but it's never repaired a Cub hydraulic malfunction, I'll bet.;) Also, are you 100% sure the new gasket is correct on the bypass block?
 
Kinda' sounds like it may have sheared the woodruff key in the drive gear of the pump. Just enough friction to pump a little oil with no resistance, stops when against any pressure. Had a similar situation many years ago on an MT John Deere.
 
My guess is a clogged screen.
When that gasket blew, it's really common for a little piece to get sucked in and plug up that intake screen. That would explain why the hydraulics are slow and weak, even after warming them up.
I'd definitely pull that TC unit and clean the screen before you look at anything else.
 
ricky racer said:
I think before you pull the TC unit, I'd pull the pump and auxiliary valve and give them a very thorough inspection. There's nothing wrong with rebuilding the TC unit but I doubt you'll find the problem there. You said that the gasket at your bypass block blew. The gasket material would have blown outward, not gotten sucked into the hydraulic line. If gasket material was sucked into the hydraulic line it would have to pass through the auxiliary valve before it ever got to the strainer screen and what little could possibly gotten to the screen certainly wouldn't plug it up. AI might be good for a lot of things but it's never repaired a Cub hydraulic malfunction, I'll bet.;) Also, are you 100% sure the new gasket is correct on the bypass block?
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Yeah because I've put them on before. Cut this one out from the original I had. And placed it on the same way.
 
Whatever you find, before you start using the tractor again, you need to add a relief to your system to save from more destruction in the future. Either replace the valve with one with a built in relief or install one between your valve and manifold.
 
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You also may want to replace the bolts that secure the bypass block or at least inspect them. They may have stretched which allowed the gasket to blow out. You can check them by just running a nut over the full length of the threads. If there's stretch, the thread pitch will change. If they've stretched, they've been substantially weakened.
 
ricky racer said:
You also may want to replace the bolts that secure the bypass block or at least inspect them. They may have stretched which allowed the gasket to blow out. You can check them by just running a nut over the full length of the threads. If there's stretch, the thread pitch will change. If they've stretched, they've been substantially weakened.
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Gasket I was using was cork. So guessing that is why it blew, I had blown it a couple months prior. But yes I will add a relief. I'm going to hard plum the hydraulics on the Cub like I did the 100. What type of relief valve do you suggest between the valve and manifold?
 
ShawnAgne said:
Gasket I was using was cork. So guessing that is why it blew, I had blown it a couple months prior. But yes I will add a relief. I'm going to hard plum the hydraulics on the Cub like I did the 100. What type of relief valve do you suggest between the valve and manifold?
Click to expand...
Yes, cork gasket material is not the best choice for a gasket on a pressure system. I have no idea what you're running for an auxiliary valve. Can you post a picture?
 
Hi,
The gasket for the side of the Touch Control unit, where the tubes for the pump attach is a sort of hard paper material, as I remember.
Below is a listing for it at TM Tractor Parts, you can look at the picture.
https://www.tmtractor.com/new/hy/310fp.htm

ShawnAgne said:
1. Is the screen plugged possibly from when the gasket blew? It was the top corner towards the front that blew off. Should I pull the TC and clean the screen?
Click to expand...
The filter strainer in the Touch Control is not small, it takes some amount of dirt or other goop to plug it. I think it is about 9" or 10" long. Dale Finch might remember the length of it.
If the strainer is old, they sometimes tear, then there is probably no filtering of the fluid.
You said someone rebuilt the unit, hard to know if he cleaned the strainer or replaced it then.
Below is a listing at TM Tractor Parts for a new strainer. You can look at the pictures.
https://www.tmtractor.com/new/hy/918fp.htm

Below is their listing for the rebuild kit for the Touch Control unit, there are 2 kits, this kit fits the unit that originally came on an early 1950's Cub. The part number is on the left side of the unit to identify which unit it is. The newer unit started being used in later 1954. If someone replaced the unit, it could have any of them on it.
Like was said above, it may not need a rebuild, I put the listing here so you can see what is in the kit. :)
 
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