Case VAC 3-pt hitch does not operate.

Ed in CT

New User
My 1953 ( I think) VAC 3-pt hitch stopped working. The pump sounds like it wants to work. I want to change the fluid but I cannot find what weight to replace it or capacity. My oil is milky.
Any help?? Serial #AC-5656784.
Thanks
 
VAC-5656784 is 1952 model year. The torque tube capacity is 2 gal. Full is to the lip of the fill plug. A general purpose hydraulic oil is suitable, you can buy it at Tractor Supply, some auto supply stores and even some Wal-Marts. Your model should also have a cleanable element type return filter.

Joe
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Thanks a lot Joe, any special ways to bleed system?
Will bad hydraulic oil cause my problem?
Thanks again, Ed
 
The pump is designed to hold some oil in the body so it is basically self priming provided the suction piping is tight and there will be residual oil in the piping. Any air will work out by operating the system

How do you mean it stopped working? Air in the system due to a non-tight suction piping or very low oil level in the torque tube will definitely affect the lift due to aeration of the oil. If the milky oil is due to emulsification, lift will be somewhat erratic but the back pressure will be elevated and will probably blow a large hole in your oil filter causing debris in the sump that can be picked up by the pump and get lodged in the control valve.

Joe
 
(quoted from post at 17:10:31 07/21/16) The pump is designed to hold some oil in the body so it is basically self priming provided the suction piping is tight and there will be residual oil in the piping. Any air will work out by operating the system

How do you mean it stopped working? Air in the system due to a non-tight suction piping or very low oil level in the torque tube will definitely affect the lift due to aeration of the oil. If the milky oil is due to emulsification, lift will be somewhat erratic but the back pressure will be elevated and will probably blow a large hole in your oil filter causing debris in the sump that can be picked up by the pump and get lodged in the control valve.

Joe
The hitch worked fine when I took my saw rig off but now with my carrier on it does not go up or down.
 
The first thing to do is check/clean the return filter and change oil. Let us know if the filter is intact. If it doesn't move at all, either there is no pump pressure or there is a problem in one of the valves.

It is also possible that the O-rings on the piston have completely blown. To check that pull the tubing loose on the vent/leakoff. Let any residual oil in the rockshaft housing drain then operate the hitch, check amount of oil draining. A few small drips is normal, won't prevent the hitch from operating but may drift down with load.

Joe
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(quoted from post at 18:34:08 07/21/16) The first thing to do is check/clean the return filter and change oil. Let us know if the filter is intact. If it doesn't move at all, either there is no pump pressure or there is a problem in one of the valves.

It is also possible that the O-rings on the piston have completely blown. To check that pull the tubing loose on the vent/leakoff. Let any residual oil in the rockshaft housing drain then operate the hitch, check amount of oil draining. A few small drips is normal, won't prevent the hitch from operating but may drift down with load.

Joe
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Joe, I think I found a problem! I pulled the drain plug...a couple drops of water, dug around with a screwdriver and broke the dam! I don't think this has been touched since it was new. Drained most of the fluid then went after the filter, as i removed the last bolt the cover popped off because of the spring and the filter stayed in. The filter seemed enlarged and wouldn't come out of the hole. Needless to say I need a new filter. Do you know where I can purchase/part #?
Also that test you suggested on the vent /bleed off line....the tractor should be running?
Thanks for your help,
Ed
 
Hopefully your problem is that simply solved. While my VAC-14
hydraulic system worked fine I thought I'd change the oil &
filter just for good maintenance. I found the same things you
did: a big slug of dirt blocking off the drain hole and an
expanded filter that came out in pieces.

Best of luck.


Glenn F.
 
(quoted from post at 14:43:49 07/22/16) Hopefully your problem is that simply solved. While my VAC-14
hydraulic system worked fine I thought I'd change the oil &
filter just for good maintenance. I found the same things you
did: a big slug of dirt blocking off the drain hole and an
expanded filter that came out in pieces.

Best of luck.


Glenn F.
Glen,
Thanks foe the vote of confidence. Where did you find parts?
Ed.
 
Plugged drain hole is pretty common. It mostly hard grease that has attracted additional debris precipitating out of the oil. The grease originates from those 4 zerks on the back of the rockshaft and migrates to the sump via the vent/leak-off tubing. That is design process and partly the reason regular oil changes are recommended.

If over greasing those zerks the grease can collect in the rockshaft housing, hardened and block the vent/leak-off tubing. That leads to oil leaking out the control block end of the rockshaft or if that end is very tight an air lock forms under the piston and draft arms fail to drop by gravity, you may even have to stand on them to get the arms down.

The filter element probably swelled up from long term moisture. The element is Case original p/n VT3139 changed to p/n A30411. I checked YT site does not list them. I know John Saeli (315) 585-9826 use to stock them, probably still does.

In any event that is not likely your problem if the hitch doesn't function at all. I am hoping it is the piston seals, a really easy, inexpensive fix. We'll know if that is it when you open the vent/leak-off. Follow procedure here. Pull the tubing fitting, drain the residual oil, if any, from the rockshaft housing (housing fitting can be plugged). Start the engine and work the lever back and forth, attempt to lift the hitch, note quantity of oil draining from the vent/leak-off. A few slow drops is normal, you'll know if the seals are blown.

Joe
 
Forgot to ask, the interior of the filter element is the inlet from the return system should trap the harmful particulates. What was in your element, sludge? metal particles? The element is intact?

Joe
 
(quoted from post at 18:11:41 07/22/16) Forgot to ask, the interior of the filter element is the inlet from the return system should trap the harmful particulates. What was in your element, sludge? metal particles? The element is intact?

Joe

Joe, The element is not intact, I did notice sludge on the inside.
I'll have to order the new filter tomorrow and do your test. While I'm ordering should I get any other pieces like gaskets?
Ed
 
No parts or gaskets yet. If you have to pull the piston you can make that gasket out of 1/32" bulk material from an auto parts store near you. If the piston seals leak we are going to pull the piston to ensure it is factory 1952 and later 2 O-rings as opposed to the prior piston factory to mid 1951 that used a leather cup seal.

The element not being intact is not good news. Fish out all the element material that you can. Put it together, try to determine how much is missing. The bad thing is the pump pickup has no strainer and a chunk of the element can get lodged in the pickup pipe and starve the pump. Little pieces that can get by the pump are large enough to get stuck in the control valve preventing it from closing enough to provide adequate pressure to the piston.

Check the oil you drained for element pieces and anything that shouldn't be in there. I check oil like that by placing an old white tee shirt in a large strainer and strain the oil through it into a pail.

Joe
 
(quoted from post at 19:57:30 07/22/16) No parts or gaskets yet. If you have to pull the piston you can make that gasket out of 1/32" bulk material from an auto parts store near you. If the piston seals leak we are going to pull the piston to ensure it is factory 1952 and later 2 O-rings as opposed to the prior piston factory to mid 1951 that used a leather cup seal.

The element not being intact is not good news. Fish out all the element material that you can. Put it together, try to determine how much is missing. The bad thing is the pump pickup has no strainer and a chunk of the element can get lodged in the pickup pipe and starve the pump. Little pieces that can get by the pump are large enough to get stuck in the control valve preventing it from closing enough to provide adequate pressure to the piston.

Check the oil you drained for element pieces and anything that shouldn't be in there. I check oil like that by placing an old white tee shirt in a large strainer and strain the oil through it into a pail.

Joe



Joe,
I drained the oil, pulled out all the pieces of filter, cleaned sump, checked oil and filter for debri, nothing significant.
I received my new filter today and installed it and filled with hydraulic oil. I did the test with the vent & leak off tube...nothing came out. I ran the tractor a little tried to move hitch up or down and checked the tube again still nothing.
Where do I go from here?
Thanks
Ed
 

I haven't forgotten Ed, have some unscheduled time consuming events pop up that I simply have to address. I am pretty well strung out tonight, just a short post and more tomorrow night if no more surprises.

We are going to have to check out the pump or depth control unit valves next.

The pumps are pretty robust, seldom require repair unless it is run dry. The woodruff keys on the drive gear and pumping drive gear can wear and shear, many hours run time and poor oil condition. Other replaceable parts are bearings and the shaft seal. Pumping gears are mated pairs and when worn along with housing wear should be replaced by another pump rather than repair attempt. Failed shaft seal may suck in air while running and will dump some hydraulic oil into the engine crankcase when stopped. An indication of a failed seal is having to make up oil in the torque tube without any visible external leaks, does this apply to your tractor?

Pic 2 is the pump pressure test procedure. It is only valid if the rest of the system is operational and the hitch can be raised to the upper limit to force the relief valve open. So we need to check out the depth control unit next.

I assume you have the basic factory Eagle hitch hydraulic system like pic 3. No add-on factory remote cylinder control valve or selector valve that someone has piped into the system, correct? Your hitch vent/leak-off tubing Probably enters the torque tube casting under the right step plate rather than going to the breather. Check the circled tube nuts tight and let me know if they were loose.

If you have any weight on the hitch, please take it off if convenient and try to cycle the winch, let me know if any motion. Listen to the hydraulic tubing with a screwdriver to your ear see if you can detect any flow.

That's all for tonight.

Joe
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(quoted from post at 20:15:32 07/26/16)
I haven't forgotten Ed, have some unscheduled time consuming events pop up that I simply have to address. I am pretty well strung out tonight, just a short post and more tomorrow night if no more surprises.

We are going to have to check out the pump or depth control unit valves next.

The pumps are pretty robust, seldom require repair unless it is run dry. The woodruff keys on the drive gear and pumping drive gear can wear and shear, many hours run time and poor oil condition. Other replaceable parts are bearings and the shaft seal. Pumping gears are mated pairs and when worn along with housing wear should be replaced by another pump rather than repair attempt. Failed shaft seal may suck in air while running and will dump some hydraulic oil into the engine crankcase when stopped. An indication of a failed seal is having to make up oil in the torque tube without any visible external leaks, does this apply to your tractor?

Pic 2 is the pump pressure test procedure. It is only valid if the rest of the system is operational and the hitch can be raised to the upper limit to force the relief valve open. So we need to check out the depth control unit next.

I assume you have the basic factory Eagle hitch hydraulic system like pic 3. No add-on factory remote cylinder control valve or selector valve that someone has piped into the system, correct? Your hitch vent/leak-off tubing Probably enters the torque tube casting under the right step plate rather than going to the breather. Check the circled tube nuts tight and let me know if they were loose.

If you have any weight on the hitch, please take it off if convenient and try to cycle the winch, let me know if any motion. Listen to the hydraulic tubing with a screwdriver to your ear see if you can detect any flow.

That's all for tonight.

Joe
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Joe, Do not apologize for taking care of life, we all have that to deal with that. I appreciate all the help you are giving me.
I do have the Eagle Hitch and it is original. The vent and leak off line enters the sump under the left brake pedal on the right side.
I should mention that when I started it after installing filter and changing the oil, I checked the oil level right away and it was somewhat milky which tells me the pump circulated the oil.
When I try to cycle the hitch I can hear the pump bog down when I am in the raise position.
The hitch does not move up or down. No loose nuts. All the weight is off hitch.
Thanks again,
Ed
 
Pump bog and some oil mix, very good observation. Lets see if we can run with that.

Pic 1 is the piston assembly. Lifting and lowering the draft arms by hand will check the entire mechanical end for obstruction, all linkage should move freely all the way up to the piston. The piston will remain in place at the top of the cylinder. The end of the connecting rod nestles in the piston socket, it is not attached. When you lift the draft arms by hand, the connecting rod will slide out of the piston and down the cylinder. Do not drop the draft arms free fall, rod end can strike the piston skirt with enough force to knock a chunk out. There is no way to determine if the piston is stuck in the cylinder at this point but it is very hard to believe that a system capable of ~800 psi is unable to move it unless the oil pressure is not getting there.

Pic 2 is a simple drawing of the system in neutral.

Pic 3 is the draft control unit in the lever neutral position. In neutral the pump oil is circulated directly back to the torque tube via neutral position of the control valve. With the bypass open there is not enough pressure to overcome the lift check valve spring. That red line is the oil flow path.

Pic 4 is the draft control unit in the lever raise position. The control valve has closed off the bypass to the torque tube. The pump pressure is directed to the piston via the lift check valve. Since you can hear the pump bog down indicates an obstruction in the control valve, the lift check valve, or unit passages including the tubing to the piston. There is some possibility that pressure is being bleed off through faulty relief/release valves but that is not consistent with the pump bog. I have never run in to anything like this but I would think it would be in the control valve or the lift check valve. The lift check valve is the most accessible, it is under the plug on the bottom of the draft control unit block. I saw considerable rust when I pulled one on a tractor that had sat for years. Pull the ball and spring and see if you can see anything in the passage. Personally I would roll the engine and try to blow some oil out but consider the mess, might not be worth it.

Joe
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(quoted from post at 14:40:43 07/27/16) Pump bog and some oil mix, very good observation. Lets see if we can run with that.

Pic 1 is the piston assembly. Lifting and lowering the draft arms by hand will check the entire mechanical end for obstruction, all linkage should move freely all the way up to the piston. The piston will remain in place at the top of the cylinder. The end of the connecting rod nestles in the piston socket, it is not attached. When you lift the draft arms by hand, the connecting rod will slide out of the piston and down the cylinder. Do not drop the draft arms free fall, rod end can strike the piston skirt with enough force to knock a chunk out. There is no way to determine if the piston is stuck in the cylinder at this point but it is very hard to believe that a system capable of ~800 psi is unable to move it unless the oil pressure is not getting there.

Pic 2 is a simple drawing of the system in neutral.

Pic 3 is the draft control unit in the lever neutral position. In neutral the pump oil is circulated directly back to the torque tube via neutral position of the control valve. With the bypass open there is not enough pressure to overcome the lift check valve spring. That red line is the oil flow path.

Pic 4 is the draft control unit in the lever raise position. The control valve has closed off the bypass to the torque tube. The pump pressure is directed to the piston via the lift check valve. Since you can hear the pump bog down indicates an obstruction in the control valve, the lift check valve, or unit passages including the tubing to the piston. There is some possibility that pressure is being bleed off through faulty relief/release valves but that is not consistent with the pump bog. I have never run in to anything like this but I would think it would be in the control valve or the lift check valve. The lift check valve is the most accessible, it is under the plug on the bottom of the draft control unit block. I saw considerable rust when I pulled one on a tractor that had sat for years. Pull the ball and spring and see if you can see anything in the passage. Personally I would roll the engine and try to blow some oil out but consider the mess, might not be worth it.

Joe
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Joe,
Tried moving arms by hand, they only raised about 3.5" at the end of the arm. Would not press down at all.
Pulled the plug on the bottom of the draft control unit block, spring and ball came out with a little oil, I bumped engine over (did not start it) and a little more oil. No rust.
Is there a line a can disconnect to drain oil while it lowers the arms?
Ed
 
OK, the problem is mechanical. Draft control unit, hydraulic system is not involved. There should not be any oil on the piton, to check/drain put the lever in the down position engine not running, opening the release valve.

Right now you've moved the draft arms just about the right distance for the connecting rod to pull below the piston and is now hung on the skirt preventing the arms from dropping. Normally you would shake the draft arms up and down to get the rod past the skirt and back seated in the piston socket.

Normally the draft arms can be lifted full up with one hand and back down by gravity with some hand braking to prevent free fall. When you cycle the draft arms like that all the linkage, shaft, conn rod move through their normal up/down cycle. Something is binding, broken, or out of position causing the mechanical seizure. Can you see any external mechanical linkage that has broken or appears to be seized?

Later tonight I will review the mechanical parts exploded view and try to figure out what to disconnect to isolate the problem. Off hand, if the problem is not external, I am thinking conn rod but I just can't see how it could come loose. Another thought is the harden surfaces in the rock shaft housing that is used as bearing surfaces for the rock shaft. If you haven't already done so, grease those 4 zerks on the back of the rock shaft housing.

Anyone else here have any ideas, jump in, the more views the better.

Joe
 
In viewing the parts manual it appears that the most likely seizure points would occur from an adrift conn rod or seized bearing surfaces on the rockshaft/housing.

If the conn rod is not adrift the top round end is probably now resting on the canted cylinder wall caught up under the piston skirt. If you could jog the draft arms it would bounce free and continue travel up into the piston socket. The operation force on the lower end of the rod, both hitch up & down, is to seat the rod in the socket. There is no operation force on the pins. That is not to say the rod could not come adrift and lodge someway to prevent the rockshaft from rotating. Murphy's law applies.

The arrows point to the 4 bearing surfaces on the rockshaft that line up with the bearing surfaces in the rockshaft housing and the grease zerks on the back. These surfaces are possible seizure points especially if the hitch is dormant for an extended period. One thing to consider, if the hydraulic is in good shape @ ~ 800 psi on the piston there is a considerable force being applied to rotate the rockshaft if the force is in fact available for rotating it.

I would pull the pins at the end of the lift arms (circled) and separate the hitch to narrow down the seized area.

Joe
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(quoted from post at 18:14:34 07/27/16) OK, the problem is mechanical. Draft control unit, hydraulic system is not involved. There should not be any oil on the piton, to check/drain put the lever in the down position engine not running, opening the release valve.

Right now you've moved the draft arms just about the right distance for the connecting rod to pull below the piston and is now hung on the skirt preventing the arms from dropping. Normally you would shake the draft arms up and down to get the rod past the skirt and back seated in the piston socket.

Normally the draft arms can be lifted full up with one hand and back down by gravity with some hand braking to prevent free fall. When you cycle the draft arms like that all the linkage, shaft, conn rod move through their normal up/down cycle. Something is binding, broken, or out of position causing the mechanical seizure. Can you see any external mechanical linkage that has broken or appears to be seized?

Later tonight I will review the mechanical parts exploded view and try to figure out what to disconnect to isolate the problem. Off hand, if the problem is not external, I am thinking conn rod but I just can't see how it could come loose. Another thought is the harden surfaces in the rock shaft housing that is used as bearing surfaces for the rock shaft. If you haven't already done so, grease those 4 zerks on the back of the rock shaft housing.

Anyone else here have any ideas, jump in, the more views the better.

Joe


Joe, I removed the cylinder, when it came off the arms dropped all the way down. So i'm guessing the piston is stuck. I'm looking for the best way to try and remove it. It does not appear to be crooked in the cylinder. See photo. There is about 3/8-1/2" of the piston exposed. Should I try to grab that with a strap wrench? Suggestions???

Ed
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Use a block of wood and a BFH tap the piston back up into the cylinder. Clean up the cylinder wall and lube. Also try to get some lube up between the piston and the cylinder wall. The lube may help prevent/reduce scoring of the cylinder.

A puff of compressed air to hydraulic fitting is usually the method of blowing the piston out of the cylinder. Be very careful, the piston can exit with a lot of velocity and force. To be safe it is a good idea to turn the hydraulic fitting ccw 180 degs so it points to the top of cylinder and tie a cloth bag around the cylinder flange to catch the piston as it exits the cylinder.

Your last post stated the draft arms were seized in the down position. Piston stuck in bottom of cylinder indicates they got stuck with the arms in the up position at some point. What happened there?

Joe
 
Hook a hydraulic hose to the input side and it will be safer to push out the piston out. I worked for a hydraulic cylinder company and air can make a projectile out of a rod or piston that will make a funny story if no one gets hurt you and find all the parts.
 
(quoted from post at 09:04:36 07/31/16) Use a block of wood and a BFH tap the piston back up into the cylinder. Clean up the cylinder wall and lube. Also try to get some lube up between the piston and the cylinder wall. The lube may help prevent/reduce scoring of the cylinder.

A puff of compressed air to hydraulic fitting is usually the method of blowing the piston out of the cylinder. Be very careful, the piston can exit with a lot of velocity and force. To be safe it is a good idea to turn the hydraulic fitting ccw 180 degs so it points to the top of cylinder and tie a cloth bag around the cylinder flange to catch the piston as it exits the cylinder.

Your last post stated the draft arms were seized in the down position. Piston stuck in bottom of cylinder indicates they got stuck with the arms in the up position at some point. What happened there?

Joe

The arms were stuck in the up position, I could only move them 3.5" when lifted by hand. I have put PB Blaster on the outside of piston and I was able to drain the rest of the oil from the cylinder (it looked like chocolate milk). I was able to squirt some WD-40 into the cylinder via the 90 degree fitting. I am letting that soak good and will probably redo a couple times as I tried once to drive it in with no luck.

Ed
 

Thanks for the info Barry I plan to be real careful Not sure I have the hydraulic capabilities but I can pump air by hand.
 
(quoted from post at 16:00:54 08/01/16)
Thanks for the info Barry I plan to be real careful Not sure I have the hydraulic capabilities but I can pump air by hand.

Barry is right, much better control with hydraulic than compressed air especially with a stuck or hard to move piston. Normally all you would need to move the piston out is a puff of air at the fitting.

Since the piston is stuck that hard there must be considerable rust involved. The thing we want to avoid is scoring the cylinder wall. Soak with penetrate and tap until you can just move the piston but don't drive it up the cylinder. Then try your hand pump. Doubtful a hand pump will build up enough pressure if the air leaks by the piston but give it a shot.

Alternately compressed air held by hand to the fitting (not threaded) and a cloth/burlap bag tied around the flange to catch the piston isn't all that risky.

Joe
 

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