Hydraulic question

bbuckler

bbuckler

Tractorologist
Senior Member
Member
Can a hydraulic pump going bad cause engine to lose power ? It would barely go in 2nd and 3rd but if I move the lever it would rev back up and have plenty of power. I think I burnt the pump up loading it on the trailer after clutch job without fluid in the touch control because when I got fluid in it and ran it the pump got out the o rings melted and now it leaks.



https://www.facebook.com/groups/485306901540776/?epa=SEARCH_BOX#
 
What kind of tractor is this? Assuming it’s a farm tractor, I think a lot of machines used a common reservoir, in which case I could see that being your issue. There should be more knowledgeable members along soon!
 
Ryan313 said:
What kind of tractor is this? Assuming it’s a farm tractor, I think a lot of machines used a common reservoir, in which case I could see that being your issue. There should be more knowledgeable members along soon!
Click to expand...
Farmall Cub
 
bbuckler said:
anybody tried one ? FARMALL CUB HYDRAULIC PUMP 352035R94 | eBay
Click to expand...
They really don't say much about it...... New pump? Rebuild? Tear off that's been cleaned?

I kind of doubt the pump is your problem but it sounds like it needs to come off anyhow. Pull it off and see. If you run the engine with it off I think it's going to throw a lot of oil around. If you don't have a block off plate you can buy one, make one or just pull the gear off the pump and put it back to close the hole.
 
Compression is good , oil pressure is good. Only when the touch control is in the center that the tractor has plenty of power
 
I'm starting to think something didn't go back together right when we split the tractor it will start but it hard to hand crank now.
 
Relief valve somewhere blocked?

Return hose to tank restricted?

If not a mechanical problem with the pump then something in the system is causing the pump to work harder and pulling the engine down with it.

I didn't look super hard, but I couldn't find a hydraulic schematic.

Or you have an entirely different problem.
 
Sounds like the hydraulic control might be sticking and not returning to neutral, which could load up the pressure, and if so, would overheat the pump fast!
 
bbuckler said:
Only when the touch control is in the center that the tractor has plenty of power
Click to expand...

That is the clue there.

The touch control isn't like many of the hydraulic systems we're familiar with. When you move the lever you really aren't doing a raise/lower operation but setting a target position for the hydraulic cylinder. When the cylinder is out of position relative to the lever it actuates the valve causing it to move. Once it reaches the target position it returns the valve to the neutral position.

The system has a fairly conventional pressure relief valve that limits the system pressure to about 1,100psi. It also has a pressure control valve that should drop system pressure to about 50psi. when the hydraulic valve is in the neutral position. If that's not working it's going to put quite a load on the engine.

Since the valve should return to the neutral position and unload the hydraulic pressure regardless of where the control lever is positioned it sounds like you've got a problem with the touch control unit itself.

There isn't any slop in the hydraulic system. My Cub was at a show this weekend where children moved the touch control lever. My starter is dead so I have to hand crank it. It cranks hard until the hydraulics reach the neutral position.
 
Last edited:
I will rebuild the system see if that fixes it. If the drive shaft splines isn't lined up correctly what would the symptoms be ?
 
bbuckler said:
I will rebuild the system see if that fixes it. If the drive shaft splines isn't lined up correctly what would the symptoms be ?
Click to expand...

The Cub doesn't have what I'd call a drive shaft. Are you talking about the transmission input shaft engaging the clutch plate splines? The tractor won't go back together if they aren't lined up.
 
MiCarl said:
The Cub doesn't have what I'd call a drive shaft. Are you talking about the transmission input shaft engaging the clutch plate splines? The tractor won't go back together if they aren't lined up.
Click to expand...
Yep and good to know I was afraid it was something to do with that and had to split the tractor again. It shifts fine still sometimes grinds going into first or reverse
 
I think that grind from neutral is probably normal. It's sitting there spinning in neutral and then you put the clutch in. It doesn't take much drag in the pilot bearing to keep it going. I throttle way down and move the shifter quickly to minimize grinding.
 
bbuckler said:
Can a hydraulic pump going bad cause engine to lose power ? It would barely go in 2nd and 3rd but if I move the lever it would rev back up and have plenty of power. I think I burnt the pump up loading it on the trailer after clutch job without fluid in the touch control because when I got fluid in it and ran it the pump got out the o rings melted and now it leaks.
Click to expand...
I found this info from a manual my son got online... I can ask him to find more if u need.. but for now try this
Step 1
Relieve the hydraulic-system pressure before attempting to repair any leaks. Ensure the tractor engine is not running, since the engine usually operates the hydraulic pump.
Step 2
Securely tighten leaking hoses or tubing nuts.
Replace the hydraulic tubing or the cut or damaged hoses.
Leaking Components
Step 1
Reseal leaking fittings on hydraulic components. Unscrew the fitting from the component with a wrench. Remove and replace O-rings or other seals on the fitting. Then screw the fitting back onto the component.
Step 2
Replace the components you may be unable to reseal, such as the tractor's hydraulic pump.
Remove and reseal leaking lift cylinders or other hydraulic cylinders. You can usually purchase a seal kit for each cylinder -- containing every seal needed to rebuild the cylinder.
Tip
  • If you find leaky hydraulic cylinders and you don't feel comfortable resealing them, replace them.
Warning
  • Don't search for hydraulic leaks by feeling around with your hand. Pressurized fluid squirting through a pinhole can puncture the skin.
 
David88 said:
I found this info from a manual my son got online... I can ask him to find more if u need.. but for now try this
Step 1
Relieve the hydraulic-system pressure before attempting to repair any leaks. Ensure the tractor engine is not running, since the engine usually operates the hydraulic pump.
Step 2
Securely tighten leaking hoses or tubing nuts.
Replace the hydraulic tubing or the cut or damaged hoses.
Leaking Components
Step 1
Reseal leaking fittings on hydraulic components. Unscrew the fitting from the component with a wrench. Remove and replace O-rings or other seals on the fitting. Then screw the fitting back onto the component.
Step 2
Replace the components you may be unable to reseal, such as the tractor's hydraulic pump.
Remove and reseal leaking lift cylinders or other hydraulic cylinders. You can usually purchase a seal kit for each cylinder -- containing every seal needed to rebuild the cylinder.
Tip
  • If you find leaky hydraulic cylinders and you don't feel comfortable resealing them, replace them.
Warning
  • Don't search for hydraulic leaks by feeling around with your hand. Pressurized fluid squirting through a pinhole can puncture the skin.
Click to expand...
The machine does have a few small leaks that need to be fixed anyway, maybe fixing them will solve my isssue. Honestly I do not fully expect it to, as reverse is strong but I will try it when I get the chance.
 
You must log in or register to reply here.
Back
Top