Hydraulic pump whine after valve installation?

[winston1]

Woops, I misunderstood, I'll blame it on old age. This is a mighty unusual problem. Something has got to be tied into your new valve if you didn't have this noise before installation.

 

[Gypsyman]

Here is my thinking....add a few quarts too much oil and try that. Just throwing that out you can always drain some with a siphon later.

My other thought is why have the clutch in anyway? It will be out when working any way or most of the time guess I dont see why it would matter either way just seems strange to me to have the clutch in I guess.

I agree. I just happened to have it latched down during testing in the shop so that I could stand by the tractor and start it from the right hand side where the control valve is. Never thought to let it back out as it shouldn't have made any difference.

 

[Gypsyman]

As I'm sitting here thinking about this I may have been causing the problem myself. Since the strainer cavity drains back to the tank on shut down and the system must run for a minute to clear itelf of air that may be the problem.

Since the tractor was warmed up I would fire it up and go straight to moving the control valve for testing. If the system starts with air in the strainer cavity everytime and I wasn't giving it time to purge before moving the valve I guess I could have been sending air into the control valve system myself. Maybe the nut behind the wheel is the root cause of the issue. LOL!

 

[J_J]

Some excerpts I found,

Relief Valve Check
Hydraulic pumps typically include a relief valve, or valve that opens and closes to control the pressure in a hydraulic system. Oil buildup or other sediment in the relief valve can hamper its ability to close properly, thereby enabling higher pressure to pass through the system, resulting in a whistling noise. Cleaning the relief valve with a damp cloth typically corrects the problem.

Intake Restriction
Foil, flashing or other objects lodged in the hydraulic pump's inlet, or opening that allows hydraulic fluid into the pump, can restrict the pump's intake and result in a whining noise. Cleaning out or removing any obstructions at the pump's inlet should eliminate the whining.

Oil Moisture
Leaks in one or multiple hydraulic lines can allow air or moisture to mix with hydraulic oil. This added air can result in a high-pitched whine while the hydraulic pump is in operation. Replacing the damaged lines should resolve the whining issue and restore optimum function to the pump.

 

[oldnslo]

As I'm sitting here thinking about this I may have been causing the problem myself. Since the strainer cavity drains back to the tank on shut down and the system must run for a minute to clear itelf of air that may be the problem.

Does the tranny pump help fill the sump area for the hydraulic pump? From what you are describing it sounds like there has to be some external fluid flow filling that cavity since if the pump inlet is above oil level it would never prime.

I was always told it was the nut holding onto the wheel that caused the problems

 

[J_J]

You might recheck all your hyd fittings to see if they are restrictor fittings. If the fitting is a 1/2 in fitting, you should see a 1/2 hole.

I purchased a 3/8 fitting one time and when I looked through it, the hole looked about 1/8 in. It was a restrictor fitting, and someone put it in the wrong bin, and the counter man did not check it.

 

[California]

FWIW - On this model it is a known characteristic that there is a delay - maybe 30 seconds - between starting the engine and when the 3 point will respond to the lift lever. (there's still a delay, but less, on a re-start).

Whatever causes that might be relevant to your analysis.

And confirming what you noted - the lift lever is 'all or nothing', near impossible to feather. This also is a known characteristic for this model.

In contrast my YM240 lift moves immediately and is easy to feather, confirming that those are real model-specific characteristics.

 

[aczlan]

What happens if you run it enough to get all the air worked out, then push in the clutch and try your tests again?

Aaron Z

 

[Gypsyman]

FWIW - On this model it is a known characteristic that there is a delay - maybe 30 seconds - between starting the engine and when the 3 point will respond to the lift lever. (there's still a delay, but less, on a re-start).

Whatever causes that might be relevant to your analysis.

Sorry for the delay guys. I'm slammed at work with Christams orders.

This known issue is exactly what was causing the problem. I confirmed that the delay is caused by the strainer area draining back to the sump. Upon startup the system pulls all of the air thru and sends it back to the sump before the strainer chamber refills.

Just to prove my theory I cut a piece of plexi to cover the strainer location so that I could watch the fluid level. Sure enough, it takes 15-30 seconds for the system to purge the air and start pumping fluid. It clear much faster if the clutch is released because you have both the powershift pump and the hydraulic pump pulling prime instead of just the hydraulic pump.

By operating the control lever too soon after startup I was sending this air pocket into the control valve over and over again.

By waiting roughly 30 seconds after startup the system is now smooth and quiet, as it should be. I never experienced this problem with the 336D because the strainer is located below the fluid level and the system never loses prime.

Glad I understand what was happening now but what a pain in the butt to track down.

Thanks to all who responded. Your time in tracking this down is truly appreciated. :thumbsup:

Here's the little brute with the blower mounted...

 

[aczlan]

Thats quite the cylinder to rotate the chute...


Aaron Z