Hydraulic Pump Cafitating

[Dave5264]

Hi fiolks, my 2008 5264 Montana (ie a Romanian UTB/Universal) has ongoing noises from the hyd pump (like someone shaking a tin can with nuts in it). Happens more when the tractor is under hydraulic load, and worse again when the tractor has been operating for a while & is hot.

Dealer replaced the pump under warranty a year ago but the noise still persisted.

Dealer did a avariety of other checks including trying a more free flowing Filter (With Montana's blessing). which helped a bit

the loader is also "jerky" in upward load motion once it all gets hot, ie not smoth

Trans Hydraulic fluid levels are good, oil looks clean etc.

Ill be getting a filter change shortly to see if that helps.

it wasnt too bad this summer, but now that Im into a project that requires using the loader alot, Its more noticeable again.

any ideas. ?

 

[5030]

It's caveatting. You either have air entrained in the fluid (something on the suction side is loose allowing air to enter the fluid flow or the flow isn't sufficient for the pump capacity.

Per chance did you fool with the pressure settings on your loader??

 

[Dave5264]

No, havent done anything re pressure settings on the loader. To be honest I have no idea what that is or how to do it.

It does seem to improve after a filter change (recalling last year).

the dealer checked all the lines for blockages and did some sort of pressure/volume test (dont recall exactly what they called it).

They did say that UTB painted/primed the inside of the casings on these tractors 9for some unknown reason), and that had caused issues with filters clogging up.

In my case the filter change helps, but doesnt resolve it completely

is there an easy way to detect where air may be entering the system ?
is there a way to validate the correct pressure settings on the loader ?

are both of these activities best done via the dealer ?

thanks !

 

[J_J]

This is what causes cavitation.

Cavitation occurs when the volume of fluid demanded by any part of a hydraulic circuit exceeds the volume of fluid being supplied.

This causes the absolute pressure in that part of the circuit to fall below the vapor pressure of the hydraulic fluid. This results in the formation of vapor bubbles within the fluid, which implode when compressed.

It is not caused by air being sucked in, but that in itself is a problem with adding air to the hyd fluid.

On my hydrostatic transmission, when I press hard on the pedal, the cavitation starts because I am asking the pump to put out more fluid than it is taken in.

VSP pumps usually have a filter in the suction side of the pump, because the hydrostatic transmission like very clean fluid.

AS far as checking pressure , install a 3000 psi hyd gage in the IN port of the FEL valve. Or make up a portable plug in test rig like this.

You will have to know your tractor pump pressure in order to to see if it is correct.

 

[5030]

This is what causes cavitation.

Cavitation occurs when the volume of fluid demanded by any part of a hydraulic circuit exceeds the volume of fluid being supplied.

This causes the absolute pressure in that part of the circuit to fall below the vapor pressure of the hydraulic fluid. This results in the formation of vapor bubbles within the fluid, which implode when compressed.

It is not caused by air being sucked in, but that in itself is a problem with adding air to the hyd fluid.

On my hydrostatic transmission, when I press hard on the pedal, the cavitation starts because I am asking the pump to put out more fluid than it is taken in.

VSP pumps usually have a filter in the suction side of the pump, because the hydrostatic transmission like very clean fluid.

AS far as checking pressure , install a 3000 psi hyd gage in the IN port of the FEL valve. Or make up a portable plug in test rig like this.

You will have to know your tractor pump pressure in order to to see if it is correct.

Dang, I learned something....... sort of.

If there is any leak on the suction side, it will allow ambient air to permeate the fluid causein pump niose.

 

[J_J]

Here is a picture of what cavitation can do.

http://upload.wikimedia.org/wikipedia/commons/thumb/b/bf/Cavitation.jpg/266px-Cavitation.jpg

 

[Egon]

Is the hydraulic fluid being used the proper one?

When using the hydraulics at a very slow rate does anything change?

Is there another filter or screen somwhere in the hydraulic circuit?

 

[Dave5264]

Is the hydraulic fluid being used the proper one?

When using the hydraulics at a very slow rate does anything change?

Is there another filter or screen somwhere in the hydraulic circuit?

Hi, Yes the corect Fluid is in use, I get the noises at low and Hi RPM.

I suspect the main filter is clogging again, I need to find out if there is another pickup screen somewhere on my pump, if so I need to check that.

thanks for the Input guys, I appreciate it.

 

[J_J]

Dave5264,

If you don't have a manual, then drop by the dealership and look at the service manual and parts manual. He will probably print out a page or two for you .

 

[Dave5264]

Dave5264,

If you don't have a manual, then drop by the dealership and look at the service manual and parts manual. He will probably print out a page or two for you .

will do, thanks