Testing a hydraulic pump

[Xfaxman]

On the TORO+Loader, I put a gauge on the control valve. It is in the the pressure in port from the pump.

Shows the pressure in lift or curl when in use.

Visible from the seat.

 

[Alesandro]

Ok guys did some testing with a pressure gauge and the following is what I got;

I put the pressure gauge right before the inlet of the control valve assembly, started up the tractor and let it warm up for about 5 mins. I get "0" when I don't pull any levers, when I pull the bucket up lever I get around 1800psi and the same for bucket tilt. I then started to move some dirt around and maybe 10mins into the ordeal my bucket up starts to slow down. The pressure needs to rise slowly before I can get the bucket to come up. After a while the bucket will not come up very fast and needs to build pressure before it moves. After a while the empty bucket will not rise and the gauge won't go any higher than 850-900psi. The whole time during testing the bucket tilt didn't seem to have a problem and when I reached the extends of the bucket tilt the pressure shot really fast to about 1800psi and squealed.

Please keep in mind I did change the control valves a couple days ago and I still had the issue.

Does this tell me that there is something wrong with the pump, the lines for the bucket lift after the control valve, or maybe my pressure relief valve.

 

[Alesandro]

What do you think of this hypothesis;

I still think it may be the pump. Even though it can still reach the 1800psi mark with my bucket tilt, that uses (1) hydraulic cylinder, it needs to build up pressure on the bucket lift as there are (2) hydraulic cylinders, but, my flow rate has decreased. So the pump can still hit 1800psi but at a much slower rate than when cold.

Just so everyone is aware, apparently the hydraulic shops around here are super busy and it would take about 2 weeks to get the pump tested, as that would be the best way to test for flow rate.

Just a guess let me know what you think.

 

[wdchyd]

...................... After a while the empty bucket will not rise and the gauge won't go any higher than 850-900psi. The whole time during testing the bucket tilt didn't seem to have a problem and when I reached the extends of the bucket tilt the pressure shot really fast to about 1800psi and squealed.

Please keep in mind I did change the control valves a couple days ago and I still had the issue.

Does this tell me that there is something wrong with the pump, the lines for the bucket lift after the control valve, or maybe my pressure relief valve.

You may only have a blown piston seal in one of the lift cyls

 

[jabelding]

That's a second on the piston seal. It can be checked by warming everything up where the loader wont work, removing the cylinders from the loader but keep the hyd lines attached extend the cylinders all the way out then remove the hose from the rod end and try to extend the cylinders more if you have oil coming out of the cylinder port at the rod end the seal is bad in that cylinder. If it is easier you can also do it the other direction as well. Just be careful which way you are moving the lever or you will have a big mess.

 

[jenkinsph]

Was the squealing the relief valve by passing?

The lower pressures of 850 to 900 psi while the loader was moving slow can indicate the fluid is by passing the cylinder piston seals.

 

[Alesandro]

Was the squealing the relief valve by passing?

Yes I believe the squealing was at the relief valve on the valves controller. So, is squealing a bad thing or is it just what it is?

 

[Alesandro]

I will take apart the bucket cylinders today and hopefully have them rebuilt later today or tomorrow. I'll post with the results when done.

Thanks for all the help guys!

 

[jenkinsph]

Yes I believe the squealing was at the relief valve on the valves controller. So, is squealing a bad thing or is it just what it is?

It would indicate to me the pump is good. Particularly since you said the pressure shot up fast at the end of stroke.

Did you try out the three point hitch with a heavy load on it?

 

[Alesandro]

Did you try out the three point hitch with a heavy load on it?

The three point hitch always seems to work. The heaviest I have had on it is the rototiller and it has always lifted it fine. I don't know how heavy it is compared to the FEL assembly though, but it seems pretty heavy. I agree the pump is good. I'm still really new to this tractor and hydraulic stuff and I am learning so great stuff along the way.