I got the used pump today and it's a little dirty on the outside (expected), no biggie. Can I completely open the pump and inspect it, or will I need to buy new seals once I crack it? I would like to look inside of it before installing it.
Testing a hydraulic pump
- Thread starter bobcube
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mrmikey
Elite Member
Best bet is to put it on the main pressure line into the valve, that way you can test each section without having to move the gauge around. Not sure of the pressure, I'd say 12-1500+, if someone tells you different, believe them because I'm not sure of your system.............Mike
mrmikey
Elite Member
And you would be looking for....... Unless the defects are blatantly obvious you're not going to see anything.............Mike
wdchyd
Elite Member
x2........and if the defects are blatantly obvious the pump is junk anyways
DLTTrekkers
Veteran Member
Checking the pump by inserting a gauge at the external brakeaways ...start the engine and let it idle ...note the pressure....take the revs up and note the pressure and now by holding that pressure there decrese the revs and note the pressure....if pressure drops with revs dropping ...to me it means a backflow of oil throu the pump....that pump needs replacing
dfkrug
Super Member
- Joined
- Feb 3, 2004
- Messages
- 7,695
- Location
- Santa Cruz Mtns, CA
- Tractor
- 05 Kioti CK30HST w/ Prairie Dog backhoe, XN08 mini-X
I would open it up to see if it is clean inside. Used pumps may not have been protected from
dirt getting into the open ports. You can see if it is damaged inside by dirty fluid: look for
scoring. Furthermore, cavitation damage and bad seals may be visible (photo).
I tend not to trust used hyd pumps, motors, valves.
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dfkrug;
What caused the marks in your provided pic? I want to open it but the only thing I need to know is will I need to new seals that I might not be able to replace, then I would still need another pump.
After talking to a couple facilities here about getting my pump tested they will all open the pump and visually inspect the condition of the pump and to verify there is nothing in the pump that could damage their equipment.
I personally would like to open it and take measurements, see how it works, and stuff like that. I was the kid that took about the drill to see how it worked.
Thank you for suggesting this method and I will try it. One question I have is would it hinder or be bad to get a gauge, tee a line off one of my cylinders to my gauge and mount it so I could always visually inspect the pressure, or, once the system is in full working order would it even be needed?
Thanks for the help guys.
dfkrug
Super Member
- Joined
- Feb 3, 2004
- Messages
- 7,695
- Location
- Santa Cruz Mtns, CA
- Tractor
- 05 Kioti CK30HST w/ Prairie Dog backhoe, XN08 mini-X
My theory on the failure was the user was operating tractor on relief for an extended period
and overheated the fluid.
The simplest pressure test uses a gauge at the end of one working port hose, often on the
loader. No Tee plumbing required.
dfkrug;
My thoughts for the tee was to keep it on either permanently or until I get this issue figured out. When I 1st start up the bucket works fine, (I pressume I have all the hydraulic pressure I am supposed to have), after a while it slowly loses hydraulic pressure. One thing I forgot to mention that when it gets to it's weakest point, the bucket will actually start to lower in between my shift from pushing my lever all the way up back down to middle. I hope I explained that correctly. Meaning if I have a load that say is 3' high and that's the farthest it can go, then when I put my lever back to center, there is a short time that the load will actually start to lower, before I hit center.
I was thinking about having the gauge mounted and I could monitor my pressure, then as everything starts to warm up I assume I could watch it drop. I read another place where my MT 372 D hydraulic pressure should be 1950psi. If I am not even getting that from the get go would that not help pin point the issue as well.
Thanks for all the help.
My thoughts for the tee was to keep it on either permanently or until I get this issue figured out. When I 1st start up the bucket works fine, (I pressume I have all the hydraulic pressure I am supposed to have), after a while it slowly loses hydraulic pressure. One thing I forgot to mention that when it gets to it's weakest point, the bucket will actually start to lower in between my shift from pushing my lever all the way up back down to middle. I hope I explained that correctly. Meaning if I have a load that say is 3' high and that's the farthest it can go, then when I put my lever back to center, there is a short time that the load will actually start to lower, before I hit center.
I was thinking about having the gauge mounted and I could monitor my pressure, then as everything starts to warm up I assume I could watch it drop. I read another place where my MT 372 D hydraulic pressure should be 1950psi. If I am not even getting that from the get go would that not help pin point the issue as well.
Thanks for all the help.
Xfaxman
Super Star Member
- Joined
- Feb 8, 2013
- Messages
- 13,293
- Location
- Guthrie, OK
- Tractor
- Toolcat 5610 G - Bobcat V417 - TORO+Loader
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.
Shows the pressure in lift or curl when in use.
Visible from the seat.
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.
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.
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.
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
Elite Member
You may only have a blown piston seal in one of the lift cyls
jabelding
Gold Member
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
Super Star Member
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.
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.
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?
jenkinsph
Super Star Member
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?
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.
