Is my pump going/shot?

logman81 · February 05, 2016, 08:52:54 AM

When I get back over to the machine after the snow storm I'll take some pics and turn the relief screw in till I hear the motor change and see if that helps. I don't believe it's a bad cylinder that caused it. The whole system is very sluggish and this has happened over time getting progressively worse. I did run it extremely low on oil to the point where it was doing the same thing. I put oil in and it started working again for a while about two months, now I have no pressure unless I throttle it way up. I'm wondering if I killed the pump?

Corley5 · February 05, 2016, 09:59:16 AM

Gear pumps are more forgiving than vane or piston pumps but none of them handle cavitation well. Your pump is more than likely done for. I was going to post a link to Surplus Center's pump sizing calculator but can't open their site this morning. Google won't work here either :-\

sandsawmill14 · February 05, 2016, 11:17:31 AM

Quote from: logman81 on February 05, 2016, 08:52:54 AM
When I get back over to the machine after the snow storm I'll take some pics and turn the relief screw in till I hear the motor change and see if that helps. I don't believe it's a bad cylinder that caused it. The whole system is very sluggish and this has happened over time getting progressively worse. I did run it extremely low on oil to the point where it was doing the same thing. I put oil in and it started working again for a while about two months, now I have no pressure unless I throttle it way up. I'm wondering if I killed the pump?

most likely

logman81 · February 05, 2016, 01:51:19 PM

That's not what I want to hear but it looks pretty easy to replace.

Corley5 · February 05, 2016, 05:42:17 PM

http://www.surpluscenter.com/Tech-Help/Hydraulics/Calculators/Gear-Pump-Replacement/

logman81 · February 05, 2016, 08:13:56 PM

Thanks once I get the pump off I'll see if I can get it apart and measure it.

OntarioAl · February 06, 2016, 01:01:41 PM

Just a thought before you install the new pump check the suction side right back to the tank. Things to look for are blockage or a partial collapse of the intake hose, look for an in tank screen that might be partially blocked.
I find it hard to believe that some one would design a hydraulic system an not have some form of protection keeping crud out of the system.
Al

logman81 · February 06, 2016, 05:46:24 PM

Yeah I'm going to take the top cover of the transmission off and see if it's in there.

logman81 · February 07, 2016, 02:04:49 PM

Ok guys I'm back at the skidder. I started it up and at a idle I have pressure to the hydraulics when the oil is cold with decant speed out of the pistons. Is it the pump?

logman81 · February 07, 2016, 04:19:01 PM

There is no screen or strainer in either the suction or return line. I even pulled the cover off the transmission and stuck my hand in there and couldn't find anything.

s grinder · February 07, 2016, 05:25:43 PM

I know you checked the suction line,the suction side of pump the might have a screen in it.If you take the line off,maybe the line is collasped.One last thing,i would hook up a line from suction side of pump to a 5 gallon can and see how your hyd. and steering works.That would eliminate all prospects.

OntarioAl · February 07, 2016, 05:26:59 PM

logman81
Hydraulic oil at operating temp and a pressure gauge will pin down whether it is the pump or not.
I still find it hard to believe that your machine does not have some sort of filtration to protect the hydraulic system and the transmission. Is there nay indication that in the past somebody re-plumbed the system and turfed the filter(s)?
Al

logman81 · February 07, 2016, 06:02:35 PM

It has a steel line with a short piece of rubber hose connecting it to the pump. To the best of my knowledge it is the original pump cause it still has some of the original color paint on it.

logman81 · February 07, 2016, 06:10:43 PM

Here is the pics of pump and valve bank.

logman81 · February 07, 2016, 06:56:45 PM

I think before I take the pump off I'm going to make a pressure gauge to get a read on what pressure I'm getting to the cylinder.

logman81 · February 07, 2016, 08:06:09 PM

What's the proper procedure to test the pressure?

Corley5 · February 07, 2016, 08:20:11 PM

Did you check the pump driveline? There isn't a compromised key or spline that's slipping? That's a longshot but it could be. I had issues with misalignment with my Mule that I finally solved by putting in a Lov-Joy Coupler. It would wear out splines and start slipping. Don't lose too much time diagnosing when a couple hundred dollar pump will solve your problem ;)

logman81 · February 07, 2016, 08:28:05 PM

No slipping that I can see or hear. I started it first thing this morning and had pressure probably do to the oil being thick. Once warm is when the problem is occurring.

MikeZ · February 07, 2016, 08:30:05 PM

Are you sure the short section of hose isn't being sucked shut as operating temp increases. Old hoses tend to degrade with time. Just a thought.

logman81 · February 07, 2016, 08:50:22 PM

Yup very sure of that it is only about four inches long and is actual suction hose.

s grinder · February 08, 2016, 08:48:39 AM

Does it have a trans filter/filters?

logman81 · February 08, 2016, 01:50:30 PM

Nope standard trans. Once this storm blows over I'm going to get the parts to rig up a pressure gauge to check the pressure, that should tell me everything I need to know.

s grinder · February 08, 2016, 06:12:55 PM

On one of your pictures,looks like you have a tag on that pump.Maybe the manufacture, serial number?

chevytaHOE5674 · February 08, 2016, 06:34:06 PM

Quote from: logman81 on February 07, 2016, 08:50:22 PM
Yup very sure of that it is only about four inches long and is actual suction hose.

Just because it is short and actual suction hose doesn't mean that it isn't collapsing internally.

On a tractor of mine I had an actual wire reinforced suction hose that looked perfect on the outside collapsed on the inside and caused some of the same symptoms.