I have a 25hp Agtrac tractor. Bought on Marketplace, first mistake... Replace all hoses/lines from Control to FEL... Rebuilt all FEL cylinders. FEL works but is weak. Only lift about 300 lbs. Bought gauge and checked pressure. At fast idle - 800 to 900 psi. At 2000 rpm 1100 psi. The Pump has been replaced by previous owner. Looking for advice - What is the valve at the pump? (see picture)The high pressure line goes to the FEL control valve - Can see the small line at the bottom of the valve going back to the pump. The bottom of the valve where the small line is attached is adjustable - it screws in and out and is sealed by an o-ring. The small line hooks up to it. The Control valve also has what appears to be a pressure relief valve. (see picture)The set screw in it appears to be as tight as it can be. Questions: Are both these valves pressure relief? Is there a way to increase pressure to have reasonable lift capacity? How do I isolate the pump to see if it is the problem? Any help is greatly appreciated...
Hydraulics Questions
- Thread starter flholman
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TractorTech
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Hard to tell anything from your pictures as they are very close up.
You can test the pump by putting a gauge on the outlet of the pump only. This essentially deadheading the pump. DO NOT START THE TRACTOR. Crank over the engine to get a pressure reading. Guessing you should see about 2500 psi.
Hard to tell anything from your pictures as they are very close up.
You can test the pump by putting a gauge on the outlet of the pump only. This essentially deadheading the pump. DO NOT START THE TRACTOR. Crank over the engine to get a pressure reading. Guessing you should see about 2500 psi.
oldnslo
Super Member
First question is do you know what pressure the system is supposed to operate at?
When starting from ambient temperature does that pump housing get hot quickly vs pump inlet line when trying to build pressure? If yes the pump is potentially slipping or bypassing oil internally.
Same thing with the valve in question. Do any of the lines heat up quickly when trying to build pressure. If yes that again points towards flow being relieved under pressure creating heat.
Did the loader work before you changed the hoses?
When starting from ambient temperature does that pump housing get hot quickly vs pump inlet line when trying to build pressure? If yes the pump is potentially slipping or bypassing oil internally.
Same thing with the valve in question. Do any of the lines heat up quickly when trying to build pressure. If yes that again points towards flow being relieved under pressure creating heat.
Did the loader work before you changed the hoses?
Thanks so much for your input... From what I can search - most all these small tractors run at 2000 to 2500 psi. Yes - the loader worked - well enough to sell it to me - Without weight on it..
Some hoses were leaking and really looking weathered/bad - and I thought it would be a matter of a couple new hoses. NO fittings to fit anything on this tractor in Oklahoma, maybe nowhere but China. So I replaced all hoses and hard lines with hoses. The banjo fitting that connect to the cylinders and to the control valve were the only fittings the hose company had, or could get... So... All new. Heating up: Running at 1500 rpm - raise/lower FEL nothing gets hot at all. Pump - line - valve - nothing. all stays cool.oldnslo
Super Member
If the pump nor valve in question are getting hot I would not suspect either of them to the pressure limiting item.
Probably dumb question but how and where are you measuring the pressure? Did you tee a gauge into the pressure line and then operate a loader function to end of stroke or plugging the gauge into one on the loader lines?
Just curious if you get same pressure on raise - lower as you do on curl - dump. Long way of asking if possible your lift cylinders piston seals are leaking.
Probably dumb question but how and where are you measuring the pressure? Did you tee a gauge into the pressure line and then operate a loader function to end of stroke or plugging the gauge into one on the loader lines?
Just curious if you get same pressure on raise - lower as you do on curl - dump. Long way of asking if possible your lift cylinders piston seals are leaking.
I disconnected the line going to the loader lift cylinders and hooked up the gauge there. Then used the control valve to try to raise the loader to pressure the gauge. When I bought it - one of the lift cylinders was shot - would raise the bucket, but not with me standing in it. A curl cylinder was shot since it would leak off (uncurl). So all cylinders have been rebuilt. Everything works now - does not leak off - just doesn't have much lift capacity. 200 lbs and you would not think anything is wrong with it. 300 lbs and it struggles to lift it. The owners manual says it should lift 750 lbs or more.
When checking the curl cylinders, I disconnected a hose off a cylinder and moved the control valve to see if there was pressure - and it ran out the hose, fast - but I was expecting it to shoot across the yard. If pump is not the issue Then I suspect the valves in the picture... Just don't know what the purpose of the one is that has a small line going back to the pump.
When checking the curl cylinders, I disconnected a hose off a cylinder and moved the control valve to see if there was pressure - and it ran out the hose, fast - but I was expecting it to shoot across the yard.
If pump is not the issue Then I suspect the valves in the picture... Just don't know what the purpose of the one is that has a small line going back to the pump.