Hydraulic help on Satoh Beaver after pump replacement

[lomarker]

Hello,

I just finished installing a new (used) hydraulic pump on my little Beaver tractor. I filled the new pump with h-oil and started and still have no hydraulics. I am going to try and replace the O-rings at each location and try again, but is there something else I need to do to prime the system? The oil level is good and I've cleaned the filter. Any ideas would be great, thanks.

Steve

 

[JC-jetro]

Hello,

I just finished installing a new (used) hydraulic pump on my little Beaver tractor. I filled the new pump with h-oil and started and still have no hydraulics. I am going to try and replace the O-rings at each location and try again, but is there something else I need to do to prime the system? The oil level is good and I've cleaned the filter. Any ideas would be great, thanks.

Steve

Steve,

Do yo have live hydraulic? is the pump external? is it gear driven? is the pump lower than the sump ? Do you have Inlet screen in diffy additional to cartridge filter? do you have banjo connection at each inlet and discharge port of the pump?

How did you fill the new pump with Hyd fluid?

JC,

any pics?

 

[lomarker]

Hey JC,

I will try and answer your questions, thanks for the assistance.


Yes the tractor, although old, does have live hydraulics...I believe that just means I can move the bucket or whatever independent of the clutch/transmission. The pump is external and mounts on the exhaust side in the front near the fan. I think the pump is probably a little bit higher than the sump, but I'm not exactly sure what the "sump" is. There is a "banjo" type connection on both sides of the pump. The line coming into the top is larger than the line leaving the bottom. To fill I just used a funnel and put fluid in the pump...bumped the starter a few times to rotate and then added a bit more, no idea where the fluid actually went. I will try and figure out a picture or two, thanks again.

Steve

 

[JC-jetro]

Hey JC,

I will try and answer your questions, thanks for the assistance.


Yes the tractor, although old, does have live hydraulics...I believe that just means I can move the bucket or whatever independent of the clutch/transmission. The pump is external and mounts on the exhaust side in the front near the fan. I think the pump is probably a little bit higher than the sump, but I'm not exactly sure what the "sump" is. There is a "banjo" type connection on both sides of the pump. The line coming into the top is larger than the line leaving the bottom. To fill I just used a funnel and put fluid in the pump...bumped the starter a few times to rotate and then added a bit more, no idea where the fluid actually went. I will try and figure out a picture or two, thanks again.

Steve

Steve,

You have live hyd pump so any time engine is on you have flow. Your pump is for sure a gear driven and it is the same type of set up I have shown in the pics below. The pump is sort of positive displacement pump but has a hard time sucking air from the inlet pipe. Since your sump (the diffy Housing ) inlet lower to where the pump inlet inlet gravity can not help much with the priming of the pump. if the gears are okay and you have a bit of oil in it it should take a minute or so for the pump to be primed. to hasten that you can get the squirt bottle or funnel and fill the inlet pipe to the pump. the inlet pipe is always the larger dia pipe and discharge is the smaller dia pipe. Put the banjo connection in. If the banjo oring are in terrible shape there is outside chance it is sucking air causing the pump to cavitate or loose prime. give it a minute and it should start working. You should not loose prime once the pump is flooded.

 

[lomarker]

Thanks for the pics and assistance. I think I have everything put together properly, repalced O-rings and have absolutely nothing. I changed fluid again and cleaned filter, blew out inlet line. Pump seems to be moving just looking in inlet hole when started, and looking in the fill-hole in the case fluid appears to be cycling and spraying all over...but when I move any of the hydaulic levers, nothing. Could something be stuck or plugged or an air bubble somewhere or maybe the pump is bad? I have no ideas. Thanks again.

 

[Kernopelli]

You know, the problem could be something other than the pump. I wonder if you may have a small piece of debris stuck in the hydraulic control valve. I have had this happen before on a Mitsubishi tractor I once owned. As a matter of fact, yesterday I was doing some dirt work for a friend and my 3 point hitch quit working suddenly (FEL still works fine though). I haven't had a chance to look at it yet but I fully expect that I will find a little piece of something in the 3 P.H. valve. It could either be blocking an orifice or holding something (like a relief) open.
Something you may want to explore, especially since you have already repaired your pump.

 

[JC-jetro]

Thanks for the pics and assistance. I think I have everything put together properly, repalced O-rings and have absolutely nothing. I changed fluid again and cleaned filter, blew out inlet line. Pump seems to be moving just looking in inlet hole when started, and looking in the fill-hole in the case fluid appears to be cycling and spraying all over...but when I move any of the hydaulic levers, nothing. Could something be stuck or plugged or an air bubble somewhere or maybe the pump is bad? I have no ideas. Thanks again.

We have not established if the pump is pumping. can check for flow and pressure to see if you have them both. Dirt in the valve can be a reason , but why now? why did you change the pump in the first place and what are the events leading to this, that may give some tell tale signs.

JC,

 

[J_J]

In most cases, after filling the filter and pump, crank the engine without starting until all the air is purged out of the system. You should be able to hear a different sound when it starts to pressurize. You may have to do this procedure several times, and that is assuming that every thing in the suction path is tight. Once the fluid is under pressure, it will force any air out of the system. You should cycle every valve you have to purge the hyd lines..

 

[lomarker]

Thanks for the help guys. I replaced the pump due to the hydraulics gradually weakening. I had the system tested and it was putting out 300 psi. Went from having no issues to gradually not being able to lift the bucket with any load. The system still worked normally before taking the old pump off, except that had very lower pressure (power).

So, I bought a used hydraulic pump and installed it...which leads me to my current issue. I started and stopped everything multiple times and cylced all the controls. Tried point the tractor up a hill and then down a hill to remove any bubbles, but no changes. Where or what is the control valve and how would I check out. I'm hoping its not the used pump that I bought and that it is no good. I may try putting the old pump back on tomorrow to see if I get the same results...or may have to wait until my next day off.

Not sure what else to try. I'm certainly no expert in hydraulics, guess I should have paid closer attention in college. Thanks again.

 

[JC-jetro]

Thanks for the help guys. I replaced the pump due to the hydraulics gradually weakening. I had the system tested and it was putting out 300 psi. Went from having no issues to gradually not being able to lift the bucket with any load. The system still worked normally before taking the old pump off, except that had very lower pressure (power).

So, I bought a used hydraulic pump and installed it...which leads me to my current issue. I started and stopped everything multiple times and cylced all the controls. Tried point the tractor up a hill and then down a hill to remove any bubbles, but no changes. Where or what is the control valve and how would I check out. I'm hoping its not the used pump that I bought and that it is no good. I may try putting the old pump back on tomorrow to see if I get the same results...or may have to wait until my next day off.

Not sure what else to try. I'm certainly no expert in hydraulics, guess I should have paid closer attention in college. Thanks again.

Having low pressure at the spool valve is not always indicative of a bad pump. All hydraulic pump/system have some type of main system safety relief valve. the purpose is not to dead head a positive displacement type of a pump. tremendous pressure is caused by blocking the flow and it something has to give. the main hyd relief valve has that responsibility. if the main relief valve is stuck open due to contamination or mis adjustment of the spring can give impression of a bad pump. where did you measure the pressure on original setup? You r main flow pressure relief should be located downstream of the discharge piping out of the pump before it enters the control valve spool. can you identify that?

JC,

PS. I certainly feel more warm and fuzzy overhauling my own old pump, or at least tear the old pump open for inspection before buy and install a pig in a poke pump from a junk yard, no telling what life story your second pump had. Overhauling a gear pump is not difficult as long as gears or bushing were not damaged.