Hydraulic help on Satoh Beaver after pump replacement

lomarker · Aug 28, 2008

Hey JC, I'm not sure where they tested the system, I just dropped it off at a little tractor shop and that was the result they gave me. My next day off I will have to dig deeper into the control valve and see what I can come up with. I'm assuming all of these parts are "underneath" the seat in the hydraulic case.

I would have liked to rebuild the OE pump, but it was not something that seemed feasable with way the allen bolts are notched to prevent removal. Maybe it will end up the pump is ok and I can send the other one back. Thanks.

Steve

JC-jetro · Aug 28, 2008

lomarker said:
Hey JC, I'm not sure where they tested the system, I just dropped it off at a little tractor shop and that was the result they gave me. My next day off I will have to dig deeper into the control valve and see what I can come up with. I'm assuming all of these parts are "underneath" the seat in the hydraulic case.

I would have liked to rebuild the OE pump, but it was not something that seemed feasable with way the allen bolts are notched to prevent removal. Maybe it will end up the pump is ok and I can send the other one back. Thanks.

Steve

Steve,

If you follow the discharge pipe out of the pump to where it ties to control valve you'll be able to see some sort of main pressure relief valve. A lot of Japanese made and designed tractor share the same design. this relief valve is before hyd flow goes to lift control valve spool, so the system will not be damaged in case of dead heading the pump due to various reasons.

below you see the stiff spring and som means of adjustment of pressure either by an asjuting nut or by adding washers to add to spring stiffness. If the adjustment is dorked up bad or the valve is stuck open by a piece of debris then you can not maintain much flow and pressure. the system pressure should be measured downstream of the relief valve and not upstream of it to give a measure what pressure the relief is maintaing

JC,

lomarker · Aug 31, 2008

Thanks again for the help guys. I had some time after work to wrench on this thing some more and did the following:

Blew out all the hydraulic lines, found the control valves cleaned everything, found the relief valve and made sure it was good, changed all O-rings in the system. Put it all back together with the new (used) hydraulic pump and still nothing. So...re-installed the old pump and things are the same as when I took pump off, I have hydraulics, but real weak...won't even lift the front wheels off the ground...but at least I know everything is still working and it has to be the new (used) pump that is bad.

So I decide to take the new (used) pump apart to see what its all about and find an obvious problem, bad O-ring (see pics). I'm hoping that I can find a similar O-ring around here and replace it, or is that going to have to be a special order thing? The rest of the rings look ok, and the gears seem to turn ok. If I need additional parts and ideas where do I get parts for this pump...it is a JAPAN Shimadzu (?) I think. Has a few numbers inside (402-10754) on the thing outer piece and (402-10740-01) on the inside thicker piece and (11WA-001) on the outside piece near the attachment point for the pump.

I may try and take the old pump apart also. It looks a little more difficult to take apart thanks to the allen head bolts and the indentations to keep the bolts from moving. Any slick tricks for getting the allen head bolts out?

Thanks again for the advice.

Steve

JC-jetro · Sep 3, 2008

lomarker said:
Thanks again for the help guys. I had some time after work to wrench on this thing some more and did the following:

Blew out all the hydraulic lines, found the control valves cleaned everything, found the relief valve and made sure it was good, changed all O-rings in the system. Put it all back together with the new (used) hydraulic pump and still nothing. So...re-installed the old pump and things are the same as when I took pump off, I have hydraulics, but real weak...won't even lift the front wheels off the ground...but at least I know everything is still working and it has to be the new (used) pump that is bad.

So I decide to take the new (used) pump apart to see what its all about and find an obvious problem, bad O-ring (see pics). I'm hoping that I can find a similar O-ring around here and replace it, or is that going to have to be a special order thing? The rest of the rings look ok, and the gears seem to turn ok. If I need additional parts and ideas where do I get parts for this pump...it is a JAPAN Shimadzu (?) I think. Has a few numbers inside (402-10754) on the thing outer piece and (402-10740-01) on the inside thicker piece and (11WA-001) on the outside piece near the attachment point for the pump.

I may try and take the old pump apart also. It looks a little more difficult to take apart thanks to the allen head bolts and the indentations to keep the bolts from moving. Any slick tricks for getting the allen head bolts out?

Thanks again for the advice.

Steve

Steve,

Where you trying to lift the front wheels off with the FEL? How about your 3 point lift? can you lift the arms?

as far as the pump it looks good. on pic 0676 you can obviously see the inlet and outlet volutes. The oil gets trapped between the pump casing and gears and travels around to the discharge volute. That's where the compression(i.e pressure) starts to build up. The orings that you see take a portion of the discharge oil and meters it to the inlet (sort of safety by pass) and the rest lubes the gear shaft that turns inside the bushings. Closer inspection and you'll see friction bearing that get lubed by the bypass oil under pressure.
On pic 0678 on the bottom plate you see a shaft seal on the other side that is secured to the hole by a snap ring, that is indeed very important to make the pump work air leakage thru that or oil discharge can cause the pump not to pump. Buying a shaft seal is going to be more tricky than the the orings. If it were me and I've exhausted all efforts to buy an overhaul kit to no avail, at that point, I would do the following. I would clean the surfaces of the groves real well including all the oil film, I would take some RTV blue and cut the discharge nozzle to run a bead as close as I can get to the size of the oring dia. I would then leave it the heck alone for several hours for the rtv to skin and cure where is totally dry to touch and assemble the pump ... hoping for the best.

That would be my last resort, I'd give that a try before I give up. you do not want a lot of rtv to get in to the system and plug up any of the control valves that's why it is important for it to cure before you assemble the pump. If you mic the outer dia of the pump shaft and inner dia of the housing you may be able to duplicate a working a pump shaft seal.

JC,

Just FYI