Ford 1700 Hydraulic Pump

[JC-jetro]

Fixing to check flow. I did pull the plug, started the tractor and at idle no fluid came out. Held my finger over the hole and sped it up, it took a few seconds before the fluid arrived but I was able to keep the fluid at bay with my finger. I will go into Houston tomorrow and get the gauge but I really don't think it will much pressure. Of course when the pressure did start building, I pulled back on the throttle. Keep you posted

okay. Pressure and flow are two different things. 1000 psi and .1 gall is a whole different animals at 1000 psi and 6 -7 gallons. What happens when you lower or raise the lift arm. I'd put the plug back in , lower or raise the left arm at exceedingly higher rpm up to 2500 engine rpm. I hope that might displace a blockage... only hoping. Does your lift arms go up and down ? is the lift arm attached to any implement? what happens when you lift the arm all the way to the highest point( the built in notch bracket)? what happens if you go beyond that? Do you hear a chatter coming from the main pressure release safety valve I pictured before?

JC,

 

[hgd1956]

Pressure and flow results:

Pressure at high rpm - Won't even register on my 0-3000 psi gauge

Flow - 2 liters a minute ~ 1/2 gallon

Yes 3 point hitch will raise and lower but only with no weight on it and it very slow at high tractor rpms.

No 3 point hitch will not raise if the rpms are just below max

Dropped hydraulic fluid again and check suction screen hoping to find some junk on it, no luck, clean, clean, clean........................

Where to go from here? My pump had a little wear but nothing terrible, having worked for Chevron for 30 years I have seen gear pumps in much worse shape put up more flow and pressure than this thing. Now I am wondering if I had a slip in the oring area when assembling the pump, would be easy with those crappy little mustache looking orings.

I do know now that the lift piston must be in pretty good shape to operate at all with such low flows and low pressure! I would buy a new hydraulic pump if I could just find one for a reasonable price. No luck yet locating one. Any ideas?

 

[svcguy]

I would go back to your pressure relief valve and ensure it isn't stuck open. Something sounds like it is spilling over.

When you 'buffed' the aluminum, did you use a piece of plate glass to ensure an absolutely flat surface? We plane them on a milling machine to remove wear, as tolerances are pretty scant when it comes to hydraulics. For example, a properly fitting spool in a hydraulic valve is so sensitive that if you hold it in your hand and warm it up to body temp and the valve body is cold, the spool may not fit back into it. The pressures in a pump are such that you need to ensure for absolutely flat surfaces. While I doubt that is what is doing it, I have seen pumps spill over half their capacity due to worn end plates.

 

[JC-jetro]

Pressure and flow results:

Pressure at high rpm - Won't even register on my 0-3000 psi gauge

Flow - 2 liters a minute ~ 1/2 gallon

Yes 3 point hitch will raise and lower but only with no weight on it and it very slow at high tractor rpms.

No 3 point hitch will not raise if the rpms are just below max

Dropped hydraulic fluid again and check suction screen hoping to find some junk on it, no luck, clean, clean, clean........................

Where to go from here? My pump had a little wear but nothing terrible, having worked for Chevron for 30 years I have seen gear pumps in much worse shape put up more flow and pressure than this thing. Now I am wondering if I had a slip in the oring area when assembling the pump, would be easy with those crappy little mustache looking orings.

I do know now that the lift piston must be in pretty good shape to operate at all with such low flows and low pressure! I would buy a new hydraulic pump if I could just find one for a reasonable price. No luck yet locating one. Any ideas?

Hmmm, the plot thickens
-I know you have done the inlet screen and we know for sure it is clean but how about the inlet pipe from the screen to pump inlet... you reckon there might be blockage there needing angioplasty?
-Did you check in to the main relief like I pictured before, if someone let it run above the set point cause the relief valve to lift repeatedly and destroy the valve or seat causing much by pass? How about the spring there is busted?
-there is also a check valve in the cylinder head that is used for shock relief. if that is open you'll have no chance of building good pressure.

This is the opposite of where you put the gauge.



The stiff long spring and the ball is for relief of shock loading to the lift piston and seal.



- The mustache looking seal only causes damning up some lube for the gear shaft in the bushing. pump flow is made between the gear and the case. I hope the case or the gear are not worn that bad. if you want to see the picture of them and how they are oriented let me know.

-taking the lift piston head takes less than 10 minutes. might not be a bad idea to have a look at the seal. you can put it back without replacement or damage to anything.

At this point I lean more toward the main pressure relief and hopefully some blockage in the inlet tube or may be even the banjo fitting. Probably a sucked in oring in the banjo fitting would not be good. Pump working with a such a low flow and pressure is good possibility of inlet blockage.

let us know what you find out.

JC,

-

 

[hgd1956]

I too was worried about sucking in some air through one of the suction connections. I pulled them yesterday and made sure all were in good shape. But before pulling, I checked to see if there were any leaks at all to indicate a leak, dry. SVC Guy...........I have been worried about the clearance of the pump gears and the end plates, I did use a good flat surface while buffing the end plates but there does seem to be a little thrust movement of the gears themselve after reassembly. I could understand losing some of my flow and pressure due to this happening but no pressure at all. I did pull the outlet line from the pump and it does pump fluid with no resistance and it will lift the hitch even with no real pressure showing (without any thing attached and the engine rpms high). JC.........I will pull that other relief valve today and check it out, I pulled the primary one early on and it seemed to be ok, however, even if it were leaking, the orifice is so small I would still show some pressure if it were leaking. The journey continues...........I paid 1000 for this tractor and I have almost doubled my investment. Don't mind if I can just get it working correctly.

After working on this little misfit, I just get into my New Holland TD 80D turn the air conditioner up and listen to a little music while mowing. Life returns to normal. Thanks for the help...........

to be continued

 

[JC-jetro]

I too was worried about sucking in some air through one of the suction connections. I pulled them yesterday and made sure all were in good shape. But before pulling, I checked to see if there were any leaks at all to indicate a leak, dry. SVC Guy...........I have been worried about the clearance of the pump gears and the end plates, I did use a good flat surface while buffing the end plates but there does seem to be a little thrust movement of the gears themselve after reassembly. I could understand losing some of my flow and pressure due to this happening but no pressure at all. I did pull the outlet line from the pump and it does pump fluid with no resistance and it will lift the hitch even with no real pressure showing (without any thing attached and the engine rpms high). JC.........I will pull that other relief valve today and check it out, I pulled the primary one early on and it seemed to be ok, however, even if it were leaking, the orifice is so small I would still show some pressure if it were leaking. The journey continues...........I paid 1000 for this tractor and I have almost doubled my investment. Don't mind if I can just get it working correctly.

After working on this little misfit, I just get into my New Holland TD 80D turn the air conditioner up and listen to a little music while mowing. Life returns to normal. Thanks for the help...........

to be continued

Keep on chugging buddy one question you did not answer was when you took the plug off and while engine was running and you wqere getting couple of liters of flow. In that fix did you raise or lower your lift arm handle on the spool valve ? I wonderd if that effected the flow. Now, if you have the lift arm all the way down, with the plug in the spool should divert 100% of the flow back to diffy, at that point pressure inspection out of relief device is done totally bypassing the spool valve. I wonderd if you get more pressure there

 

[svcguy]

I would find someone who knows that particular pump who can advise on clearances. It is unusual to have much end play. I had a Volvo T800 that had low pressure and shaving the end plates and body brought it pretty much back to spec. There has to be more happening to your pump though, as it still doesn't explain the total loss of pressure.

 

[hgd1956]

No additional pressure during with the lift engaged or not. After replacing the fluid yesterday, I rechecked the flow and got a whopping 1 gpm while still no pressure showing. I also pulled the other relief valve and made sure everything was working ok. The pump has to be the culprit, the only way to get it primed (even with a preprime of 80 weight gear oil is to open up the discharge line a little allowing some of the flow to drop into a bucket. I am going to try to find some place to go through the pump and rebuild it to original tolerences. Keep you guys posted...............

 

[JC-jetro]

No additional pressure during with the lift engaged or not. After replacing the fluid yesterday, I rechecked the flow and got a whopping 1 gpm while still no pressure showing. I also pulled the other relief valve and made sure everything was working ok. The pump has to be the culprit, the only way to get it primed (even with a preprime of 80 weight gear oil is to open up the discharge line a little allowing some of the flow to drop into a bucket. I am going to try to find some place to go through the pump and rebuild it to original tolerences. Keep you guys posted...............

Sorry to hear that buddy, the mustache looking seals have little to do with building pressure, they act as sort of internal relief, flow by pass to lube the gears shafts in the bushing and thats's all. what causes the pressure is very close tolerant of pump case, gear surfaces and a good film coefficient. I don't reckon you can add material to pump case and then mill it to specs. When I put my pump together after overhaul, the tolerances were so tight I could not by hand pressure turn the pump input shaft.

JC,

 

[old1500]

I will keep this particular thread busy, since we are talking hydraulics. My 1500 is about the same thing...we all know that. Yesterday, my lift threw a little fit. It would "chatter" and slowly raise, but would not pick-up the load I was working with fully. Under no load, it would go up and down, but chattered on the way up. I fooled with it for a while and completed the task I was doing and went to take a look at it this afternoon....it's working fine now????

I had recently drained and replaced the fluid and cleaned the filter screen. One thing I did not do correctly (I hope) is purge the system. There is a small vent-screw on the top of the filter canister, which I opened a time or two and operated the lift, but nothing ever came out of this hole. Maybe some air, but no fluid and I assumed this was what the screw was for. What's up with that....if I had that screw backed-out a little, would I not have had some fluid coming out?

What is the correct procedure to purge it? I am thinking I had some air pass through the system, but I was sure I could get some fluid to come out of the top of the filter canister...should I?