Ford 1700 Hydraulic Pump

[hgd1956]

I have a 1979 Ford 1700. I bought it as a basket case and it have proven to be a real challenge getting in running shape. I managed to get it all together only to find that the hydraulic pump is very weak. No real pressure and the flow is low as well. When I bought the tractor it had been sitting for about 6 years apparrently outside. I have pulled the pump and disassembled it only to find that it has been damaged internally and needs to be replaced or repaired. This is the problem, New Holland has a new pump, 845 dollars or a rebuild kit that only addresses the seals and such, no internal parts. Also, it appears that the early 1700s had a bigger pump than the later models. I ordered a used pump from LCI and of course it was the smaller later model. Help Please...........................this thing is killing me!

 

[JC-jetro]

I have a 1979 Ford 1700. I bought it as a basket case and it have proven to be a real challenge getting in running shape. I managed to get it all together only to find that the hydraulic pump is very weak. No real pressure and the flow is low as well. When I bought the tractor it had been sitting for about 6 years apparrently outside. I have pulled the pump and disassembled it only to find that it has been damaged internally and needs to be replaced or repaired. This is the problem, New Holland has a new pump, 845 dollars or a rebuild kit that only addresses the seals and such, no internal parts. Also, it appears that the early 1700s had a bigger pump than the later models. I ordered a used pump from LCI and of course it was the smaller later model. Help Please...........................this thing is killing me!

Been there, done that !!! I would not lose hope just yet. Please read the link below. It might be more read that you might like but passed the list seal the rest is pump stuff. Take pictures of the gears, and inside of the pump case and report back. There might be some tell tale sign that we might find. A repair seal kit along with a separate shaft seal might do the trick in lieu of $850 pump. You might have dirty screen leading to low gpm. How did you figure out your gpm? report back with your finding and we'll help.

JC,


http://www.tractorbynet.com/forums/new-holland-owning-operating/90819-my-f-1700-testing-my.html

 

[hgd1956]

Since my last posting I have learned a few things. First, the damage inside the pump was very minor. I buffed the aluminum pieces to remove the light marks and reinstalled the gears. After reading you entire posting, I realized that my seals were toast and they were probably the culprit. I ordered the seal yesterday and will get them in a couple of days. Back to your other questions, when I got the tractor it was full of water in the transmision. I dropped all of the transmission/water fluid flushed then replace with fresh. Of course, I had a brain fart and did not check the suction screen, so I dropped it again and pulled the screen. It was clean as a whistle. More new fluid and still no 3 point hitch.................I then dropped the discharge line from the pump and started the tractor which assured me that the pump was primed. By timing the flow into my bucket It was easy to determine that my pump was not performing well at all. The flow was around a gallon per minute. That is when I pulled the pump and arrived at this point. HD

 

[JC-jetro]

So far so good... Not bad aye. make sure to change pump input shaft seal as well. It is about $10 if I remember it right. That might allow air to be sucked in causing priming loss. On mine actually the shaft seal was the culprit. As long as the pump is not running dry there still be hope. make sure to orient the seal inside right as they will cause a bypass flow to keep the bushing and shaft lubricated. One way that you can check the flow in a cleaner manner and also checking your spool valve flow is directed to hose attached where I have a P. gauge in the pic below on lift piston cylinder head. Use a bucket to capture the fluid. Lift arm up and flow, lift arm down all the way no flow. I'm optimistic you'll fix it. Report back with your progress.

JC,


Edit;Once you get the pump working like it should and no 3 points, then you still might need to change the lift seal. even at reduced pump flow it the lift should still work but slow and not robust. Seal change was also on my posting and is a simple task. Spool valve operation is important as you can easily check it like how I suggested above.

 

[old1500]

I have a 1500, but I think we are like....sisters or something. So many components will interchange with the 1700. We have to be close-kin.

I have a "jerky" 3PH. It works, but a bit jerky on the up-swing with a load on it. I have it down working on something else, but went ahead and replaced my hydro-fluid. Mine has a strainer-cup right on top of the pump and when I pulled it....it looked like a family of mice had been living in there. I cleaned the filter (mesh) screen real well and noticed there was no o-ring at the base of the cup. I says....surely you must have dropped it, but nope...no o-ring to be found anywhere. I do not think it had been leaking as I have never noticed a greasy-spot on the shop floor. I don't know if any air could have been getting into the system from this connection, but I would suppose it would have been a leak under high pressure and no air could get in. My cylinder has had the seal replaced by the previous owner, at least the invoice he gave me when I bought the tractor it said the dealer did anyway.

I am hoping for smoother performance after a fluid change and filter clean...we'll see. Yes...I did put an o-ring back on the cover.

 

[hgd1956]

OK...........the hydraulic pump is rebuilt with new orings and seals installed and no improvement occurred. I can rule out my pump as the problem because it is in as good of shape as yours JC. I don't have a gauge to check the pressure but I feel sure it is low. My repair manual points to the unload valve assembly as the possible culprit. I can not find the little bugger! Is it inside the case behind the relief valve assembly? The book indicates that if that unload valve sticks open, then all of the fluid will just return to the crankcase and nothing goes to the lift cylinder. How do I get to it?

 

[JC-jetro]

OK...........the hydraulic pump is rebuilt with new orings and seals installed and no improvement occurred. I can rule out my pump as the problem because it is in as good of shape as yours JC. I don't have a gauge to check the pressure but I feel sure it is low. My repair manual points to the unload valve assembly as the possible culprit. I can not find the little bugger! Is it inside the case behind the relief valve assembly? The book indicates that if that unload valve sticks open, then all of the fluid will just return to the crankcase and nothing goes to the lift cylinder. How do I get to it?

A northern liq filled gauge from Northen is under $20 and it works fine for the price. Pic below shows the inside of the lift cover where you see the back of the spool valve. Look at the feed back arm that is externally attached to lift arm. That feed back arm returns the valve to neutral position at any given lift height, basically returns the fluid back to the rear diffy immediately below.



The feed back link on the outside. it goes thru the lift cover and ties in to the spool.



I would not just take the spool off and start tearing in to it as the replacement guts of it might be difficult to come by. Do all non destructive facts finding before tearing in to the spool, innards might be very expensive.

Do yourself a favor and invest in a gauge, one time use will pay for it self.

You might have a relief mechanism for your 3 point sets to a very low pressure causing most of the oil going in to the diffy rather than lift.





Did you do the flow test from my previous post?

JC,

 

[hgd1956]

Not yet.....I will go try to find a fitting and short hose to check the flow into a bucket. I am going to go over to Northern Tool and pick up a gauge as well. Keep you posted

 

[JC-jetro]

Not yet.....I will go try to find a fitting and short hose to check the flow into a bucket. I am going to go over to Northern Tool and pick up a gauge as well. Keep you posted

This is what I bought. Seems to be built well for the price.

JC,

Valley Instrument Grade A Stem Mount 2 1/2in. Glycerin Filled Gauge — 0-5000 PSI | Filled Gauges | Northern Tool + Equipment

 

[hgd1956]

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

 

[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?