My F-1700 testing my patience

[JC-jetro]

Well, this tractor is giving me a run for the money. I like to take up a challenge every once in a while but this thing is keeping on giving me a new one just too frequently .
Just quick excerpts.
Bought a 1979 Ford 1700 (First time owner, pretty green )in good mechanical shape (anything that naked eye could confirm), No rust , kept inside , engine started right up, no oil burning, 3 point hitch worked ( went up and down as commanded and stayed where I told it to stay). I changed all the fluid but transmission/Hydraulics and lubed it good. Bought a carry all, put floor and side and took it to the field. It worked great for a while, .but then,….


First problem: 3 point started act squirrelly, would not go up or down as commanded, would decide on its own when to do it, I checked relief off the pump discharge and the lift piston and all checked out. Checked the inlet screen on pump intake and it was badly clogged with residue of old oil (20 years) and no metal shaving. I cleaned the screen , put all togetehr with new oil and she perked right up to the point I did my first project of making 3-point boom and went to the field. I ended up having all kind of power and started having fun. Pulling a six inch 40 yr old post was like pulling tooth pick our of butter.





Second problem: Unfortunately my elation was short lived. I had all the hydraulics power when the engine was running but as soon as I turned the engine off the 3 point would go limp on me quickly. I reckoned I had a leak of some sort internally in areas such as relief valve, spool valve or piston seal. First two checked out okay. I took the cylinder head off, removed the lift cylinder and piston and “voila” piston seal had seen better days. I'm sure that is the original 20 year seal. Any how, changed the seal, put all together and start the tractor and 3 point promptly comes up and stays up with the engine shut. I turn the engine on again, and up and down we go and, she responds quickly. I go to the field and work for 6 Hours and keep hauling and skidding lumber. After lunch I lower it a tad bit to load something heavy, she comes down but when I tried to rise her back, she refused with no inclination to even try. I did not like that a bit. Refrained to lower 3 point any further as I needed to take the tractor back to the barn with the cargo.






The fact that hitch stays up when I ask it indicates to me that piston seal installation is done right, spool valve holds tight and piston relief is not prematurely opening up. I went to the barn a bit gloomy, checkd the relief valve for some restriction and it’s okay, open up the pressure relief port (on pistion head) by taking the valve body and all and then started the engine, dang … no oil coming out with engine running. Then I took the relief assembly on pump discharge pumping out , put a bucket undeneeth and started the tractor. I do get some flow but can not quantify pump flow or pressure quality of the oil. At this point, I think the seal on the pump that is the same vintage of the lift cylinder has come to the same fate, and the reason I had some flow is just gears doing some pumping with no back pressure. I think the pump had to battle more of restriction and copuld not cope having seals probably sma shape of piston seal and for sure the same age.




I have ordered the pump seal kit and looking for some free time to get the pump overhauled. Can anyone chime in with some word of wisdom? I reckon I have done everything in a logical manner and nothing I have done could have caused the problem. I also think may be with new piston seal the pump had to content with more pressure and gave out but “How come I could lift the post out of the ground with the same pump without a peep?”

 

[Hooked_on_HP]

I would guess you pluged the filter again. There is another drain plug under the draw bar. If you missed that one you left about 5 gal. of old oil in it. My 1900 was giving me hyd. problems when I first got it. I ended up changing the hyd. oil 3 times before I got everything flushed out and clean.

 

[JC-jetro]

I would guess you pluged the filter again. There is another drain plug under the draw bar. If you missed that one you left about 5 gal. of old oil in it. My 1900 was giving me hyd. problems when I first got it. I ended up changing the hyd. oil 3 times before I got everything flushed out and clean.

No. I know the differential drain in the back. On top of that I made a vacuum siphon collection can sining my shop vac and sucked out 3 quarts of thick snot right out of the bottom floor of differential. This was after I used a piece of bailing wire and pulling the stuff out of bottom drain in the differential. I used the opening left after I withdrew the filter strainer section to vacuo suck it clean. This the way the inside of differential looks like.

 

[Hooked_on_HP]

When you raise the tph do you hear the pump groan or any thing. Could the poppet in the control be stuck. Have you tried unhooking the rod that goes to the control and checking your releif pressure. I beleive somthing is letting the oil bypass. Does the tractor have power steering and if so does it work properly. If it works the hyd. pump is pumping.

 

[JC-jetro]

When you raise the tph do you hear the pump groan or any thing. Could the poppet in the control be stuck. Have you tried unhooking the rod that goes to the control and checking your relief pressure. I beleive somthing is letting the oil bypass. Does the tractor have power steering and if so does it work properly. If it works the hyd. pump is pumping.

All very good point.

1. When I raise the 3 pt to the maximum point I should exceed relief pressure setting , hence having the main relief the chatter and relief. I was able to cause that when the pump was flowing properly.

2. I have not actually measured the relief pressure setting but I removed the relief device entirely off of the tractor, turned the tractor on and even with manipulation of the 3 point had no flow. I cannot see the spool valve to %100 by pass fail when it was able to hold the 3 points up (I.e not leaking check valve)

3. I have no power steering so no chance of losing fluid to a different system.


Now I totally removed the main pressure relief valve off of pump discharge pumping and was able to get some low flow out of pump. I postulate that at that point I was operating a gear pump with a very bad seal pumping against no head by sling the flow in to the piping. I think I have a pump that can not pump against any head. I ordered the pump seal kit and will attempt repairs.

 

[dqdave1]

Sounds to me that you are doing everything correctly. The contaminated oil is taking its toll. Hopefully, third time is a charm.

 

[Hooked_on_HP]

Do you have a service manual.This is a verry simple gear pump.To have no pressure at all the pump would have to be in real bad shape. In the manual they tell you to check the wear pattern on the housing. If it goes more than 3/4 of the way around replace the pump. This is a $700 pump from NH. I hope you find something else wrong.

 

[JC-jetro]

Do you have a service manual.This is a very simple gear pump.To have no pressure at all the pump would have to be in real bad shape. In the manual they tell you to check the wear pattern on the housing. If it goes more than 3/4 of the way around replace the pump. This is a $700 pump from NH. I hope you find something else wrong.

Yes, but the cheesy $26 one. it is adequate. it is indeed a simple pump. I will inspect the wear pattern but these type of gear pumps are built tough. The seals and O-rings are really the only expendables though. If you had metallic particles, sand contaminant then you wiould have damage for sure. The inlet screen is really a very fine mesh. It is much finer that my shaving machine screen. There were no sign of any metallic foriegn material in the old oil. the oil that was settled in the bottom of the differential had the consistency of cheese curd and jello like material. The funny thing oil in the transmission by inspecting the dip stick did not look all that bad. I get the parts in couple of days. In Kansas deer season is right after thanksgiving , so I got to get my ducks in a row to avoid missing any action. As soon as I get time ,I'll work on the repair and update and post picture of the result. I reckon pump seal will look dry and crumbly and hard just the way lift cylinder seal looked like in the pics posted earlier. Thanks all for the good inputs.

 

[JC-jetro]

Hello all, Just an update. I took the hydraulic pump off, took it apart and frankly did not find anything that looked very wrong. The bushing seals looked okay. I reckon they help lubricating the gear shaft. The case seal (O-ring) also looked good. The pump shaft seal did not look that bad , may be just a bit dry. The gears looked good and no metal abrasion of the pump casing at all. Any how, bought a seal kit for $40 from NH dealer. it is noteworthy that the gasket kit does not include shaft seal. I bought it separately $12.

I thoroughly cleaned all components, lubed it good, and assembled the pump. today I took it to the farm and reinstalled it, took no more than 30 minutes. started the tractor and after 20 second of pump trying to prime the pump came back to life. I can now raise and lower the 3 pt at will. I'm happy now .

I was able to raise a heavy woods brush hog with no problem. My relief works as I lift to the highest position. I will try to get a liq filled gage to measure the relief pressure setting. I reckon after I replaced the lift cylinder seal, then the pump had to work extra hard and it blew the shaft seal. It may be that my relif is set too high. I will check it. I think the problem was the shaft seal on the suction side of the pump. Most likely it sucked some crankcase air in cavitatiing the pump rather than blowing hyd oil in to the crankcase thru timing chain cover. It seems I have overhauled the whole hydraulic system other than the spool valve. Hopefully it'll work for a while. All the components I changed were about 27 years old and never been changed.

I hope I will not have anymore challenge for a while.

Removing Pump.




Pump Components

 

[gsxrsquid]

Well done!