Ford 1700 3 pt lift problem

Marinemammal · Oct 11, 2021

After several days of trying different plumbing arrangements, nothing seemed to work. I drained the oil and cleaned the screen, replaced the used (but clean-looking) oil and it worked fine--for about 20 minutes. This is confusing, because the screen looked clean (before cleaning it) as did the oil. Even after cleaning the screen, if I removed the banjo bolt at the screen, very little oil would run out--maybe a stream about 1/8 inch. After running for 20 minutes the hydraulics quit, and hardly any oil would run out with the banjo bolt removed. So I installed a 3/4 inch plastic threaded pipe in the banjo hole (it fits) and blew air back through the screen and everything worked again--for about 20 minutes. So I drilled a 3/8 inch hole in the end of the screen cylinder and everything works fine and it seems like it's going to stay that way. The loader is faster and better than ever.

I know this is not a good idea, but I didn't know what else to do. So my plan now is to get new oil, plug the drilled hole with a bolt and drill 1/16 inch holes in the end of the screen--36 of them if there's room. I would like to add an external oil filter on to the system, but don't know how to do it since all the external lines are subject to 2000 psi.

It's plumbed like this. Pump-----Loader-----Relief Valve (relieves to trans)-----Power Steering----Three-Point

As in my previously attached drawing...

JC-jetro · Oct 11, 2021

Marinemammal said:
After several days of trying different plumbing arrangements, nothing seemed to work. I drained the oil and cleaned the screen, replaced the used (but clean-looking) oil and it worked fine--for about 20 minutes. This is confusing, because the screen looked clean (before cleaning it) as did the oil. Even after cleaning the screen, if I removed the banjo bolt at the screen, very little oil would run out--maybe a stream about 1/8 inch. After running for 20 minutes the hydraulics quit, and hardly any oil would run out with the banjo bolt removed. So I installed a 3/4 inch plastic threaded pipe in the banjo hole (it fits) and blew air back through the screen and everything worked again--for about 20 minutes. So I drilled a 3/8 inch hole in the end of the screen cylinder and everything works fine and it seems like it's going to stay that way. The loader is faster and better than ever.

I know this is not a good idea, but I didn't know what else to do. So my plan now is to get new oil, plug the drilled hole with a bolt and drill 1/16 inch holes in the end of the screen--36 of them if there's room. I would like to add an external oil filter on to the system, but don't know how to do it since all the external lines are subject to 2000 psi.

It's plumbed like this. Pump-----Loader-----Relief Valve (relieves to trans)-----Power Steering----Three-Point

As in my previously attached drawing...

This is perplexing saying the least.

it seems the pump is having a hard time maintaining the prime. This is either suction restriction or pump gear to case not in tolerance causing slippage (oil)
with banjo removed at the screen you should have a stronger release of oil. That could be if your oil is too thick or screen blockage and yet your screen is clear after the inspection which does not make sense.
I think filter on the discharge side of the pump is a very bad idea and the reason you mentioned. More important than that is the purpose of the filter is to protect the pump and nothing else. With no filter in the suction you would run a risk of sucking junk and metal shaving in the inlet of the pump which obviously really bad.
You made a bypass by drilling a hole that in turn lowered the suction resistance and helped the pump to maintain the prime.
I would drill the holes on top of the screen rather than end or bottom, thinking crap would settle on the bottom of diffy and the oil 3 inches or so from bottom of diffy wold be inherently claner.

did you clean and inspect the floor of diffy after removing the screen? on mine i had a 1/2" thick layer of sludge the very first time I did the oil change. Perhaps it was the very first time ever for the tractor. My ford is 40 years old and I owned it in the last 16 years. The second time I did the oil change there were hardly any slime. I sure hope right oil would help your situation. just keep us posted with your progress. Good luck.

Marinemammal · Oct 13, 2021

I didn't try to clean it out--but should have. I have done a thorough cleaning of it not long ago. I am using the recommended oil--tractor hydraulic transmission oil recommended for Ford M2C 134-A. I did try to see if there was a viscosity difference between the used oil and the new oil by drilling a 1/8 inch hole in a soup can and timing the oil flowing out. It was about the same--3.5 minutes for about 10 ounces of oil.

I was using the cheaper 303 oil (due to all the oil changes) which may be a less viscous oil and it seemed to work longer before the hydraulic system quit--6 months to a couple years depending on use. Maybe I can find some new 303 and test it with my soup can.

One of the first symptoms of the hydraulics stopping working was that the bucket would not go down with the the tractor off. It would normally relax down after turning if off by pushing the lever. And since I don't believe that this action has anything to do with the screen on the pump intake, I don't know what to make of it.

JC-jetro · Oct 13, 2021

I didn't try to clean it out--but should have. I have done a thorough cleaning of it not long ago. I am using the recommended oil--tractor hydraulic transmission oil recommended for Ford M2C 134-A. I did try to see if there was a viscosity difference between the used oil and the new oil by drilling a 1/8 inch hole in a soup can and timing the oil flowing out. It was about the same--3.5 minutes for about 10 ounces of oil.

I think cleaning is for sure better, How much better?? can't tell you. Screen allows oil to filter out from all sides and since the filter is mounted horizontally in the diffy then I would think muck and crap in the bottom tends to collect to the bottom more than top to add more or less friction to oil flow. I like your approach to quantify things, comparing apples to apples with your can experiment.

I was using the cheaper 303 oil (due to all the oil changes) which may be a less viscous oil and it seemed to work longer before the hydraulic system quit--6 months to a couple years depending on use. Maybe I can find some new 303 and test it with my soup can.

I really hope the main culprit was wrong oil and by oil change it will only could get better. you have done several things to your pump and I hope it does not have intermittent issues.

One of the first symptoms of the hydraulics stopping working was that the bucket would not go down with the the tractor off. It would normally relax down after turning if off by pushing the lever. And since I don't believe that this action has anything to do with the screen on the pump intake, I don't know what to make of it.

The only thing that could be the reason is that the oil is trapped in that cylinder well and that is how it should be . Your particular issue really points the finger to loader control valve. The bucket generally should not come down if the control valve seals and cylinder seals are okay. if it goes down on it's on then it is a bit of seepage and leak of the piston or control valve. Here you said " bucket would not relax with the tractor off and lever pushed in", in this situation then there might be blockage in the return path. This is so difficult to pinpoint, just imagine if some piece of teflon tape used to put the taperd joint together and you have bits and pieces floating in the system. I just wonder what permanent or momentarily it can do to a hydraulic system that is pumping constantly and in your case around 5.3 gpm no matter what as long as the tractor is running.

Strikeout692 · Jan 21, 2023

rayikeo2 said:
JC I noticed in one of your earlier posts that you had pictures of the lift cylinder and piston when you replaced the seal. My question is when you take the 6 bolts off the piston housing does the cylinder and piston assembly come out with the housing? I have a shop manual but it does not go into detail about this. Also what is necessary to do to seperate the piston and how big a job is it to replace the assembly into the tractor after the seal is replaced. I figure since you have done this procedure you probably can pass along the do's and don'ts to get the job completed correctly. Ray

Do you happen to have the part number for the seal? Same issue here

Strikeout692 · Jan 21, 2023

ComputerGuy said:
I wish I had taken pictures now! It was a bit hard to be the mechanic and the photographer too! But yes, it was an O-ring and a nylon/teflon seal -- two different part numbers. If you want I can go hunt the invoice and get the numbers...

I need the part numbers if you have then for the o ring and seal.