2N Ford - hydraulic lift issues

Farmer MM

Member
I "think" I blew out my relief valve! I had replaced it a few years back, and the other day I backed up against a larger dirt pile a little too hard, and after hitting it, the lift lost its lifting power once warmed up. Cold it lifts fine. I plan to drop the pump this time to replace valve, as putting it in from the side inspection hole was not fun. Am I suspecting the right area?
 
Farmer MM.........I doubt you blew yer pressure relief valve, that is what it is for. And yes ittza SOB to replace thru that 6-in round hole. I would suspect you blew yer hydraulic piston, which mean yer gonna haffta take the top OFF. Ittza all day job. Remember, yer dealing with 5-gals of hydro-tranny oil so you wanna try to do it without draining the oil. BIG tip: swipe yer gasket with warm water to relax the gasket and you won't haffta fight gittin the bolts inna their holes. I'm gonna guess yer familar with wrenchin'........the amazed Dell
 
Before you do anything, remove the right inspection plate and try to see where the leak is occurring. If it is coming from the top, you can
remove the topcover without draining the oil. Just remember to disconnect the control linage from the control valve.
 
(quoted from post at 05:36:49 10/18/16) Before you do anything, remove the right inspection plate and try to see where the leak is occurring. If it is coming from the top, you can
remove the topcover without draining the oil. Just remember to disconnect the control linage from the control valve.


Thanks all! Tonight I'm going to test the hydro-pressure. Next, I'm pulling the inspection cover. Will let you know results.
 
I concur with the others. You need to perform some basic root cause problem solving methods first before spending money on parts and eschew all the guesswork. Begin by connecting your back blade, rear scoop, or other implement to the 3-point. Start tractor; engage PTO; raise the implement all the way to the top of the lift stroke with the quadrant lever and leave it there; shut down engine. The lift should hold the implement up for weeks if all is in good working order. If the implement drops to the ground in minutes, hours, or even a day or two, you have a cylinder/piston issue. Next, remove one or both inspection covers; repeat lift procedure ending with shutting down the engine; with your mini-mag flashlight, look up inside to the bottom of the top cover where the cylinder and piston are. Watch close to see if there is any signs of hydraulic oil oozing out. If so, your piston and/or cylinder need replacing. The safety relief valve is not that hard to replace. You?ll need an 11/16? stub length open end wrench or an equivalent facsimile. Some guys take an old standard wrench with not too much sentimental value attached and cut it off about 6? long. You need the short stroke to clear the inside wall of the center housing when loosening and tightening the valve. I?d start with this first then work downstream as each step either confirms or eliminates the problem.

Tim *PloughNman* Daley(MI)
 
No need to "test" the hydraulic pressure. You should already know the pressure is low because the lifting power is low.

I bend an 11/16" box end wrench at about a 65% angle mid ways and use it to reach under the PTO to remove and replace the pressure relief valve.

Had the same wrench for over 50 years just for that procedure.

Put something heavy on the lift and with the right side inspection plate off try to lift it and observer where the oil is coming from that may be
leaking down from above.

Zane
 
(quoted from post at 13:54:01 10/19/16) No need to "test" the hydraulic pressure. You should already know the pressure is low because the lifting power is low.

I bend an 11/16" box end wrench at about a 65% angle mid ways and use it to reach under the PTO to remove and replace the pressure relief valve.

Had the same wrench for over 50 years just for that procedure.

Put something heavy on the lift and with the right side inspection plate off try to lift it and observer where the oil is coming from that may be
leaking down from above.

Again, thanks ALL! This weekend's project! It quickly lifts to the maximum height, and will hold it for several days, but sloooooowwwwwly comes down. If unit is warm/hot, it takes a loooooonnnnng time to raise the blade.

Zane
 

Hello!

Took side inspection cover off, ran tractor to get fluid warm, then put 100+lb weight on drawbar. It lifted it quickly, and would hold it. VERY slowly (not immediately noticeable) it would come down. Fluid had a milky/aerated stream coming up between right side of hyd-pump and the shift-yoke arms. After shut tractor off, lots of the milky stuff came up on right side. NOTHING ever came out of overhead ram/cylinder. Am I correct...safety valve is toast?
 
(quoted from post at 20:41:45 10/26/16)
Hello!

Took side inspection cover off, ran tractor to get fluid warm, then put 100+lb weight on drawbar. It lifted it quickly, and would hold it. VERY slowly (not immediately noticeable) it would come down. Fluid had a milky/aerated stream coming up between right side of hyd-pump and the shift-yoke arms. After shut tractor off, lots of the milky stuff came up on right side. NOTHING ever came out of overhead ram/cylinder. Am I correct...safety valve is toast?
f it holds a load up for several days, then, no, it is not a safety valve problem.
 
(quoted from post at 17:50:54 10/26/16)
(quoted from post at 20:41:45 10/26/16)
Hello!

Took side inspection cover off, ran tractor to get fluid warm, then put 100+lb weight on drawbar. It lifted it quickly, and would hold it. VERY slowly (not immediately noticeable) it would come down. Fluid had a milky/aerated stream coming up between right side of hyd-pump and the shift-yoke arms. After shut tractor off, lots of the milky stuff came up on right side. NOTHING ever came out of overhead ram/cylinder. Am I correct...safety valve is toast?
f it holds a load up for several days, then, no, it is not a safety valve problem.

Hello,

It'll start dropping right away, but fully be down in 48 hours.
 
(quoted from post at 20:52:30 10/26/16)
(quoted from post at 17:50:54 10/26/16)
(quoted from post at 20:41:45 10/26/16)
Hello!

Took side inspection cover off, ran tractor to get fluid warm, then put 100+lb weight on drawbar. It lifted it quickly, and would hold it. VERY slowly (not immediately noticeable) it would come down. Fluid had a milky/aerated stream coming up between right side of hyd-pump and the shift-yoke arms. After shut tractor off, lots of the milky stuff came up on right side. NOTHING ever came out of overhead ram/cylinder. Am I correct...safety valve is toast?
f it holds a load up for several days, then, no, it is not a safety valve problem.

Hello,

It'll start dropping right away, but fully be down in 48 hours.
y answer is still the same.
 
(quoted from post at 20:34:02 10/17/16) Farmer MM.........I doubt you blew yer pressure relief valve, that is what it is for. And yes ittza SOB to replace thru that 6-in round hole. I would suspect you blew yer hydraulic piston, which mean yer gonna haffta take the top OFF. Ittza all day job. Remember, yer dealing with 5-gals of hydro-tranny oil so you wanna try to do it without draining the oil. BIG tip: swipe yer gasket with warm water to relax the gasket and you won't haffta fight gittin the bolts inna their holes. I'm gonna guess yer familar with wrenchin'........the amazed Dell

About replacing that relief valve...I had my top cover off and the fluid drained. I was sure that the trouble was in my top cover and that the pump was good. Not finding a set of stubby wrenches anywhere local, I ordered a set from Amazon prime.

I also had the PTO shaft out because I had a new 1 3/8" shaft assembly ready to put in, I had a new relief valve too. While waiting for that stubby set of wrenches to get here, I attempted to remove that control valve.

I found that with the PTO shaft removed, I was able to use the box end of a regular length open end/box end wrench through the right side inspection hole to remove the relief valve and put the new one in. It fit just right to do the job.

I don't know how much trouble it is to replace that valve with the PTO shaft in there but I know it's a piece of cake once you remove the PTO shaft. No special wrench needed.
 

All, I dropped the h-pump out, and don't see anything obvious. I unscrewed relief valve, and spring seems very weak. If valve is bad, what should be noticed? How about the dog-eared valve (hooks to arms), can that be bad? No oil is dripping from the top-ram/cover area. MINIMAL sludge around pump area.

MM
 
(quoted from post at 18:31:19 11/01/16)
All, I dropped the h-pump out, and don't see anything obvious. I unscrewed relief valve, and spring seems very weak. If valve is bad, what should be noticed? How about the dog-eared valve (hooks to arms), can that be bad? No oil is dripping from the top-ram/cover area. MINIMAL sludge around pump area.

MM

If you've got the pump out, I wouldn't think twice about replacing the relief valve. After all, how many times are you going to have access to it? I ordered a new relief valve and a new upgrade NAA piston and seals before I even had my top cover off.

There are certain things you only want to have to do maybe once during you or your tractors lifetime.

I know for darn sure I don't want to have to pull that top cover again. Even with two guys helping me it was a PIA.
 

All, The spring on the relief valve is VERY soft, and barely pushes the seat forward. Could that be where my leak is coming from? The side valve gaskets appear good. Should I tear in to the pump, and inspect parts? Where else could the leak be coming from?
 
(quoted from post at 18:32:35 11/02/16)
All, The spring on the relief valve is VERY soft, and barely pushes the seat forward. Could that be where my leak is coming from? The side valve gaskets appear good. Should I tear in to the pump, and inspect parts? Where else could the leak be coming from?
'll put a dollar to a doughnut that you are feeling of the check valve spring.
 

All, I think I discovered part of my issue. I was cleaning the pump, and the left side valve-body has a crack half way down on one of the "tube chambers"! The crack does not go through the body, only on outside. I'm "assuming" that's where some of my pressure loss is once unit gets warm. Options: braze it, JB weld it, replace it. Besides buying a new one, anybody try the other options?
 
Farmer.........JB weld don't like oil. BRAZE IT!!!.......Braze works on castiron, be certain to FLUX the braze and then cleaner-up. .........the amazed Dell
 
(quoted from post at 18:45:19 11/04/16)
All, I think I discovered part of my issue. I was cleaning the pump, and the left side valve-body has a crack half way down on one of the "tube chambers"! The crack does not go through the body, only on outside. I'm "assuming" that's where some of my pressure loss is once unit gets warm. Options: braze it, JB weld it, replace it. Besides buying a new one, anybody try the other options?

Spend $75 and replace it with a new one..

TOH

PS> Once again the evil relieve valve is exonerated :evil:
 

All, valve crack ran all the way down the chamber side, in to the inside valve area. I bought a new chamber, and hope to install next week. I suspect this has been the problem all along, since lift works fine when cold, then loses liftability once warm.

Thanks all!
 
OT: OT:
Hay Dell,

Christmas EVE is a comming. I sat on Santa's knee and said" I am wishi'N fer the $$ to buy some "DOPE".

Really, I have just finished the "stick and paper" model of a LOCKHEED early freighter. Stretched the paper and all!

Now a 50/50 cote of dope is all she needs.

Since the fresh fruit is over all I have is SS. and a cheap project. So, Christmas eve, coating the Lockheed with that sweet smell of butyrate and of cousre, CELCIC WOMEN.

How 'bout YOU?" Some cheap sleeping aid "Scotch", and another HEATH kit?

Santa.

John,PA Fidle player on the keyboard?

Take Care, "N" Friend
Official Christmas Party, Socially
 

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