live with leaking lift or repair?

Tiger Joe

Member
So i have a small dilemma.

my 8n lift works fine, but does leak down rather quickly- it takes roughly 45 minutes for my plow to go from up in the air to on the ground once I shut the tractor off.

I'm debating if I want to take the top cover off, toss in a new NAA style piston and seals, and probably a new relief valve while Im in there.

my question is- is it worth the work? Will my lift likely gain and stay up longer now?

I'm guessing the first thing I should do is pull the side cover off and watch for drips, correct?
 
I have fixed several of them. But if it takes 45 min
for the lift to leak down and find something better
to do with my time. Hint - I always lower the
implement before I get off the tractor.
 
If it takes that long to drop, then in my mind you do not have a problem. One should not parp it with the lift up anyway, think of kids and safety!
 
If you're looking for something to do, go for it. You will get plenty of help.

But....as others are saying....a 45 minute leakdown isn't a problem.
75 Tips
 
(quoted from post at 10:16:04 08/04/14) If you're looking for something to do, go for it. You will get plenty of help.

But....as others are saying....a 45 minute leakdown isn't a problem.
75 Tips

What is the "ideal" or best case hold time for an implement? I swear that I've read on here that someone left a brush hog up overnight?!?! Honestly, I would be perfectly fine with a few hours, but right now what bugs me is I can actually hear the lift dropping when Im in the garage.

honestly, my tractor fix would be a test run, i know 45 min is livable, but I always strive for perfection. My dads tractor drops after about 10 min with some serious weight on the lift, so fixing mine will be a dry run so we are "experts" by the time we tear into his.
 
Even 10 minutes is no big deal. As long as it doesn't drop just because you pushed the clutch in - like some folks have reported here - then it really doesn't matter. As others have mentioned, it is good practice to lower the implement when you get off the tractor, especially when you have shut it down. I absolutely always do because I have grandkids around and I don't want one to lower an implement onto the other if they happen to get around the tractor. If it's already on the ground, not much they can do...So, there's really no big reason for it to be able to hold an implement all night or even more than a few minutes. As long as it is working correctly when in use, that's what really matters.

But, if you want to tear into it, it's not that hard. I would order one of Zane's adjustment jigs first, though, so you can adjust the lift cover correctly while it's off the tractor.
 
" What is the "ideal" or best case hold time for an implement?"

Days.

I have 4 8N's & a 740; a disc will stay up for 2 days on one of the N's. It will drop to the ground in 30 minutes on another.

Before you start, see tip # 16 to make sure it's a top cover issue. It could be a leaky pressure relief valve.

And, before you start, it would be a wise move to get a jig from Zane Sherman to adjust the internal linkage. And, make a couple of “guide studs” by cutting the heads off of two 7/16-14 x 3 5/8” bolts. Also, if your lift cylinder rebuild kit has the leather washer, get CNH part number 87051231 which is the neoprene washer for the lift piston instead of the leather one.

The lift cover weighs nearly 100 lbs with the upper lift arms attached, & is very hard to maneuver. An engine hoist is an excellent idea. Remove the seat and spring, disconnect the upper lift arms at the knuckles. Remove the 14 bolts that hold the cover to the housing. (note that there are three different lengths) DO NOT remove the four nuts under the seat! Remove the right side inspection cover so you can remove the control rod tip from the pump intake valve. Lift the back of the cover straight up and slide a piece of wood under the cover to keep the tip of the control rod out of the rocker shaft. Once you are sure the control rod is out of the rocker shaft, you can then remove the cover. Turn the cover upside down, remove the four bolts that hold the cylinder to the cover, & use a little compressed air on the cyclinder to remove the piston. Check the cylinder for excessive scratches, hone if necessary. Install a new piston with "0" ring and backing washer in the cylinder. Install the CNH neoprene washer w/ the concave side toward the “O” ring. At this point, check the cam follower pin & the control rod. If the cam follower pin is worn replace it. Then, if you have a jig, adjust the linkage to specs. The ‘shade tree’ adjustment was to bend the control arm to compensate for normal wear in the linkage, springs & cam follower pin. If the control rod is bent, remove it & straighten it. (very carefully; they break easily!) Replace the gaskets under the cylinder and bolt it back on the cover. Put the gasket on the tractor (no sealer) and put the gude studs in place. Unless you do this every day or have eyeballs in your finger tips, get some help to guide the tip of the control arm back into the rocker shaft. (this is the point you will wish you had a engine hoist to hold the top cover while the control rod dances around the intake valve arm on the pump!) Align the cover holes up with the housing holes. Remove the guide studs. Tighten cover bolts, connect lift arms install the seat. Re-install the inspection covers with new gaskets.
CherryPicker.jpg

ZanesJig.jpg

75 Tips
 

Bruce,

the plan is to open the side cover up and take a look one evening when I have some time.

If i dont see major drips, I might throw a new valve in just because it so simple

I dont have any kids so if I leave something in the air on the back of my tractor, nobody is going to be around it anyway
 
45m or 45s

45m might just be NORMAL!

if it leaks down in under a minute.. tat's fast.

in any even.. if it leaks down too fast.. it isn't a big deal to repalce gaskets and piston and oring, cyl if needed and relief valve.. etc.
 
(quoted from post at 14:20:30 08/04/14) 45m or 45s

45m might just be NORMAL!

if it leaks down in under a minute.. tat's fast.

in any even.. if it leaks down too fast.. it isn't a big deal to repalce gaskets and piston and oring, cyl if needed and relief valve.. etc.

Pulled side cover after work. Lift up you can clearly see a steady drip of fluid dropping down from above.

I didn't run the tractor long enough for the fluid to get hot, but even cold I had about a 1-2 drops per second

Also stuck my hand down in the fluid and it's really dirty/gunky.

I'm thinking I need to get myself an naa piston and clean out my hydraulic pump.

Iirc didn't I read on here before you can flush this out with kerosene once you drain the fluid?
 
If it takes 45 minutes for the plow to drop I wouldn't worry about it.
Think about this: I don't remember the exact number off hand but your hydraulic pump puts out about 2.5 or 3 gallons per minute. Your lift cylinder holds about a pint of oil. So your pump puts out WAY more oil than needed to keep the lift operating properly even if it leaked down in 45 Seconds.
 
These are great picts. I have a simpleton question as I never pulled the lift cover off or ever had a chance to look inside one of these units and I have shied away from opening it up.

Where exactly is the delivery tube or the part that brings the oil up into the piston. I just cant picture what actually connects the pump up to the lift cover other than the control arm assembly. I have starred at the master parts catalog but it definitely ain't hitting me like a ton of bricks.
 

You see that bottom picture of Bruce's?? Almost right above the ball at the end of the draft/position control selector handle, there are 3 holes in the cover. Two are bolt holes. The one in the middle routes oil to the lift cylinder and mates to the tube shown in the photo below. Can't recall exactly how that tube is connected to the pump. But, that's how it gets from the pump to the cylinder - up that tube and into the cover where it is fed to the lift cylinder..


mvphoto9830.jpg
 
Well here is a crazy one guys.

So I came home and fished around in there. I stuck my hand down in the sump and felt the sludge and though I need to clean it out. I honestly didn't do anything except move some sludge around.

So I said ok I'm gonna my lift drop to have a exact number to tell the forum. Well I put it up and 35 min later it's still up. So I thought "maybe my stabilizer bars or a piece of dirt in the pump are somehow binding and holding it up". So I dropped it, took the bars off and reset it. It worked smoothly.

I times my stopwatch perfectly- I turned the key of the tractor off and hit start. I even set up a tape measure so I could measure the amount of drop over time. After an hour I gave up watching and left. 3 hours later I came back and it hasn't moved!

I have no idea what I did but it is working 10x better now
 
The problem I have with those "it fixed itself" repairs is that
they tend to unfix themselves almost as quickly.
And you did say you had a leak up top to boot.

If I were using a plow, I wouldn't worry about the 45 minute drop.

If I were transporting a rotary mower it might be a different story.
I wouldn't want to have to have the PTO/mower running all
the time to keep it raised. Granted, you could disconnect the
PTO shaft, but then I'd lose that while driving down the road!
There are also lift blocks for this purpose, but I don't own one.

I always lower my implements too. Why make the seals hold all
that weight/presssure for an extended time? Although, it might
help out with that goal of becoming an expert at changing them! :)
 

mramble, thanks much for the pict and explanation. It now makes sense. Kinda wonder why more folk don't complain about leaks between the rear casting and top cover. Seems like a lot of pressure passing through that gasket.
 
When I was little our N was MUCH newer. I can remember it
holding the rotary mower up off the ground for days - tail wheel
and all. By the time I was in high school it was dropping pretty
steady but it still probably took 15 minutes for hit the ground. I
honed the cylinder in mine and installed the new piston. It
stays up for an hour or so. I'm happy with that.
 
I'm looking at this very same repair in my near future and as the OP was a bit intimidated,so am I.It really helps seeing the pics of the top cover inverted like that.Trying to muster up the courage to attempt this repair.You guys make it look possible.I'm wondering though your feelings about using permatex or just the oem gasket or both.This was a helpful post .Thanks to all for sharing these helpful posts.M. M.
 
I used just the gaskets, no sealer.
I didn't want any chance of sealer traveling
in the oil and plugging other things up.
 
(quoted from post at 10:58:21 08/04/14)
Bruce,

the plan is to open the side cover up and take a look one evening when I have some time.

If i dont see major drips, I might throw a new valve in just because it so simple

I dont have any kids so if I leave something in the air on the back of my tractor, nobody is going to be around it anyway

When I was a thirteen year old kid, if you had a tractor in my neighborhood, I would have been around it one way or another.
 
45 minutes? not driving you batty with 'corrections' while running?
I'd leave it alone. The smallest snafu during the repair, and it will be worse than that....
I've had new tractors that leaked down after a few hours.
Complaining to the manufacturer does no good at all.
"some minimal leakdown is normal"
Telling them that my 70 year old tractors don't leak doesn't work either.......


(quoted from post at 10:58:21 08/04/14)
Bruce,

the plan is to open the side cover up and take a look one evening when I have some time.

If i dont see major drips, I might throw a new valve in just because it so simple

I dont have any kids so if I leave something in the air on the back of my tractor, nobody is going to be around it anyway

Up to you....but the gremlins that control machinery breakdowns will always wait for the time your foot, etc, is under it, before they do the full hydraulic failure dirty trick...
 
well like i said guys i checked it last night and after 3+ hours it was still up. Actually looked like it hadnt moved at all.

This morning when I left for work, it was on the ground. So that means it stayed up somewhere between 4-12 hours.

Is there a way to clean pump out without removing it? Like I said I felt a lot of sludge in the bottom of mine and would like to flush it out with something if possible
 
" Is there a way to clean pump out without removing it? "

Yes.

But I wouldn't do it.

There are two ways to clean the pump; the “quick clean” that gets a lot of the sludge out of it, & the right way that gets all of it, including the hard packed crud in the pump base.

For the quick clean, after you get the old fluid drained out (overnight is best) remove both inspection plates & start pulling the sludge in the pump base out by hand. Then, get a couple of gallons of kerosene or diesel fuel & pour it into the pump base. Catch it in a bucket & reuse it. (Some folks use a hand garden sprayer.) Flush the pump base out 5 or 6 times. Do not start the engine to run the kerosene through the pump; kerosene and diesel fuel do not have sufficient lubrication properties for a 60 year old hydraulic pump designed to be immersed in 90w gear oil. Some folks say it’s ok to start the engine, engage the pump for a minute or two, then turn the engine off. Your call on that one.

This 'quick-clean' is not as effective as dropping the pump & doing a full job. But if the choice is between doing nothing & the quick clean, spray it out. It worked for me for 3 years on my 1951 N. If you have the time, drop the pump; that is the right way to do it. I’ve done it both ways & don’t plan on doing the quick clean again. That’s because dropping the pump is not a big deal. If you have hard packed crud in the pump base, you are wasting your time w/ the "quick clean".

With all of the fluid drained out, block the front wheels & get the rear wheels up at least a foot. (you'll see why soon enough) Remove the 4 bolts holding the PTO shaft in & pull it to the rear & out of the tractor. Loosen all of the bolts. Remove all but 2 corner bolts. Then, carefully remove them. If you are lucky, the pump will drop free (and dump a pint or so of hydraulic fluid down your sleeves). If not, wrestle it free. The pump has 'ears' that fit into the housing; wiggle it a bit & it will drop free. If you have the rear tires a foot or more off of the ground, you will have enough arm room to hold the pump & lower it at the same time. Put it on your work bench & remove the safety valve (p/n 638) and the control arm lever (p/n 643) which will allow you to remove the intake & exhaust valves (p/n’s 640 & 698) Drop all of it in a bucket of diesel (or mineral spirits) or your parts washer & let it soak overnight. Once it has a good soaking, get it on the bench & start blowing it out w/ compressed air. Run cleaning fluid into the hydraulic discharge near the test port & make sure you get a good flow out the small hole in the side of the pump were the control valve fits. I don't see much need to pull it down any further just to clean it. But, I always replace the safety valve (p/n 638, about $25) Reinstalling the pump is harder than pulling it out because you have a gasket to worry about. (no sealer on the gasket) And, you will probably need a helper to guide the control rod into the pump rocker shaft unless you’ve done this 6 or 7 times before!

While you have the PTO shaft out, it would be a good time to replace the seal on it. It's got two spring clamps around it. Take your needle nose pliers & remove the one in the front. Then, hang the shaft & bearing housing in your vice & tap the butt end of the shaft; the bearing cap will come off (and the shaft will land on your foot). Then, remove the other spring clip from the other side of the bearing. At this point, remember that you never bought a seal driver & go get a BF socket & drive the seal out. If you have the new style seal, the white side goes out. (open side to the oil) Put some grease on it.

Contrary to conventional wisdom, not a lot of water gets in the oil from the shifter boot. Of course, if it's bad, replace it, but you get water from the draft control spring & the dipstick. But, most water is just a byproduct of the heating/cooling cycle of the oil.

You’ll need a pump gasket, safety valve, inspection plate gasket(s), PTO seal, PTO gasket, gasket sealer & 5 gallons of fluid to do all of the above.
75 Tips
 
Thanks bruce.

I knew I had seen the quick clean method before.

I know dropping the pump is probably best, but right now I've got a to-do list thats several pages long, so I may do the quick clean just for a little bit of piece of mind, as you said its better than nothing.

my hydraulic fluid is only 8-10 months old, so would it be safe to just strain it thru something and then put it back in once im done? I was thinking of using an old window screen to strain it
 
" I was thinking of using an old window screen to strain it "

I wouldn't bother. Probably the only contaminate in it is water.

Put it in a bucket & let it sit overnight & whatever water that's in it will settle to the bottom.

And.....given that your problem is most likely in the top cover.....I'd just leave the pump alone.

But that's just me.
75 Tips
 
And, before you start, it would be a wise move to get a jig from Zane Sherman to adjust the internal linkage. And, make a couple of “guide studs” by cutting the heads off of two 7/16-14 x 3 5/8” bolts. Also, if your lift cylinder rebuild kit has the leather washer, get CNH part number 87051231 which is the neoprene washer for the lift piston instead of the leather one.

ZanesJig.jpg

75 Tips
[/quote]

Bruce, is that Zane's Jig in the pic?
 
"Bruce, is that Zane's Jig in the pic?"

I'm not Bruce, but it looks like the one I bought from Zane.
You can't see the adjustment notches in the picture, but where
the control arm is against the far side Zane has cut notches into
the jig to let you know when you have it adjusted correctly for
both draft and position control. Instruction included.
 

"but I always strive for perfection"

NOW YOU ARE LOOKING TO CUT CORNERS... So what are you...
There is nuttin wrong with your hydraulics... Move on and be happy...

You could spend plenty of money and time,,, in time you will be right back were you are at even if you do every thing to spec and its squeaky clean.... BTDT.. It takes a real dufuss to thing you can somehow flush years of dirt out of the system with a spray wipe and go... It is a N thang and somehow gets you points...

If you are what you say you are look into a live hydraulic set up either convert you N are buy a tractor that came that way from the factory...
 

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