8N Hydraulics

Jim in Western MI · Aug 25, 2015

My 48 8N is becoming a bit weak in the lift. It works fine when warm, but in cold weather it may take several minutes before it will lift an implement, then sometimes it may lower it without moving the touch control lever. In really hot weather when used for more than a couple of hours, it will go to bobbing. Otherwise, it obeys the touch control very well and responds to even minimal movement. As far as I know, the system has never had more than changing the hydraulic fluid every five years or so, at least since I had it; though the relief valve was replaced but that didn't change anything. I'm aware of the o-ring modification kit, but a local mechanic says he has never used anything but the original type. Is this something best left alone and work around its slightly annoying habits and risk a rebuild not working so well with the touch control, or would I expect it to work even better..., and is the 0-ring type superior? Thanks for any comments.

souNdguy · Aug 25, 2015

what do you have in it now? gear oil?

as for the oring vs steel ring.. you need to see if it has a significant leak out of the cyl mouth. if so, many of us lightly hone the cyl and then install a naa piston and oring/backup washer. I fhte cyl is heavilly scratched, you will have to replace, and perhaps hand fit the new cyl a bit.

slow lift that gets better warm is usually oil.

good lift that gets worse hot can also be oil.

you may have a realy cheap oil with very bad viscosity range in it.

add a small leak from wear, and you have thick cold oil, managable warmn, and hunting due to a leak when thin and hot.

Jim in Western MI · Aug 25, 2015

I have always used the 134D fluid from the Ford (New Holland) tractor dealer.

souNdguy · Aug 25, 2015

wow.. the spendy stuff.

if you have that much disposable income.. I'd get a different tractor..

check for leaks.

lift a load and look thru the inspection port at the cyl mouth.

Jim in Western MI · Aug 25, 2015

I try to take care of this one (!) so I won't have to buy another one......

TheOldHokie · Aug 25, 2015

(quoted from post at 11:20:13 08/25/15) My 48 8N is becoming a bit weak in the lift. It works fine when warm, but in cold weather it may take several minutes before it will lift an implement, then sometimes it may lower it without moving the touch control lever. In really hot weather when used for more than a couple of hours, it will go to bobbing. Otherwise, it obeys the touch control very well and responds to even minimal movement. As far as I know, the system has never had more than changing the hydraulic fluid every five years or so, at least since I had it; though the relief valve was replaced but that didn't change anything. I'm aware of the o-ring modification kit, but a local mechanic says he has never used anything but the original type. Is this something best left alone and work around its slightly annoying habits and risk a rebuild not working so well with the touch control, or would I expect it to work even better..., and is the 0-ring type superior? Thanks for any comments.

Based on the symptoms I would guess a small leak in the lift circuit. You didn't mention it but I would also guess it leaks down with the PTO shut off.

As for o-rings versus steel rings an o-ring is a superior hydraulic cylinder seal. But if and when I ever have to make that change it will be with a new cylinder as well. O-rings don't like rough or scored cylinder walls....

TOH

Bruce (VA) · Aug 25, 2015

" I try to take care of this one (!) so I won't have to buy another one...... :"

Amen!

You can find the source of the leak as soundguy suggested (and as described in tip # 16). Then, assuming it's the piston/cylinder, post back for info on replacing it all. With the o-ring.

Ever had the pump out for a good cleaning?

You can drop & clean the pump as well as rebuild the top cover & never have another lift problem. Probably 6-8 hours total time if you're a jack-leg mechanic like me. Nice winter project.
75 Tips

Jim in Western MI · Aug 25, 2015

I'm about a 9/10ths of a jack-leg mechanic..., I've pulled heads and had valves and seats ground (by a shop) and reinstalled it with nominal results, I'll take on about anything electrical (wired one office building and three houses) or plumbing (one house and all repairs to mine); but I've never fiddled with hydraulics and the stories on this forum about the heavy lift covers, pumps, getting connecting rods lined up, and having trouble with the touch control not controlling well after rebuilds have spooked me from taking this on. I have a good place to work on things with a concrete floor, good lights, and good insulation..., so there is that possibility. I generally consider experience to be the best teacher tenfold, and having none with this, I may take it two hours to Hobo if he'll work on it. He could probably do this with his eyes closed!

souNdguy · Aug 25, 2015

Yes, Hobo is a pro mechanic, he as well as others here could do it eyes closed.

If you understand plumbing, you have a leg up on someone with no hydraulic experience.

For easier N hyds, most of it comes down to condition of the old parts, how close to spec any new parts you get are, and proper assembly.

the lift cover, for sure, is SOME weight, but if you can lift a big feed bag, you can lift it off.

sometimes the gasket sticks it.. if so, put a bottle jack on the ground and a piece of wood from jack to under the lift arm housing, and give it a couple pumps ( once you recheck the bolts out ) with some stress on the lift cover and glued gasket, ) them tap arund the gasket and cover with a deadblow hammer or large rubber body mallet. usually pops right off.

In the end, if you take it to Hobo, it WILL get done correctly.

Bruce (VA) · Aug 25, 2015

If you can do all that, you can pull the pump & the lift cover w/o any problems. And, chances are 9 out of 10 that you can rebuild both. But, as soundguy said, you can take both to Hobo & be 100% sure they will be done correctly.
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8N Hydraulics

Jim in Western MI

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Jim in Western MI

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