52 8n No Visible Leaks, No lift

[zacsmith99]

Evening All,
I have a 1952 Ford 8n. The lift will not work at all, even with the arms disconnected. I had a neighbor replace his recommended parts after inspection and they include, Lift piston, rubber and leather gasket, lift piston cylinder, and the pressure relief valve. With PTO engaged and the lift lever in the up position, the fluid on the inside moves very little, only enough to be from the PTO and the square pistons moving. I ensured the control arm was connected to the pump. I removed the bolt on the side of the bottom cover and drained what I assumed was a lower cylinder port. maybe half a quart came out. I cranked the tractor with this bolt out, pto and lift engaged and maybe got .5 gpm, not the rush I would expect. I replaced the bolt, topped off the fluid and cracked the top cover 1/8 of an inch and then cranked and lifted, roughly the same result, mild flow running out the high pressure line/top cover junction. with everything sealed back I grabbed the lift arms and moved them up and down fairly easily. I couldn't tell if the lift arm piston was supposed to be connected or if it just floated in the tube. I feel my next step is to rebuild the pump, Does anyone have any other suggestions or troubleshooting steps that may help pinpoint the issue?

Also worth noting the issue started in the winter. The scraper blade I was using at about 300lbs. I noticed the blade was dragging way low and couldnt lift it back up. I turned the tractor off, checked fluid, removed blade, and it started working again. Re-Attached blade, scraped and lifted as normal for another 30 minutes and then realized that the blade was low again. It hasn't lifted since.

 

[Soundguy]

WOW..


parts replacement should never have started without diagnostics.

first, lets clear up a few things.

that lower 'bolt' is the test port on the base plate of the pump.

cracking the top cover means you have ruined the gasket.. it needs to be replaced.

if the cyl was replaced under the top cover, you HAVE to use all 3 gaskets under it that it needs.. 2 small ones the size of a penny, and one oblong one a few inches wide, but narrow.

with the top cover off, you should also have replaced the cam follower pin.. with extreme use, it could be completely sheared off, meaning in position mode.. you would have no lift.

Next, you always have to make sure that arm from the top cover linkage to the rocker in the pump moves the control valve fully in and out as you move the 3pt handle.

pump volume is 2.85gpm at max... seeing .5gpm at lower rpm is normal.

as you saw when the hyd cyl was replaced, the piston free floats in the cyl bore. a dogbone connector rides the cup in the back of the piston.. this dogbone is pinned to the rockshaft, which rotates the upper lift arms.

thus you can pick the upper lift arms up freely with no connection to the piston in the cyl bore.

pull the inspection cover.. look for control valve movement full in and out.

look for oil leaks from the top cover running inside the casting where the standpipe take oil up.

 

[Soundguy]

ps.. this would be a great post for the vintage ford section.

the hyds on this machine are quite alien in comparison to regular, modern tractor hyds...

 

[zacsmith99]

Soundguy, I do not see leaks anywhere within the housing and i can confirm full range of motion on the control valve. I will inspect the top cover again tomorrow and see if I can see that the cam follower pin and its condition. The worry I have is that the fluid that came out the first time I drained it, was thick, snotty, mudlike goop that I think may have clogged the pump, it there a good way to test pressure? The .5 gpm was with the tractor in neutral at full rpm, I don't know if that would be considered max or not.

Also worth adding, I cracked the top cover because I could already tell the gasket would need to be replaced, it was not centered well and was showing out one side a hair, I will be replacing the gasket for sure!

 

[zacsmith99]

I looked at some of the pictures I took the other night, I can confirm the cam followed pin is in good condition.

 

[bamboozled]

I rebuilt the pump in a 2N earlier this year with similar symptoms. Older guy, bought it and it worked fine initially. Sat all winter and the 3PT wouldn't lift.

We drained the fluid so we could see if the 3pt lever arms were actuating the control valve, they were trying to but the valve wouldn't move. The control valve was frozen in its bore due to varnish and old oil. We dropped the pump and I soaked, cleaned and rebuilt the pump. Once back together it worked like a charm. I actually tested it by spinning the PTO by hand and it built up enough pressure to raise the 3PT arms.

I am aware the 2N and 8N pumps are slightly different in actuation. But troubleshooting is the same. You need to drain enough fluid out of the tractor to be able to see what is going on. And if you are talking about old fluid I'm sure it needs changed and the pump probably needs dropped out and rebuilt and the belly of that thing cleaned out of all the old sludge.

 

[zacsmith99]

When you say rebuilt, do you mean pistons, side ckvers and all or just gaskets or what? Because there are multitudes of kits out there for these.

 

[Soundguy]

Pressure test by chaining upper lift arms to axle trumpets, then lift 3pt control. You will need a gauge with an orb adapter on it to screw into the test port... It is not pipe thread.

 

[zacsmith99]

Awesome! I'll have to find a gauge but that shouldn't be too rough. Thank you

 

[zacsmith99]

ok, so, apparently no shops in my 2 surrounding cities had pressure gauges that would fit a threaded end like that. I have resorted to removing to pump. There were paint chips, sludge, metal bits and all kids of small trash in the cylinders. What I am having issues with now is understanding how the pump actually works. I see that the high pressure line goes through the lower cover, into a metal tube and then into the top cover, but i don't understand the high pressure flow within the actual pump or even where the intake is. If anyone has diagram to this or could help explain, it would be much appreciated so that i can better assess where my potential problem areas will be. I am going to rebuild it all once i get parts, excluding the side covers being that they appear to be in pristine shape! given the age and the milling marks, it does appear to be that old. Also worth noting, the guy that previously worked on it tightened the **** out of every bolt including the drain plug which is now shattered and will be replaced... I swear, if it weren't for bad luck id have no luck at all.