New (old) 641- no 3 pt hydraulics - prime problems?

motzingg

New User
Howdy,

New to the forum and somewhat new to old tractors, I grew up around some of this stuff, and I work on everything from old motorcycles to old cars, but this is my first antique tractor of my very own.

I picked up a somewhat neglected 641 a few weeks ago. It had sat in a garage for the better part of the last 10 years, ethanol had rotted the carb, but i got the carb rebuilt, ignition system tuned up and it runs pretty good. Someone went through it maybe 30-40 years ago and cobbled together the loader, power steering, and did a bunch of creative but hacky 'upgrades' then since then i think it has been used when it would run and neglected when it wouldn't. Trans, hydraulics were both full of milkshake.
mvphoto23294.jpg

only problem is- when i bought it, there was very little (normal) oil under it from sitting. When i got it started up it blew a gallon or more of oil out of the hydraulic manifold where it bolts to the bottom of the transmission housing.

This was the problem:
mvphoto23295.jpg

I was able to get a pretty good weld on it and it is bolted back on and no leaks. Obviously it was out of tractor juice so i filled it back up with some 'universal hy tran' from Fleet Farm. I shook the 3 buckets and this was the thickest, feels like about 30-40 wt (oil or 80w gear lube). Listed as being for 'ford' but no EP additive so i put 80-90 in the trans and diff.

mvphoto23296.jpg

Anyhow filled it up, no leaks, everything looks good, figured 'here we go' and.... nothing. Not even a hint of raising. So i pulled the plug and bled the system, lots of air coming out, lots of oil flow, but still nothing. There is lots of flow, there is intermittent air coming out, making a sputtery mess. It doesn't look like another youtube video where the guy pulls the plug, waits a few seconts and it runs clear, this thing is just shooting out foamy spluttery oil, but lots of it.

I have to think that even given the miniscule pressure coming out, just by flow alone, i could get some motion on the 3 point cylinder. Even when i lift the arms up the piston wont take up the slack. The first 10 years of my engineering career was spent on hydraulics and this just doesn't look like an air-in-the-system type problem unless there is some kind of piloted valve that wont build pressure to open, and i just don't understand what is happening in the valve/lift mechanism that well yet.


I'm not *scared* per se to pull the 3 point valve/ram cover, its just a good couple hours of work, and i'm not sure if its necessary. I saw the video on youtube with Rachel showing how to bleed with compressed air in the transmission.... that is pretty low impact, once i get my air compressor up and running (just moved 3 weeks ago to the new place) i will certainly try that.

so a few things to ponder:
1) Are these things really that bad to bleed, do i need to get radical and do something like fit a hose from the pump to drain the bleed port into the reservoir and just let it run for a half hour? Its a relatively simple task just takes some doin'.

2) what would have caused it to break the manifold? since it didn't have oil underneath it, it obviously broke on the pressure side and possibly either from freezing water (there was lots of water in the system) or from over pressure (relief valve stuck?) if it broke from water it just so happens to have sat for years not leaking a drop, then when i fired it up, came apart and started gushing? i dunno crazier things have happened but it seems like a long shot


i dunno, where would you folks start looking? do a more thorough system bleed ? Pull the valve body? I read through a bunch of threads on this and i didn't see anyone having this exact issue, is there something dumb that im' overlooking? I'm not opposed to getting greasy but i like to trouble shoot these kind of things in an orderly fashion and would rather not tear up a bunch of stuff for no reason.
 
lots of air coming out, lots of oil flow,

Welcome to the forum - Glad to have you!!

Bleed the system by running a hose from the bleed plug to the fill plug under the seat and run it till there is no air. If bubbles never stop you likely need a pump seal and maybe a shaft. Although the pump seals are a source of suction air leaks, don't forget the manifold between pump and tractor transmission as well as the tube running through the case into the hydraulic sump. They have been known to rust out & O-rings will break down.

Good luck!!

Also, if you can turn the front wheels around, the wheel bearings will be most grateful :)
 
don't forget the manifold between pump and tractor transmission as well as the tube running through the case into the hydraulic sump. They have been known to rust out & O-rings will break down.

as you can see from the pics, i had to weld up the manifold so i replaced all the o-rings on it. I didn't have the 'right' ones but i picked some out of a generic o-ring assortment kit i have and i'm pretty confident that they are close enough to be making a good seal.

the tube inside the case is what i'm scared of, with as much water was in this thing, and for who knows how long, who knows what it looks like in there. there was pure water condensation droplets on the inside of the fill plug when i opened it up.


good to know about the pump seals, anything like a lip seal or a packing that would dry out from 10 years of sitting is high on my list for a potential culprit due to the the fact this sat around so long. I'd like to get it working before changing variables but i'm sure a hydraulic pump rebuild wouldn't be a terribly bad idea. Only 600 hours on this tractor so your 'wear' type failure modes are probably less likely... i'm looking for 'sitting around' and 'neglect' type failures.

I'll plumb up the hose this weekend and see how it goes.
 
I've never known one to successfully "weld" the aluminum hydraulic manifold.

That said, the OEM O rings for the hydraulic manifold are square cut. They will seal properly and not squeeze out sometimes causing the manifold ears to crack upon tightening, a common result of using improper O rings.

If the O rings do not seal properly, the pressure line will leak oil and the suction line will suck air resulting in loss of prime.

How much water did you find in the transmission, differential and hydraulic sumps?

There are steel hydraulic tubes in the transmission that will rust when there is water in the transmission oil, resulting in perforation. Moreover, significant amounts of separated water in the hydraulic sump will find its way into the hydraulic lines in the transmission and will freeze in cold climates causing the lines to burst.

Any of these three issues, or a combination thereof, could be causing your problem.

Dean
 

Dean, thanks for the info.

As far as welding (or 'weld' ing as you put it, haha) I taught myself to weld cast aluminum 10 or so years ago when a lot of professional welders told me it couldn't be done. I've welded up tons of stuff to date including some tricky manifold flanges like this. I've got to get it to build pressure to see if it works or not, but i'm pretty sure it will be fine. The o-rings i put in there fit, it would be leaking one way or another by now if there was a leak, and there isn't. Even if the suction side had a leak, the tractor has been sitting for 2-3 weeks now with it full of oil and no external leakage.

So i had a few more hours to mess with this yesterday. I put a nipple and clear vinyl hose coming from the bleed port on the pump and dumping back into the fill. It was mostly pumping air, tons of air. There was good flow and its not just churning, there is actual fluid movement, so i don't think its a problem with leaky check valves. I thought maybe i had somehow messed up the level and my dipstick is missing, so i poured in a bunch more oil, so much it actually started coming out the dipstick hole. This helped, now i was getting less air, but still getting air. It was flowing pretty steady and good flow, so i put the plug back in but still no movement of the 3 pt.

Also the pump is not making the characteristic whine you would expect to hear from it running under load so i'm pretty sure its not building pressure. I'm proabably going to rig up a test gauge to that port somehow.

So it is almost certainly picking up air. I thought the suction tube would be totally submerged in the transmission so even if it was rusted out this wouldn't be possible, but perhaps it is? There doesn't seem to be communication between the trans and hydraulics, they seem to be maintaining their levels.


I'm not sure where to go next. I know this much:

Air is getting in the system, probably from somewhere low enough that by massively overfilling the reservoir it goes away

even though air is getting in, it still doesn't work when the overfill causes it to pump clean.

so i've got either one problem causing both or two problems (or more) resulting in these symptoms. I'm feeling pretty confident that the pump isn't the problem, unless it would be the shaft seal on the pump pulling in air? Engine oil isn't going up either so that seems unlikely.

i think my next step is going to be order the 3pt control plate gasket set and crack it open, that will at least tell me what is going on in there.


As far as water in the hydraulics, i'm not sure, it was all very emulsified milkshake goop, when i look in the fill hole, nothing appears to be visibly rusted inside the case.
 

You may need to bleed the pump. Two types of the pumps were used, vane and piston. The vane type will have a flow control knob on it.
My 59 has the piston type and this is how to bleed it.
There is a pipe plug with a hex socket on top of the pump at the front. Loosen it enough so it will turn easily. Start the tractor and loosen it a little more with the hex key until you can see bubbles coming out of the threads. When the bubbles stop and you just get oil, tighten the plug and move on to whatever your next step is.
 


Dollar Bill, thanks, being as that is the easiest thing to do, i will do it first.

Ratcobob- i hooked up a section of clear vinyl tube back to the fill plug from the bleed port (so i could see the bubbles) and ran it for a half hour, it never 'bled out' because air is being sucked into the system somewhere.
 

My tractor had sat out for years and the water accumulating in the transmission had rusted out the pressure line and the resulting leaks overfilled the transmission.
Both lines are available -
http://www.link_disallowed/acatalog/copy_of_copy_of_jubilee_naa_hydraulic_pump_lines-1.html
You will need to drop the engine oil pan in order to have clearance to pull the lines out the front if that becomes necessary.
 
Hey all, its been awhile since i checked in.... this problem is still vexing me.

The tractor made it through the winter as my only plow vehicle to move the 90+ inches of snow that we got hit with this season, breaking all records... 40+inches came in Feb alone and the little ford got it all cleared (albeit slowly)

This summer has been busy with farm stuff and a million other projects, but i've worked on the 3 points off-and-on.

I removed the hydraulic pump and spent about 3 months trying to get that fixed. The nose housing was cracked- A Ha ! I thought here is my problem.... after trying to weld it a couple different ways, i finally bit the bullet and bought the repop casting for 180 bucks, over 250 by the time it was all back together with new bearings and seals.

Got it on and nothing. Now i have fluid pressure to the test port in front of the seat when the control valve is in the down position, but still nothing i can do will make the 3 point raise up.


Next on the agenda is tearing off the whole top cover and seeing whats going on in there, unless anyone has any other suggestions of something else i can check?
 


hmm pics not behaving... don't have a 'after' picture but i should take one for posterity

here is my failed attempt at brazing, when things heated up i found out the other side was cracked too... darn

mvphoto41368.jpg
 

oh yeah- so- back to the original problem, some more clues that might help someone smarter than me figure this out

so clue number 1- when i bought the tractor the 3 point was 'up', the back blade was on the ground but it was holding the arms in the up position, in the process of trying to get it to raise, i only succeded in dropping the arms

2- the manifold and pump were obviously freeze-cracked (well, not obviously but there was a ton of water in the oil so thats my guess)

3- the pump is making some better sounds than it was before (whining fluid circulating sounds) but nothing i can do will make it load down so it seems like something with a relief valve dumping to tank or something like that

4) there is very little resistance on the up/down lever (right side of the tractor with the cage around it) i'm not sure if there should be- definitely doesn't feel like any kind of detent or anything.


feels to me like a valve is stuck but where and what valve? any other thoughts?

thanks again for any help, suggestions, comments, crackpot theories
 

Did you know that on Classic View your recent posts show up as FOUR seperate, completely disjointed posts that are not connected to ANY part of your original post?
And did you know that the majority of people here read this board in Classic view?
And they sure aren't willing to sleuth out this YEAR OLD POST to try to help you?
For your own sake, if your original post is more than about TWO DAYS OLD start a new thread. That way Every one will see it.
Or better yet, quit using that bloody Modern View and use Classic.
 
(quoted from post at 08:39:21 08/20/19)
Did you know that on Classic View your recent posts show up as FOUR seperate, completely disjointed posts that are not connected to ANY part of your original post?
And did you know that the majority of people here read this board in Classic view?
And they sure aren't willing to sleuth out this YEAR OLD POST to try to help you?
For your own sake, if your original post is more than about TWO DAYS OLD start a new thread. That way Every one will see it.
Or better yet, quit using that bloody Modern View and use Classic.

I use the Modern view with little problem. with this post I switched to classic and your post does not even show up nor does the last photos. I never have understood why they still use both classic and modern.
 

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