My Tractor Forum banner

1 - 16 of 16 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter #1
Hi all,

I'm new to this great forum. I have a 1957 Ford model 640 that had been sitting idle in the woods for about 2 years probably. My neighbor gave up on it after it didn't run right for him and just gave it to me. I towed it into my shop and got it running again this winter but the hydraulics wouldn't lift @ all.

The good news is that so far it has survived the neglect pretty well: the previous owner replaced fluids regularly and there don't seem to be bits out of place or broken or outstanding water or rust issues when I take things apart.

My "restoration" technique so far has been to basically take things apart until I really get a good look at them and figure out if they're servicable or not. This worked fine for the engine which is simple compared to the hydraulics IMO.

I have the FO-20 manual as well as the owner's manual but I still have to take things apart to understand them because the manuals are a bit short on words if you've never owned a tractor before and don't know where some of the relevant parts are or how they work.

This tractor is equipped with an aftermarket single-lever valve on top of the hydro cover that controlled a single piston top-link arm if I'm using terms correctly. This arm did not move nor did the main lifting arms when I tried either lever with the engine running.

I tried to do what the manual said and prime the hydraulic pump by opening up the plug on the right side of the hydraulic sump with engine running and fluid came out but I don't have a pressure gauge (looking back on it now I think it was just pouring out due to gravity). Then I put compressed air in thru the dipstick hole but no dice. I drained the fluid and replaced it with traveller universal hydraulic/transmission fluid from TSC but no change. It is not leaking anything from the transmission case either so I don't think I have a busted seal or pipe in that passage but I dunno.

In the end I have just taken the top and bottom covers off of the hydraulic sump to make sure there was no clog or something and to better understand how this stuff works. The valves on the main lift arm piston assembly seem to operate smoothly. There was lots of nasty black sludge in the bottom of the sump but no water when I drained the fluid. I have cleaned as much of the black sludge up as I can.

At this point I have gotten new o-rings and gaskets for everything on the covers and the aftermarket lifting valve and am going to put it all back together and refill with fluid. I'm hoping this will restore any potential leaks to being sealed.

At long last (sorry for the long long post!!) I have a few questions:
1) I have seen mention here of verifying the pump is working and bleeding air from it. How can I do this, I don't remember seeing it in the FO-20 manual?
Just pull the plug on the side of it and redirect the fluid into the sump until air is gone?
2) In general how should I bleed the system now that I've taken it all apart after I fill the sump with fluid?
3) how do I verify a stuck/unstuck unloading valve on the lift arm piston assembly before I button up the top cover? If I am reading diagrams correctly is the little valve next to the main control valve?
4) should I preemptively get a pump rebuild kit with new gaskets and orings?
5) there are two vertical pipes in the hydro sump that the parts manual labels as "inlet" and "exhaust" for hydraulic system. Is the rearward pipe supposed to be closed @ the bottom? It is just for holding some amount of fluid or something?
6) anything alse I'm missing or really screwing up?

Again, sorry for the long post, wanted to give some history so my line of questioning made more sense.


Thanks!
Ian
 

·
Registered
Joined
·
1,864 Posts
No.. the tubes just aren't for holding fluid.

back at your right heel is wher ethe hyd lines enter the center section and go thru the relief valve ( pressure side anyway ), and then up to the cover.

I'd pull the plug on top of the pump ( piston pump ) to bleed it.

if this did not have the aftermarket valve, and instead had the blank cover, you could pull the plug and bleed it there as well.

there is also an inverted alan plug , test plug, down there by the relief valve.. you can open that and see if you are getting oil.

bottom line.. the hyd remote gets oil before the unloading valve in the 3pt.. the remote should work, if the pump i pumping and holding pressure, and the relief valve is good, and the high pressure tubes in the center housing are good... IE.. the remote should work even if the 3pt doesn't work.

unscrew the ends of the hoses at the remote valves and aim into a bucket, and operate the valve as if lifting, and then start engine.. should get oil out of one of the hoses pretty soon if it is burped and pump is pumping..

soundguy
 

·
Registered
Joined
·
6 Posts
Discussion Starter #3
thanks souNdguy! it seems that the inverted allen plug is basically the same passage as the plug on the side of the case right? or is one the supply and one a return path?

I removed that inverted allen plug to look up the tube and it was clear. I think I'll gasket and bolt up all of the covers, refill and go back to the pump side.

Before I took everything apart I tried the suggestion you made about operating the remote valve with the hoses into a bucket and some fluid came out but not quickly and it was pretty black and gross, not much amber color in it. I replaced the hoses already and squeezed all I could out of the hydraulic arm.

I guess the fact that something came out when I moved the lever could be due to some slight pressure in the system (or gravity :) ) I will focus on the pump and see if it can give pressure fluid flow thru it. Maybe sitting so long it needs an extended burping.

Thanks for your advice!
 

·
Registered
Joined
·
1,864 Posts
I doubt there was any 'gravity' flow from the remotes that are perched at the very highest part of the hyd system.

All the ports I mentioned are in the pressurized part of the circuit.. from the pump to the relief valve to the lift cover.

the oil volume in the pump itself is minscule.. extended burping is not / should not be needed.

if the oil you got out was gunky.. I'd suspect a suction side obstruction.. or gunked up pump.

find flow.. then worry about pressure.

I think I'd look at the manifold feeding the pump..

soundguy
 

·
Registered
Joined
·
6 Posts
Discussion Starter #5
good advice, I appreciate you taking the time to step it through with me. I'll dig some more this weekend.:thanku:
 

·
Registered
Joined
·
1,864 Posts
I'm hoping when you pull the pump something obvious jumps out at you.. like a wad of gunk inthe intake.. etc.. then you can get her cleaned and see what she will do... deffinately get any debri out and clean the pump..as you don't want the debri getting to the unload valve...

soundguy
 

·
Registered
Joined
·
6 Posts
Discussion Starter #7
just an update - I ordered some hydraulic pump rebuild gaskets/parts in a kit last week so this weekend I took the pump off. Nothing obvious came out that would indicate blockage but I haven't split the the pump completely apart yet. All of the bearings in the pump shaft and wobble plate operate smoothly and look fine.
The parts should arrive today for the rebuild.
The gear on the flywheel and in the pump looked perfect too.

I shot some compressed air though the pressure and intake tubes in the transmission case and no clogs there. So the path is clear and once I re-seal the pump I'll put it all back together; with new gaskets/orings on virtually everything in the system I should hopefully have some good pressure.
If nothing else I learned a ton about how and where the plumbing goes for this system and made sure there were no major visible issues.
 

·
Premium Member
Joined
·
5,674 Posts
can you get hyd oil out the suction tube ??

soundguy
Or if you apply air pressure to the pressure tube do you get air leaking into the transmission?
 

·
Registered
Joined
·
6 Posts
Discussion Starter #10
can you get hyd oil out the suction tube ??

soundguy
well everything is drained out of the system right now. The tractor is on a very slight forward slope and hyd. oil did drip out of both tubes when I pulled off the pump manifold. I did look thru the tubes with a strong LED flashlight and could see all the way thru them and didn't notice anything that looked bad.

John W I know what you mean because I saw your ordeal with those ruptured tubes but I didn't check that yet. I'm hoping that's not my problem after pulling the pump apart and finding some things.

After I split the input and output cases of the pump I think/hope my problem is just worn pump parts. A couple of the springs that hold the input side ball bearings were broken and the pins/seats that are supposed to stop the balls from moving were pretty worn, especially on the pins where the springs were bad.

I'm hoping the refreshed parts in the pump and properly bleeding everything will get it back up to par.
 

·
Premium Member
Joined
·
5,674 Posts
With any luck you are onto the problem, just had to mention it after seeing how much damage water can do to the tubes. Other than the mess where the PO had "worked on it" there were many tiny holes that could not be seen until it was out in strong sun light. I would still try to pressure test it.
 

·
Premium Member
Joined
·
5,674 Posts
Even if there is no problem (hope not) with the tubes, might be able to hear air escaping someplace in the system and help narrow down any pressure leaks.
 

·
Registered
Joined
·
6 Posts
Discussion Starter #14
Well good news finally...
It took some time partly due to family from out of town staying with us and taking forever to scrape old gaskets off of the pump parts, but everything is now working!

I had some challenges disassembling the hydraulic pump especially with the gaskets - they are like glue holding the pump parts together! Once I got everything totally cleaned up and put back together I got massive and instantaneous hydraulic flow from the pressure tube ( I just had to fire it up real quick before I put the main cover back on). I reassembled everything in the system and tested it out a bit with a brush hog type implement and it seemed to hold it steady without any lowering or jumpiness. The single arm hydraulic piston works like a champ too.

Need to hook up the anti-swaybars but ran out of daylight. A lot of work but she is fully functional now! I'm ready to do some mowing and towing.

Next up is probably a new proofmeter or cable - mine is too jumpy to accurately figure my RPM, and to run it a bunch and blow out all of the years of sitting around from her memory!
 

·
Premium Member
Joined
·
5,674 Posts
Great news :thThumbsU
 
1 - 16 of 16 Posts
Top