860 hydraulics won't lift

Just bought a Ford 860 and now the 3 point arms won't even try to lift. The arms were up and held weight fine when I inspected the unit but like a fool I forgot to actually run them up & down before agreeing to buy.

I'm not familiar with the hundred series hydraulics but things I've checked so far are: Hyd. oil is up to the full line, looks clean and feels like about 30wt. Proofmeter drive cable is missing but the drive itself does turn with the engine. Engaging PTO and moving the draft control lever make no difference.

I don't have a shop manual (yet) and don't want to wait for one if I have to go back to the seller and make my case. Any ideas on what may be going on?

Unless the fellow was really dishonest (I hope not) the fact that the arms were up would make me think that the system works at least a little and I'm just missing something.

Thanks,

Pete P.
Harborcreek, Penna.

I'd be thinking sticky unloading valve.

got a pipe nipple and some hose? unscrew the plug in the 3x5 option cover under the seat.. beware that oil will gush from there and the arms will drop.. screw inthe pipe nipple and then add a hose and aim it over to the hydro fill port.

check the oil out. is it milky or gunky?

if anything other than clean I'd dump in a couple quarts of diesel on top of it and let it circulate thru the hose, then plug it again .. then drain and then refill with straight diesel ( 1 gallon ) and 2 quarts atf fluid, then circulate that for a few minutes, exercising the lift handle.. see if that free's it up. if so.. drain and then refill with utf fluid.

if not.. time to pull the peremiter bolts of the top cover and yank it off.. will need the 13$ gasket and oring kit from CNH to put it back.

post back

soundguy

Sometimes these systems loose hydraulic pump prime.

Loosen the allen head plug on the top of the hydraulic pump with the engine running to see if hydraulic oil escapes. If not, remove it. Oil should be pumped out. If it is not, fill the pump with hydraulic oil through the hole and try it again.

Post back with results.

Dean

Do the trouble shooting with a heavy piece of equipment attached to the three point hitch.

First thing to do is remove the fill cap on the lift housing and then while trying to lift an implement look into the fill hole and you can see the open end of the ram cylinder that does the raising of the lift. If there is a steady stream of oil running out the back of the cylinder the ring/s are shot and need to be replaced.

If it is not leaking there it is possible that the pressure relief valve is leaking. It is easy to access on the Hundred series model tractor. Remove the plate on the right front of the lift housing. This is the remote adapter plate or if it has a remote valve there remove it. The relief valve is going to be the little spark plug looking thingy in one of the holes you can see when the plate is removed. Do not start the tractor with this plate off. Replace the valve. It is not serviceable. I have at times though taken the cap off and found foreign matter under the ball letting it not be able to seat. Do not adjust. If you do take it apart put the cap back only to the solder stop that held it before you took it off. Damage to the pump etc can result if it is altered.


HUNDRED SERIES HYDRAULIC TROUBLE SHOOTING
INCLUDING NAA SERIES.

First you must determine if the pump is pumping correctly.

Most of these round later pumps have two plugs in the pump The one closest to the front of the tractor and in the head of the pump is the one you use to bleed the air out of the pump after air has entered the pump. Air can enter the pump from a bad pump shaft seal and or bearings and it can also enter the pump through a leaky intake O ring or a small hole in the intake pipe. If the hole is above the oil level it will not leak when standing. Usually if it is below the level of the oil the oil will leak out slowly and make a puddle under the tractor according to how big the leak is.

If the pressure side leaks it will not make air go into the pump but will cause a loss of oil.

If it does have the two plugs the one toward the rear of the pump is for priming only. Pour in some oil if needed and put this plug back in. Take the front plug out and start the tractor and run until the oil that is escaping the bleed hole is free of air bubbles. Then shut down and replace the plug and the pump should be operable.

There is the chance that the gear that is the pump driven gear has stripped out it's spline in the center of the gear where it fits onto the pump shaft. This does happen but not often. I suspect that cold oil and a leaky pump shaft seal may be the problem.

It is hard to fix the pump shaft seal if it is in fact leaking. A special tool is needed to pull the roller bearing race cup and the old seal if you save the old race. You can get that race out by welding a bead all the way around the face of the race and let it cool and then it will come out easy as it is shrunk. Then you can drive out the old seal and the old needle bearing. Dirty job but it can be done/

If it is determined that the pump is operating right and supplying enough volume of oil under pressure to the hydraulic system then you may have a sticking unloading valve in the lift ram cylinder housing.

If the lift is jumping/bumping/hiccupping it is caused by the lift trying to hold the height constant with a leak internally of the hydraulic system. The leak must be fixed before these symptoms will go away. Common leaking places are the ram cylinder O ring/s, the pressure relief valve, the O ring on the unloading valve or a blown gasket under the ram cylinder to housing flange surfaces.
On the 53 and up Ford tractors there is a gadget named the unloading valve. It is hydraulically shifted by the movement of the control valve. The control valve does not actually move oil to the ram cylinder. The oil is directed to the ram cylinder by the position of the unloading valve. The Hundred series has the same valve in a slightly different form but performs the same function.
If and when the unloading valve stops moving then the lift won't lift until the problem that is causing this condition is fixed.
A faulty back pressure valve can cause the unloading valve to stick.
The unloading valve can stick on it's own.
The unloading valve has an O ring that can become worn until it will not allow the valve to move.
The pump could have lost it's prime too. The piston pump must be bled by opening the front head plug in the pump and running the engine slowly until all air bubbles are gone from the escaping oil. Stop the engine, replace the plug and start the engine again to see if that fixes the problem. It can!


I would first try bleeding the pump by removing the front pipe plug with the allen head hole in it. Start the tractor and let it idle as slow as possible and when all the bubbles are gone stop the tractor and put the plug back in. You will loose about a half cup usually so put something under the pump to catch the oil.
If it won't work then you must go into the lift and take out the unloading valve and clean it up and replace the O ring with the Ford O ring made specifically for the unloading valve. The old part # was NCA 836B. Don't use a substitute or you will be sorry.
The unloading valve is covered by a plate at the front of the control valve housing just above the control valve. Their is a plug over the valve that must be pulled by inserting a bolt with fine threads into the plug and prying it out with two bars. The valve can then be pushed out with a punch of the appropriate size. Don't strike it with a hammer. The O ring will be on the unloading valve that needs to be replaced.
If you will look around on the other reference pages of the N board etc you can probably find some good views of the lift to give you some idea of what you will be looking at.
When taking the lift control housing off the tractor remove only the bolts that are around the ;outside edge of the housing and do not remove any of the bolt that are inside this circle of bolts. If you encounter a bolt that has fine threads on it put it back where you took it out. The fine bolts hold the cylinder to the cover housing.

LIFT LEAKS DOWN
Install an implement on the lift and raise it.
If the lift leaks down or has a bad case of the hiccoughs it has some sort of hydraulic leak internally. The most common place will be the ram cylinder ring/s. To check the ram cylinder for leaks you can remove the hydraulic fill plug and with a good light observe the open of the ram cylinder as seen through the fill hole. The best light to use is the sun light directed into the hole with a mirror. A good bright flash light will work. If you see oil coming out the back open end of the ram cylinder the rings need to be replaced.

Hiccoughs can also be caused by a leaking O ring on the unloading valve itself. Or if there is a lot of wear in the control valve it can cause it but is much less likely than the ram cylinder rings or the unloading valve or the pressure relief valve.


Also the pilot pressure relief valve can be leaking. It can be accessed by removing the remote hydraulic valve or the valve adapter plate from the top of the hydraulic lift cover that is directly under the seat and on the right side in front of the quadrant mounting point. The relief valve is not serviceable and should be replaced if suspected to be leaking or bypassing.

ON THE NAA SERIES TRACTORS THE RAM CYLINDER GASKET COMMONLY FAILS/BLOWS OUT AND WHEN IT HAPPENS THE LIFT WILL BARELY RAISE THE EMPTY LIFT ARMS.
THE RELIEF VALVE ON THE NAA IS LOCATED ON THE RAM CYLINDER HOUSING POINTING BACKWARDS AND THE LIFT COVER HAS TO BE REMOVED TO ACCESS IT TO REPLACE.
REMOVE THE RIGHT SIDE LIFT INSPECTION PLATE AND OBSERVE IF THERE IS A LARGE VOLUME OF OIL SPRAYING/LEAKING FROM UP ABOVE IN THE AREA OF THE RAM CYLINDER TOP.
Good luck.

Zane

OK here goes --

Opened the hydraulic fill port with tractor running, lift control all the way up in the quadrant, no oil leaking from end of cylinder. Moved draft control lever, no change. Pulled the plug in top of option plate under seat with tractor shut down, no oil escaped. Cranked -- nothing. Ran -- nothing. Removed entire option plate, had two ports with a very small amount of oil seeping, cleaned carefully with clean rag and cranked, then ran, nothing.

Can find no allen head plugs (or any sort of plug) on the top surface of the pump. the only openings appear to be the proofmeter cable drive and a large (1 5/16") plug on the forward face. Pulled this large plug and a spring popped out (ugh.) spring apparently retains a sliding valve of some sort. Cleaned and replaced all, left cap slightly open and cranked -- nothing.

What's next?

Thanks,

pete p.

Does your tractor have the vane type (rectangular) or piston type (cylindrical) pump?

Dean

(quoted from post at 12:08:17 10/17/10) Does your tractor have the vane type (rectangular) or piston type (cylindrical) pump?

Dean

Click to expand...

Vane:


Piston:


Photos, courtesy of John Smith's Old Ford Tractors.

Pretty sure it's vane. The body is apparently three rectangular sections with the rounder proofmeter & drive end making a fourth.

Definitely the vane pump, but with the one-piece cast tube as shown on JMOR's pic of the piston pump. There is also a selector on the pump's right (the outboard side) ranging from fast to slow. It's tough to move but does operate throughout it's range, makes no difference though.

Pete P.

(quoted from post at 13:26:17 10/17/10) Definitely the vane pump, but with the one-piece cast tube as shown on JMOR's pic of the piston pump. There is also a selector on the pump's right (the outboard side) ranging from fast to slow. It's tough to move but does operate throughout it's range, makes no difference though.

Pete P.

Click to expand...

lumbing is model differences.......no concern.

priming:

YEA!!

JMOR's procedure works perfectly. All is well; thanks!

I did call the seller and described my dilemma. I was not accusative, just wanted his experience. He was quite fair and honest -- said the unit worked for him but he had not put many hours on it. He did offer me a rebuilt pump if I couldn't get this one going. I guess I can't ask for more than that.

Thanks again,

Pete P.
Harborcreek, Penna.

Take the rebuilt pump if he offers it. Vane pumps are very expensive and should not loose prime. Most likely your problems are not over.

Dean

Thanks, will do.

Can the vane pump be replaced with a piston type? Any advantages to doing so?

Pete P.

My machine was bought by my dad when I was a kid new. 860, I was pulling down fence line trees today off a crop field while I still had some frost in the ground. I had on the 3 pt scraper blade and was chained to the tower on that when I started augering in to find the blade was down. Now I can lift both lift arms like they are not attached to anything. What did I do to my old work horse?