Ford 850 Hyd problems

[glweder]

Hello,

I have a ford 850 that I love but for the last year has experienced intermittent hyd' leaks. And by leaks, I mean it pours! I took the lift assembly apart last year, completly cleaning out the resevoir, replaced any o-rings I could. I also rebuilt the hyd-pump. The problem started when I borrowed a friends tiller for some landscaping work, the tractor started leaking bad around the pump mount flange. I did all the above work but it continued to leak. This spring I used the tiller again and noticed it didn't leak at all. Fast foward to last week when I was using the tractor to dig some post holes; it started leaking like a mother... again. The leak is at the same mounting flange as before. Everything is tight and I don't see any cracks.

My guess is my some debrie has plugged something (I cleaned alot of gunk out of the reservoir) and the system is creating too much pressure?


Thanks for any feedback.

George

 

[AKKAMAAN]

Hello,

I have a ford 850 that I love but for the last year has experienced intermittent hyd' leaks. And by leaks, I mean it pours! I took the lift assembly apart last year, completly cleaning out the resevoir, replaced any o-rings I could. I also rebuilt the hyd-pump. The problem started when I borrowed a friends tiller for some landscaping work, the tractor started leaking bad around the pump mount flange. I did all the above work but it continued to leak. This spring I used the tiller again and noticed it didn't leak at all. Fast foward to last week when I was using the tractor to dig some post holes; it started leaking like a mother... again. The leak is at the same mounting flange as before. Everything is tight and I don't see any cracks.

My guess is my some debrie has plugged something (I cleaned alot of gunk out of the reservoir) and the system is creating too much pressure?


Thanks for any feedback.

George

Is it leaking around the mounting flange of the pump??
What type of pump/system is it on that F850??

One thing I can imagine, is that if you have a piston pump/constant pressure system, with oil in the pump casing/housing, and the drain line from the housing to tank is restricted, a higher pressure in the housing will blow the shaft seal....
If this piston pump is way worned out, there will be internal leakage inte the housing and these 1/4" drain lines cant handle all that flow....

If shaft seal is blown, then this is your problem...

If this piston pump applies on your case, check shaft seal....check these drain lines, clean them, make sure they are not squezzed or bent...if drain are going through the filter, make sure filter is not restricting.....make sure reservoir vent is working....
Drain lines are sometimes designed to by pass filter of this reason....drain line HAVE TO BE VERY LOW, OR NO PRESSURE AT ALL....ONLY A FEW PSI AT THE MOST

 

[glweder]

Is it leaking around the mounting flange of the pump??
What type of pump/system is it on that F850??

One thing I can imagine, is that if you have a piston pump/constant pressure system, with oil in the pump casing/housing, and the drain line from the housing to tank is restricted, a higher pressure in the housing will blow the shaft seal....
If this piston pump is way worned out, there will be internal leakage inte the housing and these 1/4" drain lines cant handle all that flow....

If shaft seal is blown, then this is your problem...

If this piston pump applies on your case, check shaft seal....check these drain lines, clean them, make sure they are not squezzed or bent...if drain are going through the filter, make sure filter is not restricting.....make sure reservoir vent is working....
Drain lines are sometimes designed to by pass filter of this reason....drain line HAVE TO BE VERY LOW, OR NO PRESSURE AT ALL....ONLY A FEW PSI AT THE MOST

Thanks for the feedback: The pump is the piston style pump, and yes it is leaking around the mounting flange. When I rebuilt the pump I didn't notice any wear or play at all. I agree there must be a restriction somewhere, just not sure where to start. There is no filter in the system, so I'm guessing some junk is intermittently plugging something. I spent alot of time last fall cleaning crap out of the reservoir. but some obviously is still somewhere in the lines.

 

[AKKAMAAN]

Thanks for the feedback: The pump is the piston style pump, and yes it is leaking around the mounting flange. When I rebuilt the pump I didn't notice any wear or play at all. I agree there must be a restriction somewhere, just not sure where to start. There is no filter in the system, so I'm guessing some junk is intermittently plugging something. I spent alot of time last fall cleaning crap out of the reservoir. but some obviously is still somewhere in the lines.

You have a piston pump...
Do you have that 3rd hose from the pump casing???
Thats is the drain line!!
MAKE SURE THAT DRAINLINE IS CLEAN, all the way from inside the pump casing to the tank, also allow no kinks or sharp bends...
If it is leaking now, you have to replace that pump shaft seal....
Next time you are ready to start up the pump, do not not have the drain line attached yet, and fill the casing with clean oil before starting up....NEVER DRY START A PUMP OR A MOTOR....when casing is filled to the hole, make an arrangement so you can collect 100% of oil coming out during 30 seconds of high pressure load on pump...that amount of oil will tell how worn your pump is....an ok pump should not leak more than some few cc of oil per minute....if a significant larger amount of oil is coming out during this test, something is wrong with your pump, either worned out or assembled incorrectly.....

Normal wear may be hard to detect for a non-professional pump "technician"...

The above test also apply on hydraulic motors...
Do all internal leak testing testing at normal operating temperture (viscosity reasons)....

BTW how old is this tractor?

 

[MikesTractor]

Is it leaking at the 3 bolt flange? All that seals the pump to the hydraulic manifold flange is 2 square shouldered o-rings. Make sure that you have the right o-rings and that the 3 bolts are tight.

Please post pics if this isn't the problem.

Mike

 

[Soundguy]

I don't think you are familiar with the engine mounted hyd pump on an 850.. or at least it doesn't sound like it...there is no 3rd line.. there is a hyd manifold that runs from it tot he trans center feedthru lines.. at the hyd section there is a relief valve...

the pump is cam driven, and if it is gushing oil at the gear drive, I'd think a shaft seal was gone.

I included a exploded diagram of the pump

soundguy

You have a piston pump...
Do you have that 3rd hose from the pump casing???
Thats is the drain line!!
MAKE SURE THAT DRAINLINE IS CLEAN, all the way from inside the pump casing to the tank, also allow no kinks or sharp bends...
If it is leaking now, you have to replace that pump shaft seal....
Next time you are ready to start up the pump, do not not have the drain line attached yet, and fill the casing with clean oil before starting up....NEVER DRY START A PUMP OR A MOTOR....when casing is filled to the hole, make an arrangement so you can collect 100% of oil coming out during 30 seconds of high pressure load on pump...that amount of oil will tell how worn your pump is....an ok pump should not leak more than some few cc of oil per minute....if a significant larger amount of oil is coming out during this test, something is wrong with your pump, either worned out or assembled incorrectly.....

Normal wear may be hard to detect for a non-professional pump "technician"...

The above test also apply on hydraulic motors...
Do all internal leak testing testing at normal operating temperture (viscosity reasons)....

BTW how old is this tractor?

 

[AKKAMAAN]

I don't think you are familiar with the engine mounted hyd pump on an 850.. or at least it doesn't sound like it...there is no 3rd line.. there is a hyd manifold that runs from it tot he trans center feedthru lines.. at the hyd section there is a relief valve...

the pump is cam driven, and if it is gushing oil at the gear drive, I'd think a shaft seal was gone.

I included a exploded diagram of the pump

soundguy

I kinda started to suspect there was something wrong, and after a couple of Googles on Ford 850 pump...... could see they have history back in 1950's?? so it is a pretty old one then....newer piston pumps/motors are built with piston unit inside a casing.....Well OK, this is a forum and we all learned something hopefully.....

BTW from what year is this tractor??

Hope you get some help with your pump now....

 

[Soundguy]

I kinda started to suspect there was something wrong, and after a couple of Googles on Ford 850 pump...... could see they have history back in 1950's?? so it is a pretty old one then....newer piston pumps/motors are built with piston unit inside a casing.....Well OK, this is a forum and we all learned something hopefully.....

BTW from what year is this tractor??

Hope you get some help with your pump now....

It's not my pump.. though i do own an 850..... and 9 other various fords fromt he mid 40's and up

the ford xx0 series were model years from 55 thru 57.

soundguy

 

[glweder]

Is it leaking at the 3 bolt flange? All that seals the pump to the hydraulic manifold flange is 2 square shouldered o-rings. Make sure that you have the right o-rings and that the 3 bolts are tight.

Please post pics if this isn't the problem.

Mike

Yes thats exactly where its leaking. I replaced those o-rings and remounted it several times to make sure its on square and tight.

 

[glweder]

It's not my pump.. though i do own an 850..... and 9 other various fords fromt he mid 40's and up

the ford xx0 series were model years from 55 thru 57.

soundguy

My 850 is a 57'. Great tractor, uses alot of gas though. Soundguy you think the oil seal for the drive shaft is worn? I see it in my service manual and the instructions show the use of a set of special tools to remove and install the needle bearings and oil seal; do you know if this can be done w/o these tools?
Thanks for the help.

George

 

[Soundguy]

If you are leaking at the manifold flange, then I'd think it is the flat face orings... if you have repalced them with regular orings.. they may not seal.. get the real flat faced ones.

as for rebuilding without the nuday tools.. I've heard of it done.. but not done it myself.

I believe RickB knows how to do it.. he's a NH man..

soundguy

 

[MikesTractor]

glweder,

You said that you rebuilt the pump. Based on Soundguy's diagram, did you remove the head #2? If you did, did you remove the valve plate #8? The old gaskets #7 & #12 need to be removed completely so the new ones can seal. Also, check this area for a gasket leak if you didn't remove the head. Be very careful taking the head off. There are several small balls and springs that can fall out.

While you have the head off and apart, remove all of the old paint so that you can check it for cracks. There is a threaded plug #3 in the side of the head. Check around it, I have seen cracks around them sometimes. The head is where the pressure is built, so if you have a pressure leak, it will be near this end.

If the shaft seal #24 is bad, it usually lets the pump suck engine oil into the pump, or it sucks air, causing you to lose hydraulic pressure, since it is on the suction side of the pump.

Since you have a pressure leak, I would concentrate on the head. Make sure that the manifold flange is square to the pump flange. Make sure that you have the right o-rings for the manifold flange. They are flat faced, or square shoulder as has been said before. Make sure that the bolts and threaded holes are not stripped. Also, check the aluminum manifold to make sure it isn't cracked.

Ask questions and post pics as you go. There is enough combined talent on this forum to help you fix this.

Mike

 

[MikesTractor]

I see it in my service manual and the instructions show the use of a set of special tools to remove and install the needle bearings and oil seal; do you know if this can be done w/o these tools?
Thanks for the help.

George

I don't know how many I have rebuilt, but only one without the proper tools. After that one I bought the right tools for the job. Much easier and quicker.

Mike

 

[glweder]

I don't know how many I have rebuilt, but only one without the proper tools. After that one I bought the right tools for the job. Much easier and quicker.

Mike

Thanks for the input; When I "rebuilt" the pump last fall, I replaced the balls, springs and various o-rings that came with the kit.

Tonight is the first time I taken the "tach" end of the pump off to replace the oil seal. I asked the parts guy at NH if I could do it w/o the tools and was told it should be ok. Anyway, I made a mess of the needle bearing and old seal trying to get things apart tonight. I think I will bring it to dealer and have them press tthe old seal out and install new bearings and seal.

I will post an update when I get it back and install.

Thanks again,

George

 

[glweder]

I got the "bottom" end of the pump back from the dealer. They replaced the needle bearing, oil seal, bearing race and also the drive shaft which was worn.
I assembled the pump and reinstalled today and it leaked immediately when I fired up the tractor. I removed the pump and took the head end apart to inspect. Everything looked fine. When I remounted I got a light and inspection mirror and now I can see the pump is leaking at the head connection. I took the unit apart again and torqued the six bolts very carefully with the same result. There seems to be alot of pressure in the system, when I shut it down I can here the pump pushing air and fluid out at the head joint.

I know I am rambling here; Let me know if you have any suggestions.

Thanks,

George

 

[shiftyguy]

You may have a plugged line or some kind of problem with the 3PH controls.
My pump has a gauge at the output of the pump. The only time I see pressure is when the 3PH is moving. Any other time the oil is free flowing and no pressure is seen on the gauge.

 

[J_J]

I got the "bottom" end of the pump back from the dealer. They replaced the needle bearing, oil seal, bearing race and also the drive shaft which was worn.
I assembled the pump and reinstalled today and it leaked immediately when I fired up the tractor. I removed the pump and took the head end apart to inspect. Everything looked fine. When I remounted I got a light and inspection mirror and now I can see the pump is leaking at the head connection. I took the unit apart again and torqued the six bolts very carefully with the same result. There seems to be alot of pressure in the system, when I shut it down I can here the pump pushing air and fluid out at the head joint.

I know I am rambling here; Let me know if you have any suggestions.

Thanks,

George

With no valves activated, there should not be any or very low pressure on the system, as the hyd fluid is just circulating around through the in and out ports of the valves.

If you know the operating pressure of your pump, let me suggest that you test the pump before you put it in service, and this is how I would do it. Install a tee with gage, and a needle valve on the pump output and run the hose back to tank. Start the tractor, and turn the needle valve in until it approaches pump operating pressure, and checks for leaks. Keep the pressure 200 psi below the max pump pressure.

To check and set relief, do this.

Disconnect one of the cylinder work ports, add a nipple, a tee with gage, and connect cylinder hose to the gage. Start the tractor, and check for flow and leaks. Activate the cylinder with the gage in line. and hold it to max , to show relief pressure. Relief pressure is usually set lower than pump pressure by 100 to 200 psi. Some people try and squeeze all the pressure they can get, but that is risky. If all the parts and gaskets were installed correctly, and the bolts on the pump was torqued correctly, the pump should not be leaking.

If everything is hooked up , and you start the tractor, and the pump is leaking, with nothing activated, the pump is not put back correctly, or there is a crack, or loose fitting somewhere. There should be no pressure at this time. If you have pressure at idle, then something is blocking the flow of fluid, perhaps a quick disconnect going to a valve, or stuck spool in a valve.

 

[Soundguy]

Would be very difficult to do this on that engine mounted hyd pump due to the manifold connection it uses.

soundguy

 

[J_J]

Is there not a hose coming into the control valve?

 

[Soundguy]

No(*).. this pump mounts directly to the side of the engine ( cam driven ).. then there is a hydraulic manifold that bolts to the base of the front of the pump, and then bolts to the center section.. there are feedthru tubes in the center section to pipe oil back to the rear section.. at the base / entrypoint of the rear section is the relief valve.. oil then travels up the side of the rear section and is fed into the lift cover. from there it takes a path so that remote hyds can be tapped via a blank off plate, and otherwise it is fed to the unloading valve and mounted 3pt hyd cyl.

there are no external 'hoses' on this setup.. just internal passageways, piping and manifolds.

in the attached pics, the piston pump has a manifold that bolts to it.. the manifold also bolts to the trans.. in the trans pic, you can see the oring 4/5 for the seal.. in the rear housing pic, you can see the other side of the feedthru tubes with oring 7/8 and the relief valve 13.

in the liftcover pic you can se ethe blank plate I speak of.. and the lift cyl pic you can see how the cyl attaches to the underside of the cover... it's all oring and gasketed connections here..

soundguy