700 Ford

[Anonymous-0]

I have a 700 Ford on which the three-point hitch will not lift. This started out as an occasional problem. One that could be remedied by bleeding the air out of the hyd. pump. Now, however, no amount of bleeding produces any results. I was told that there is an oring in an outside hydro line and that there is an oring on the inside of the transmission. Either one of which could be causing the problem. Has anyone ran into this before and if so I need some advise on what route to take. Where is the outside line with oring located and what do I remove to get to the inside line? Thanks.

 

[souNdguy]

lets do some diagnosing before we start taking things apart.

1, are you sure pump is bled.. do you have oil a the plug with it running?

can you get oil to the plug ont he 3x5" cover on top of the tranny?

manu times the uinload valve sticks.

is your oil clean and new?

if you are having to bleed alot.. the orings on the pump to manifold or manifold to sump may be bad.. (suction side leaks)

soundguy

 

[Anonymous-0]

I used to remove the plug on the hydro pump to bleed the air. Later I put in a petcock. With the motor running I open the petcock until I get a stream of fluid at which point the lift arms raise. It continues to work until I shut off the tractor for any length of time and then the process must be repeated. As for the oil levels. All are filled to the appropriate level. So oil availability shouldn't be a problem. Tell me more about the suction line.

 

[souNdguy]

well.. since the pump is on the side of the engine, and the resevoir is back behind the trans.. see that manifold that connects the pump over to the front of the trans.. it is the suction and pressure manifold.. from there you find lines running thru the trans, tha mate up at the front of the hyds section.. etc.

soundguy

 

[WA-Hal]

You may have a worn out hydraulic pump drive seal that is letting air into the suction side of the pump. Unfortunately, to repair the seal, you have to remove the bearing cone from the housing, which isn't easy and usually means a new bearing being needed.

Or you could have leaking O ring seals on the hydraulic manifold that goes between the bottom of the pump and the bell housing. That is not very hard to check and change, however the hydraulic oil will run out quickly unless you drain it first. Also, flat, square cut replacement O rings work much better than round cross section O rings.

Something else you might want to try is removing the cover where the PTO control lever is and seeing where the hydraulic oil is going when the engine is running and the hydraulic pump is primed. If there is a lot of oil flow from the top of the hydraulic cylinder/valving casting, there is something very wrong. After rebuilding my hydraulic pump and having the hydraulic manifold off several times, I finally did this test and found that oil was going everywhere. When I removed the top cover, I found that the O ring between the top cover and the high pressure tube had gone bad. Fixing that was fairly easy and cheap--just a couple of new O rings and a gasket. I wish I had done that test before I spent the effort and money to repair the other areas, which probably were fine before I started. Oh well, live and learn! By the way, the top cover is quite heavy and if you have a cherry picker or a well mounted chain hoist, that makes it a lot easier and safer to do the R&R job.

Good luck. HTH

 

[Jim.UT]

It's not worth messing with. Just send that 700 over to me and be done with it.

I'd love to have a 700 and came within $500 of getting one recently. Oh well....

 

[Scott HouTex]

My pump behaved as you describe. I bought a kit and rebuilt the pump, now it works better than it had been lately and holds its prime.
I doubt an o-ring inside the trans would matter,at least for suction(priming) since it should be submerged in oil.
A repair video recommends as a last effort to pressurize the hydraulic reservoir with an air hose on the dipstick hole to force oil up to the pump. I have not tried it, but I would keep the pressure low. This might show where you are getting air thru an o-ring.
Scott

 

[Norm43]

Did you really offer $500 less Jim. You did get to drive her last week and I will gladly let you help with the restoration. In fact you have already with the tips you sent today. I wonder if there is a 700 club somewhere. ... Norm43

 

[Jim.UT]

No, I never made any offer of any kind. I'm just saying I was $500 short of having what I needed at that moment. Thanks for the test drive, though! That is a sweet machine. Did you get the gas valve replaced yet? Might want to park it outside or drain the tank until you do.