Ford 8600/9600 hydraulic issue

This is about a 1973 Ford 8600 rear half, with a 9600 front half, from the clutch forward. Dual power, no cab.

About a month ago I was spraying, and the main lift would barely pick up the 200 gallon 3pt hitch sprayer. I could rev it up and it would raise, and the pump would cut off and it would stay in place. It eventually got to where it would not pick up at all. We did still have some hydraulic pressure and we were baling hay later and the pto went out.

We called our local mechanic and he was busy, and contacted another competent mechanic who has little experience on 8600's, but lots on 5000's, so we felt he could do the job or replacing the pump. He came over and replaced the pump, bolted everything back up, and no pressure.

We added an extra 5 gallons of oil TEMPORARILY so that if the pickup tube was out, it would still pick up and prime... no luck.

We got another new pump, and repeated, still no luck.Just got through with that today. Got zero pressure on a guage at the rear remotes, although you could feel some oil flowing.

Today, we pulled the filter on the LH side, and ran the camera through the intake tube all the way to the pump, and you can see that the pickup tube is property installed. That is not our problem unless there is a hairline crack that is pulling air. We did install a new o ring at the tube/pump interface.

Tonight, for kicks I pulled apart the old pump and found that the small pump that operates the pto and dual power was fine. On the main pump the steel front gear sleve in the aluminum housing was worn through, the shaft was galled, and the aluminum housing was ovalized. That was the problem. It never really screamed though, even when it would not work. However, there was a lot of metal in the filter that was shedding from the pump.

A local guy with lots of knowledge said that we have a problem somewhere in the main lift. Either a blown o ring in the main lift cylinder, or we think that there might be a piece of metal in one of two valves attached to the main lift cylinder allowing oil to bypass.

Since the rear lift would hold the 2000lb sprayer once it was up, I think the o-ring is probably OK.

What he said is that the main lift gets oil first, and something is going on to where the main lift is calling for oil, but not building pressure. That also keeps any oil from going to the rear remotes.

He also suggested running for a half hour or so and check temperatures of the lift housing, and the oil to see if there is any heat generated to get a clue of where the bypass/leak is occuring.

So we are considering pulling the lift cover off next to check that o-ring, and pull the 2 valve bodies in the main lift assembly to check for metal holding something open.

Whew! That is lots of info, but any comments, suggestions would be appreciated.

Thanks!

D Lee
Ford fan in GA
1973 96/8600
1976 8600
1969 5000
1964 5000 with loader

I would think that the 3-point would NOT affect the remotes if the 3-point handle was down. If I'm right, I'm guessing your problem to be further upstream, like in the relief valve area.

I would get a special test fitting and test the pump and relief valve directly. Look here for more info: http://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=ford&th=565343

Bern,

So this tool would tell us for sure whether there is flow from the main pump and how much if we hook up a flow meter to it.

I was thinking there should be a way to figure that out in cases like this.

I will get the appropriate fitting from the local hydraulic shop and see what happens. IF, the pump is not drawing oil, I don't want to run it too much.

Another question...Is there a check valve on the intake end of the oil pickup tube that supplies the main pump? It seems like a lot of suction is needed to pull that oil up, and through the filter to feed the pump.

The other thought I had was to crank up the tractor for a minute, shut it off, and them quickly pull the LH intake filter off, and check for oil in the intake tube. I don't remember a lot of oil on the flexible camera goose-neck when I pulled it out yesterday after we checked the intake/pump interface. I didn't take the filter off so I did not see for sure.

It will be a few days before we do any more on this. Getting rye planted.

Thanks for the response.

D Lee
Ford fan in GA

(quoted from post at 20:53:29 10/09/14) I would think that the 3-point would NOT affect the remotes if the 3-point handle was down. If I'm right, I'm guessing your problem to be further upstream, like in the relief valve area.

I would get a special test fitting and test the pump and relief valve directly. Look here for more info: http://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=ford&th=565343

Click to expand...

There is no check valve that I am aware of in the inlet line.

I doubt you'll find that fitting at your local hydraulic shop. It's a NH special tool.

OK, It has been a while, but I got the right fitting to fit the pump test port, and installed it in the port, and we are getting no flow out of the pump.

Then, I removed the filter on the LH side, and you can see all the way through the intake tube to the pump gears. We pulled the fuel cut off and bumped the starter. The pump is turning.

Then I took my inspection camera, and we ran it down the tube at 12,-3 - 6- and 9 o'clock. The transition between the tube and pump is tight. I don;t think that is the problem. We used a new o-ring on the install.

I know there is no flow, because there was no oil in the filter, or the supply tube, and also when the mechanic put the pump on, he used some green JD corn header grease on the pipe and pump. You could still see the green grease in the pipe just before the pump transition.

We cleaned the main relief valve to make sure there was no metal in there.

This is a mystery, unless there is a crack or leak on the filter end of the supply tube that is preventing the pump from priming, or an obstruction on the intake from the oil reservoir. Seems like it would have to be a big leak with the volume that pump supplies.

Any comments, suggestions welcome before we tear into it again looking for a problem.

Ford Fan in GA
D. Lee

(quoted from post at 19:53:31 10/10/14) There is no check valve that I am aware of in the inlet line.

I doubt you'll find that fitting at your local hydraulic shop. It's a NH special tool.

Click to expand...