# measuring hydraulic pressure



## willy j (Nov 26, 2020)

I'm planning to open the top cover for some lift hydraulics inspection and rehab this winter. I've got a Ford 4000 (Nov '68) with independent PTO and single spool auxillary remote. The IT manual tells me to measure hydraulic pressure using the pressure port on the flow control cover. That apparently requires blocking holes in the auxillary remote plate with gasket material. Why can't I just use the front "lift" port on the auxillary remote as my port to measure pressure?


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## EdF (Sep 15, 2014)

Hey Willie,
Why not plug a gauge with a quick connect into your remote outlet??


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## willy j (Nov 26, 2020)

Thanks for the reply.
Exactly. Why not? Is there some problem with measuring the pressure that way as opposed to doin it the way the manual says to do it? All I want to know before liftin the top cover is whether my pump is generating around 2500 psi at the spec rpm, I think it's 1650.


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## EdF (Sep 15, 2014)

The manual was written for a tractor with a blanking plate installed on your lift cover where you have the remote valves installed. To measure maximum pressure, chain the lift arms down to the axle, raise the lift, and see what you've got.


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## willy j (Nov 26, 2020)

Chain lift arms down to axle, raise lift, push in remote valve lever, and measure pressure at remote pioneer quick connect fitting? I haven't used the remote since I bought the tractor 10 years ago. Just makin sure I understand.


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## BigT (Sep 15, 2014)

Wonderful. You better check the remotes to see if they work first. If so, get some clean fluid in the lines. Try pressure check without chaining down, and if all goes well, chain 'em down.


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## willy j (Nov 26, 2020)

Thanks BigT and EdF. Merry Christmas!

Check my thinkin on this. I've got a leak from the lower tube that goes between the flow control valve faceplate and the hydraulic pump (gear type, independent PTO) faceplate. See pic. I've been told you have to remove the top cover to replace O rings on that lower tube. Is that true?

If I could fix the leak from the lower tube without havin to open the top cover I would just do that, not worry about measurin pressures, and be done with it. I use the tractor for mowin and it does ok with that. I get some occasional hiccups but no problem liftin the 6 foot bushog.

But if I haveta open the top cover I figured I should get some info about whether the pump needs a rebuild while I've got the hydraulics open. So I was told that the top cover has got to come off to fix the leak and that's where I got into the manual's directions about testing pump pressure at the pump faceplate pressure port.

Is it true that measurin pressure at the pressure port on the flow control faceplate as described in the IT manual is the best test for seein if the hydraulic pump is ok? If I measure pressure at the remote, aren't there a bunch of things that can cause decreased pressure even with a good hydraulic pump pressure?

If that's true and it's true that I haveta remove the top cover to take care of my hydraulic fluid leak at the lower tube, I'll go with this line of thinking. First I'll measure pressure where it's easiest, at the remote. If that's roughly 2000 to 2500, I'll remove the relief valve from the hydraulic pump (gear type) and replace O rings and maybe add shim(s). If that gets me to say 2200 or better, I'll proceed with openin the top cover and doin what needs to be done there, and fixin the leak in the lower tube.


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## BigT (Sep 15, 2014)

willie j,
Have a look at the attached link and see if it fits your situation:

https://forums.yesterdaystractors.com/viewtopic.php?t=551944


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## willy j (Nov 26, 2020)

Thanks BigT that thread helps some. Looks like he had the same flow valve and pump and he couldn't get the lower tube to slide up into the flow valve cover, same as me. Maybe I should take some time to get that lower tube cleaned off to bare metal and see if I can get it to slide up into the flow valve cover. Part of me still says even if I fix the leak there, it would make sense to open the lift cover and do a little rehab inside. I'll post as I go along.


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## willy j (Nov 26, 2020)

Cleaned up the lower tube between the flow control valve and the hydraulic pump cover. This is where my leak was. After cleaning paint and crud off the tube I was able to loosen it up and push it up into the flow control cover. Removed the C clip.









That gave me enough room to replace the O ring. 








I also removed the relief valve in the pump cover, inspected it and cleaned it up. 








Put it back together, fluid back in. Leak is gone. 
My initial attempt to measure pressure using the remote was unsuccessful. I'll try chainin the lift arm down. Everything seems to be workin fine.


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## Fedup (Feb 25, 2014)

If you can't measure system pressure using the remote valve, you're missing something. The remote has priority over the lift system so chaining the arms down won't help or solve anything if you test for pressure there. Better go back and revisit your gauge/plumbing/connections. ASSUMING of course, you got the relief valve parts back in place correctly.


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## Ultradog (Feb 27, 2005)

I doubt chaining down the lift arms will accomplish anything.
It is easiest to check pressure by attaching a guage to one of the hoses on your remote valve and crack the handle.
Checking it at the flow control valve requires a special fitting anyway which is harder to find.
Get a guage on it and tell us what your pressure is.


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## willy j (Nov 26, 2020)

Thanks for all the opinions guys. EdF recommended usin the remote and chainin the lift arms down. BigT recommended makin sure the remote works, givin the remote lines a flush, checkin the pressure at the remote and if all goes well, chain the lift arms. Fedup and Ultradog don't think chainin the lift arms is necessary to measure pressure at the remotes. (Fedup thinks I'm an idiot, and he may well be right.) 

Ultra, I've got the fitting to measure pressure at the flow control port and have previously hooked it up to see if I could measure anything without blocking off the remote fluid channels as described in the manual. I was unable to measure any pressure. That's why I used the remote to try to get a pressure measurement rather than takin the remote off and measurin the pressure usin the flow control port before removin the lift cover. I wanted to get some kind of pressure measurement before takin the lift cover off. Now, havin fixed the leak that was my main objective, if everything operates OK I don't have to open the lift cover. But I would still like to know what kinda pressures my pump delivers.

What I did was initially put a male connector with an on/off valve and a hose to a bucket in the remote line that comes from the left front lower remote valve outlet on top of the lift cover. In the manual, it looks like this is the "lift" line of the remote. I flushed fluid out of that line until some cloudiness cleared up. I then put the male connector with a 4000 psi gauge, an on/off valve, and a hose to a bucket. I bled my gauge line. RPMs at 1650. No pressure reading. Raised the lift arms. No pressure reading. Pushed the remote valve lever. No pressure reading. Bled the gauge again. Lowered the lift arms. Pushed the remote valve lever. No pressure reading. Raised the lift. No pressure reading. Pushed the remote valve lever. No pressure reading.

This is the first time I've used this gauge, so that's a possibility. I haven't hooked my bushog up to the lift since I started workin on the tractor, but I'm bettin the tractor will lift it. The relief valve is pretty straightforward. I don't think I screwed that up but if you got any secrets about how that can be screwed up, please let me know. I'll connect the gauge to the other remote and check the pressure there. If that doesn't read anything I guess I'll hook up the bushog and make sure it's liftin it. If it does, I think I gotta assume it's the gauge. I'll post again after I've had a chance to do these things.


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## willy j (Nov 26, 2020)

I decided to just hook the bushog up and see if the tractor would do what I need it to do. That is, run the bushog. I don't have any implements to test the remote valve and have never used the remotes. The tractor ran fine and lifted the bushog as usual. Everything else is as before, except leaks have been fixed. (Leaks from power steering cylinder valve control unit and leak from lower tube that runs between flow control cover and hydraulic pump cover.)








I'm including pics of the setup I used to try to measure hydraulic pressure. This is the same setup described by the IT manual.















I used the same gauge setup with a quick connect and outflow tube to a bucket instead of to the rear axle housing to try to measure pressure at the remote. I plan to return the pressure gauge. I don't think it's working but a nonfunctional remote is another possible explanation. If anybody out there has a 1968 or later Ford 4000 with independent PTO and has measured their hydraulic pressure using a remote, I'd like to hear from them. Quite frankly I'd like to hear from anybody with the same tractor who's measured pressure from the flow valve cover port too. I'm not clear on exactly how to use gasket to block off fluid channels in the base of the remote, as described in the manual. 

For anyone who has a hydraulic fluid leak from the lower tube that goes between the flow valve cover and the hydraulic pump cover, contrary to what most people say, you can fix the leak without takin the lift cover off if it's coming from the lower O ring on the lower tube. I was told that you have to take the lift cover off to fix a leak there. It's a much simpler fix if your leak happens to be from the lower O ring and doesn't require pullin the lift cover.

Thanks to all for the many opinions about how to do stuff. Very interesting.


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## 5horses (Apr 21, 2021)

willy j said:


> Cleaned up the lower tube between the flow control valve and the hydraulic pump cover. This is where my leak was. After cleaning paint and crud off the tube I was able to loosen it up and push it up into the flow control cover. Removed the C clip.
> View attachment 66953
> 
> 
> ...





willy j said:


> I decided to just hook the bushog up and see if the tractor would do what I need it to do. That is, run the bushog. I don't have any implements to test the remote valve and have never used the remotes. The tractor ran fine and lifted the bushog as usual. Everything else is as before, except leaks have been fixed. (Leaks from power steering cylinder valve control unit and leak from lower tube that runs between flow control cover and hydraulic pump cover.)
> View attachment 67037
> 
> I'm including pics of the setup I used to try to measure hydraulic pressure. This is the same setup described by the IT manual.
> ...


I have a 1973 4000 and the pto quit working last year. I did pull the lid and tomorrow I will test the pressure coming out of the valve. How did you make out with your pressure test? I rigged a test gauge, I hope it works. Manual says 150 psi is all that is needed engage the clutch, max pressure is195 so relatively low pressures.On you post, to replace the upper o-ring I lifted the tube up and pulled the pump. That was about 3 years ago and still no leak. If you have any thoughts on my pto please let's know. It does turn in cold weather but when I hook up the brush hog, it doesn't turn at all. I am hoping it is not the clutch pack. The pump is easy to pull


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## willy j (Nov 26, 2020)

5horses, I see ur post. I never did register a pressure and didn't pursue it after I successfully repaired the leak from my flow control downtube and the hydraulic lift was working properly. 

My IT shop manual says that to measure the pressure when using the pressure port on the flow control cover, put the select lever in draft control, lower the 3 point hitch, remove the accessory cover (where ur auxillary remote take off comes off the topplate), make a gasket that covers the 2 oil passages in the outer edge of the lift cover, turn the accessory cover end for end and reinstall with the two long cap screw heads, open pressure gauge shut off valve, start engine and run at 1650 rpm, gradually close the gauge shut off valve while watching pressure gauge. Pressure should gradually move to 2500psi and then stay there steady. 

I had planned to measure the pressure that way because everyone had told me that the lift hydraulic top plate had to be removed to fix the leak from the flow control valve downtube. Since I was able to fix the leak without opening the top plate (the cover), I didn't continue down that trail. I have an remote on my tractor rather than just an accessory cover. I hooked up the pressure gauge to the pressure port on the flow control cover, put the tractor in draft control, lowered the 3 point hitch, ran the engine at 1650 and then higher rpms, and opened the pressure gauge shutoff valve. No pressure reading.

I also tried to measure the pressure from my remote. Again, no pressure reading. I returned the pressure gauge and that was the end of the story. I haven't been able to measure the pressure using either method and stopped wasting my time because the thing was running fine. But it would have been nice to have been able to get a pressure reading. I'm sure I'll come back to this at some point in the future when I have to remove the top plate (the hydraulic lift cover) to fix hydraulics.

I know that's not any help to you but that's the story. Good luck with your project. There should be somebody in here that can help you.


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