How to measure hydraulic pressure?

[markedenfield]

I have a 2002 JD 790 with a front end loader that refuses to lift (what appears to be) much weight. I'm not real sure exactly how much weight it lifts (max is between 700-750). Since this is my first tractor though, shouldn't it be able to at least lift the front wheels off the ground? It won't. The loader however, does go up and down. So where do I start diagnosing this? I've checked the resevoir and it appears full. Can I measure the pressure? Thanks

 

[5030]

You'll need a special fitting and a glycerin filled pressure gage with at least a 3000 psi rating. I got my fitting and gage from Motion Industries but I suspect with a JD, you'll have to source the fitting at your local overpriced JD dealership.

 

[J&K]

Just get a hydraulic pressure guage and a short piece of hydraulic hose. A quick coupler and hook to one of the loader ports and check pressure. My 790 was low and shimmed and increased pressure. I increased it about 300psi and made a big difference. If I remember right you don’t want to go over 2500psi. I got shim kit at JD dealer and think it was around $3.

 

[markedenfield]

You'll need a special fitting and a glycerin filled pressure gage with at least a 3000 psi rating. I got my fitting and gage from Motion Industries but I suspect with a JD, you'll have to source the fitting at your local overpriced JD dealership.

I thought so, regarding the special fitting from JD. Is this regarding the class action lawsuit with JD about proprietary stuff?

 

[markedenfield]

Just get a hydraulic pressure guage and a short piece of hydraulic hose. A quick coupler and hook to one of the loader ports and check pressure. My 790 was low and shimmed and increased pressure. I increased it about 300psi and made a big difference. If I remember right you don’t want to go over 2500psi. I got shim kit at JD dealer and think it was around $3.

If I get a hydraulic hose with a aquick coupler, is the coupkle factory connected to the guage? I'm sure a hose clamp wouldn't withstand the PSI would it? And the shims, do they come with instructions?

 

[hiddentacocatneddih]

DO NOT hose clamp any hydraulics.

Just get couple fitting and put in a T where you can add a gauge on the output of the pump

 

[kennyd]

You can watch our video here, and we sell gauges too.

Hydraulic Tools - BoltOnHooks LLC

Bolt-On Hooks and Hydraulic Tools for compact tractors.

www.boltonhooks.com

 

[kennyd]

You'll need a special fitting and a glycerin filled pressure gage with at least a 3000 psi rating. I got my fitting and gage from Motion Industries but I suspect with a JD, you'll have to source the fitting at your local overpriced JD dealership.

Why do you continue to spread fake news with your hatred for JD?

His 790 uses either a 1/4" 5675 "AG" style fitting, or a 3/8" 7241B type depending on the serial number. Both are standard across many tractor OEM's.

 

[kennyd]

I thought so, regarding the special fitting from JD. Is this regarding the class action lawsuit with JD about proprietary stuff?

Please ignore that poster, he has an obvious bias against JD. Plus, he is 100% wrong.

 

[hiddentacocatneddih]

It's a shame more people dont think poorly of JD due to their attacks on dealerships and owners

Any hydraulic shop should be able to source the fittings or even tractor supply.

 

[Egon]

I thought so, regarding the special fitting from JD. Is this regarding the class action lawsuit with JD about proprietary stuff?

)

 

[Egon]

It's a shame more people dont think poorly of JD due to their attacks on dealerships and owners

Any hydraulic shop should be able to source the fittings or even tractor supply.

If it’s threaded or there is tubing, pipe or hose there will be fittings, gauges and valves that will work At the required pressures. Tubing or threaded fitting will be the easiest to break into.

 

[JCoastie]

@markedenfield I had similar questions. Here is what I did

measure hydraulic pressure at any fitting?

Am I correct in thinking that hydraulic pressure 'should' be the same at every tractor accessory fitting? I understand that flow may be different, but is pressure the same throughout? I see people measuring PSI directly at the loader valve, and my fittings on that valve are smaller than the...

www.tractorbynet.com

Was pretty simple really,the cost was $38 from amazon, I have 1/2 fittings, you might have a different size.
Parts:

Amazon.com

Amazon.com

Amazon.com

 

[markedenfield]

You can watch our video here, and we sell gauges too.

Hydraulic Tools - BoltOnHooks LLC

Bolt-On Hooks and Hydraulic Tools for compact tractors.

www.boltonhooks.com

I watched the video - very informative - thanks. I'm new at this so bear with me although I am mechanically inclined. What thread type does the hydraulic port on my JD have? Are they NPT?
And I understand about some people being biased about certain products. No biggie. I just scroll on past.
Do you have any videos on repairing/upgrading the hydraulic pump on my JD? If not, do you know where I could find one? Someone mentioned shims? Again, thanks for your help. Kenny, right?

 

[JCoastie]

Your tractor should loader have quick connects on it (judging by old google images pics), and that's your best option, get a matching quick connect, you don't want to open and screw anything into your hydraulic port.

Disconnect a quick connect to your loader (just need 1) replace it with the quick connect on the gauge, take your reading (adjust the relief valve if necessary) then disconnect the gauge and hook the loader back up. Should be done in 2 minutes, no tools required.

 

[kennyd]

I watched the video - very informative - thanks. I'm new at this so bear with me although I am mechanically inclined. What thread type does the hydraulic port on my JD have? Are they NPT?
And I understand about some people being biased about certain products. No biggie. I just scroll on past.
Do you have any videos on repairing/upgrading the hydraulic pump on my JD? If not, do you know where I could find one? Someone mentioned shims? Again, thanks for your help. Kenny, right?

1) You needn't worry about the threads, you will be plugging into one of the ports like the video shows.
2) JD uses mostly ORB (o ring boss) threads for their QD's
3) No, we don't.
4) No, I don't.
5) For the 790, you would add shims to increase the PRV pressure, lots of info on that if you search here and on Google.

6) Yes, I'm Ken/Kenny

 

[rScotty]

Use a pressure gauge of around double the psi rating of what you expect to measure. You are looking at 2000 to 3000 psi, so the appropriate gauge is a standard 5000 psi.
Lots of people monitor their FEL pressure. You can leave the gauge in the circuit, I do. Although if you do that you may want to use an unfilled gauge to avoid freezing. For the accuracy you are wanting, either flled or unfilled gauge will be fine.

 

[5030]

Why do you continue to spread fake news with your hatred for JD?

His 790 uses either a 1/4" 5675 "AG" style fitting, or a 3/8" 7241B type depending on the serial number. Both are standard across many tractor OEM's.

I don't 'hate' anything or anyone. I used to have JD tractors and you and both know that JD parts are super expensive.

One thing I do dislike is your snarky comments however.

Just because I won't buy your overpriced hooks when I can easily fab up my own for a helluva lot less don't mean you need to keep posting childish comments. That goes for the rest of your overpriced junk as well.

Get a life. I'm sure you'll report me for this comment, just like you to play that crap.

 

[kennyd]

No reporting @5030 , but I think most can see who is acting 'childish' here.

Many other brands have expensive parts too, but luckily they are still available.

 

[coast40]

I bought a set like this for testing my dozer and excavator. $50-70
https://www.amazon.com/VEVOR-Hydraulic-Excavator-Construction-11Couplings/dp/B07HQ3CZ1B/