How to measure hydraulic pressure?

   / How to measure hydraulic pressure? #1  
markedenfield

markedenfield

New member
Joined
Nov 9, 2023
Messages
4
Location
Bradenton, Florida
Tractor
John Deere 790
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
 
   / How to measure hydraulic pressure? #2  
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.
 
   / How to measure hydraulic pressure? #3  
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.
 
   / How to measure hydraulic pressure?
  • Thread Starter
#4  
5030 said:
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.
Click to expand...
I thought so, regarding the special fitting from JD. Is this regarding the class action lawsuit with JD about proprietary stuff?
 
   / How to measure hydraulic pressure?
  • Thread Starter
#5  
J&K said:
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.
Click to expand...
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?
 
   / How to measure hydraulic pressure? #6  
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
 
  • Good Post
Reactions: J&K
   / How to measure hydraulic pressure? #8  
5030 said:
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.
Click to expand...
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.
 
   / How to measure hydraulic pressure? #10  
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.
 
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