JD 790 300 loader
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kebo
Elite Member
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- 2001 John Deere 790 4x4, bar tires
Read back up a few posts. Most are setting them to 2500PSI or slightly less. I plan to set mine to about 2450 when I get the chance to do it. I have everything needed to upgrade mine, except time.
dirt ditch
Veteran Member
Right now my 790 is set at 2400psi @ 2000rpm which works well for me.
I don't know what the upper pressure limits are on the 790 / 300 hydraulic system. A couple bad things I can think of from too much pressure are, blowing seals, buckling the cylinder tubes when the loader is raised with a heavy load, or tipping the tractor over.
If it was me I'd back the pressure off then see how that works for awhile. If you still need more lifting ability then may have to think about a larger tractor.
just my $.02
I don't know what the upper pressure limits are on the 790 / 300 hydraulic system. A couple bad things I can think of from too much pressure are, blowing seals, buckling the cylinder tubes when the loader is raised with a heavy load, or tipping the tractor over.
If it was me I'd back the pressure off then see how that works for awhile. If you still need more lifting ability then may have to think about a larger tractor.
just my $.02
kebo
Elite Member
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Well, I was all set to jack up the pressure on my 790 yesterday and I had the gauge, the o-rings, and two shim kits. I disconnected one of the hoses to the FEL and went to pop in the gauge only it didn't fit. I bought the pressure gauge and the quick connect fitting for it at a hydraulic shop that's right on my way to work. They guy gave me the one he thought would fit my quick connect hoses, but it's just a bit too large. See the picture below. It looks like the fitting on my tractor is about 2/3rd's the diameter of the one he sold me. So, I'll be stopping by there on Monday to get the right fitting, or a refund. When I bought this fitting, I didn't have a picture or a part number to show him so it's a little dumbness on my part. But, I have a picture of the correct fitting that was posted here on this thread, and a measurement to take back, so hopefully he can match it up and swap it for the right one. Maybe next weekend I'll get this done!
dirt ditch
Veteran Member
Perhaps this will help?
The quick couplers I bought at the JD parts counter for my gauge are marked as follows.
MALE: Pioneer 4010-2P
FEMALE: Pioneer 4050-2P
The quick couplers I bought at the JD parts counter for my gauge are marked as follows.
MALE: Pioneer 4010-2P
FEMALE: Pioneer 4050-2P
Willl
Elite Member
JD's QC are standard size ?, don't quote me but I thought they where JD only size. Proprietary like.
dirt ditch
Veteran Member
Can't find the sales receipt for them, but my better half was the one who went to JD and bought them. She told the parts clerk she needed quick couplers for a 2007 790, He had to look them up before he could get them for her. The Pioneer quick couplers worked.
Willl
Elite Member
This is interesting.
JD's part # for 'their' QC male fitting is AM37983
A Google search on AM37983 pulls up this PDF of Goodyear fittings.
A search in that PDF for "AM37983" pulls up what I believe is Goodyears match for that JD fitting, (GY's # QS41-02P)
Now this is the interesting part.
If you do a search for "QS41-02P" in this same PDF from GY, you get many matches of this fitting under the different brand names/numbers.
Including your Pioneer # Dirt.
Give it a try.
Kebo, maybe take this PDF and highlite all the matches, print and take it with you.
"Proprietary like", maybe not.
JD's part # for 'their' QC male fitting is AM37983
A Google search on AM37983 pulls up this PDF of Goodyear fittings.
A search in that PDF for "AM37983" pulls up what I believe is Goodyears match for that JD fitting, (GY's # QS41-02P)
Now this is the interesting part.
If you do a search for "QS41-02P" in this same PDF from GY, you get many matches of this fitting under the different brand names/numbers.
Including your Pioneer # Dirt.
Give it a try.
Kebo, maybe take this PDF and highlite all the matches, print and take it with you.
"Proprietary like", maybe not.
foggy1111
Elite Member
There was some confusion when I got my coupler from the JD dealer too. Mine are Pioneer couplers too, but these are smaller couplers than commonly found on other tractors.....and if I remember right they had both the O-Ring coupler (straight pipe threads) and one with tapered pipe threads available.
I got one with the straight threads (for O-Ring seal) and picked up an O-Ring type fitting at the automotive store to use with it, and reduced from there to fit the gauge (my auto store makes hydraulic hoses too...hence a large selection of fittings).
I got one with the straight threads (for O-Ring seal) and picked up an O-Ring type fitting at the automotive store to use with it, and reduced from there to fit the gauge (my auto store makes hydraulic hoses too...hence a large selection of fittings).
kebo
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Thanks guys for the replies. I will print out the pdf file and take it with me when I stop by the hydraulic shop. Now that I have something to show him, hopefully the guy will have what I need. If not, I guess I'll be making another trip to my JD dealer.
kennyd
Advertiser
They are not proprietary, they are made by Pioneer. My tractor uses the 1/4 size and I can buy them at TSC.
kebo
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Today was the day! Finally had everything together and even the weather cooperated, about 83 and sunny here. NICE!! Took one of the loader hoses loose and connected the gauge. Cranked it up and ran it up to about 2400rpm's and got a reading at just about where it should be, slightly over 2000psi. So, shut it down and bled off the pressure again. Took the cap off of the relief valve and pulled it off. The little cylinder thingy in it with the factory shims stayed in. So, tapped the cylinder thingy out and added a full pack of (4) shims which had two thick ones and two thin ones in it. Because I had read that some folks were adding an extra shim, I pulled a thin one out of the 2nd pack I bought and put it in as well. Got it all back together with a new o ring and fired it up. Took a reading and it was dead nutz on 2500psi. I didn't get to do any real loader work with it after that, but I'm gonna run it like that for a while and see how it goes. If it seems to be overdoing it, I'll take the last little shim out and see what it drops it down to. Thanks for all the help!
kennyd
Advertiser
2500 PSI seems to be the magic number for the 790's.
dirt ditch
Veteran Member
seems to be a good compromise between performance & safety.
Got rid of the last of the old bales yesterday.
The 790/300 did a great job loading and unloading bales even though a couple of them were still quite heavy.
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Barely Smokin'
Silver Member
Man, this is great info on the pressure relief shims. Couple thoughts:
- I've noticed big improvements in hydraulic power after an oil/filter change. Maybe file that in the obvious but easily overlooked file.
- Also, and I apologize if I've missed this, but does anyone have a feeling for what the load capacity (regardless of PSI setting) is on the mechanical loader assembly itself? Whatever 2500 PSI will lift? I usually have an attachment on the back and, with the low factory PSI setting, I've never lifted the rear tires off the ground although I overload it all the time with pallets of brick, piles of logs, trees, etc. Occasionally, though, I'll go at a stump from an angle and maybe tweak one rear tire off the ground...and I always wonder what the "breaking point" is.
- I've noticed big improvements in hydraulic power after an oil/filter change. Maybe file that in the obvious but easily overlooked file.
- Also, and I apologize if I've missed this, but does anyone have a feeling for what the load capacity (regardless of PSI setting) is on the mechanical loader assembly itself? Whatever 2500 PSI will lift? I usually have an attachment on the back and, with the low factory PSI setting, I've never lifted the rear tires off the ground although I overload it all the time with pallets of brick, piles of logs, trees, etc. Occasionally, though, I'll go at a stump from an angle and maybe tweak one rear tire off the ground...and I always wonder what the "breaking point" is.
DWCox
Silver Member
I added the shims (790 with 300 loader) and checked the pressure. It is ca. 2550-2600 psi, which is squarely within JD's spec. listing of 2422-2698 psi for the 3005.
The performance of both the loader and 3-point hitch was immediate and marked. I am removing full buckets of moist clay from a pond excavation, and prior to shimming I could not lift a full load in the bucket without the by-pass kicking in. It was very frustrating. Likewise, if the box blade was filled with wet clay and I had to lift it up and down to shake it out, I often found the 3-point hitch having some difficulties. Those troubles are completely gone on both counts. The loader can now break out and lift a full bucket of moist clay with no by-pass kicking in. So also the 3-point hitch. It is obvious why JD bumped up this pressure for the 3005. It is very helpful.
The performance of both the loader and 3-point hitch was immediate and marked. I am removing full buckets of moist clay from a pond excavation, and prior to shimming I could not lift a full load in the bucket without the by-pass kicking in. It was very frustrating. Likewise, if the box blade was filled with wet clay and I had to lift it up and down to shake it out, I often found the 3-point hitch having some difficulties. Those troubles are completely gone on both counts. The loader can now break out and lift a full bucket of moist clay with no by-pass kicking in. So also the 3-point hitch. It is obvious why JD bumped up this pressure for the 3005. It is very helpful.
Did you add one shim kit?
DWCox
Silver Member
Yes, just the one kit.
I probably should break down and put a guage on mine. I added one kit and it helped but not dramatically. Of course I don't do much loader work and as long as the 3pt lifts my box blade I'm OK. However, I just added my toothbar and 4 suitecase weights to my BB and plan to get 2 more suitecase weights so if I run out of lift I will need to put in some more shims.
