JD 790 300 loader

   / JD 790 300 loader #1  

adamls78

New member
Joined
Sep 23, 2008
Messages
10
Location
east Georgia
Tractor
05' Johndeere 790
I just wanted to know if anybody thinks the 300 loader is on the weak side or if it is just mine.
 
   / JD 790 300 loader #2  
You can increase the maximum hydraulic pressure on the 790 by putting in a shim kit.
 
   / JD 790 300 loader
  • Thread Starter
#3  
Put a shim kit where?
 
   / JD 790 300 loader #5  
Put a shim kit where?

On the relief valve...This has been discussed a lot in the forum-it seems the 790's have very a very low pressure setting from the factory. You will NEED a gauge setup to adjust the pressure. It's not the loader's fault:D
 
   / JD 790 300 loader
  • Thread Starter
#6  
Where do you get the kit from and has anybody had problems with hoses blown off after the kit was installed
 
   / JD 790 300 loader #7  
JD -- AM875169 SHIM ***'Y, RELIEF 2.68 2.68 Stock.

I've had no problems. I put all the shims in the kit in. I think some have put multiple kits in. Certainly if I was going with more than one kit I would check the pressure when the relief valve kicks in.
 
   / JD 790 300 loader #8  
That part # is a bag of shims. Any JD dealer should be able to order it for you. Definitely the best 2$ modification for a 790. While your there, get the o-ring for the pressure regulator. I didn't check the link, but I assume it's the one with pictures and instructions. They recommend the o-rings to be replaced, and sure enough when I dis-assembled mine, the o-ring broke and turned the 20 minute job into a 2-day job, cause I had to go get parts.

You won't be popping stumps out of the ground, but after the kit is in you'll be able to easily lift a bucket full of wet GA clay, I mean dirt!
 
   / JD 790 300 loader #9  
Ordered 2 shim packs for my 790/300 yesterday. Shimming the relief valve to 2500psi seems to be what most 790 owners have done on tbn. I could be wrong but I think it would be safe to shim the pressure up to 2600-2700psi. The 3005 Hydraulic System has a working pressure of 2422-2698 psi. Both tractors have the same hydraulic pump, same part number. I believe the slightly larger flow rate of the 3005 (10.3 gpm) over the 790 (9.6 gpm) is due because of the higher pressure. I have a gauge and quick coupler setup to accurately adjust the pressure so we will see.:)

But... like I said before, I could be wrong.:eek:
 
   / JD 790 300 loader #10  
Ordered 2 shim packs for my 790/300 yesterday. Shimming the relief valve to 2500psi seems to be what most 790 owners have done on tbn. I could be wrong but I think it would be safe to shim the pressure up to 2600-2700psi. The 3005 Hydraulic System has a working pressure of 2422-2698 psi. Both tractors have the same hydraulic pump, same part number. I believe the slightly larger flow rate of the 3005 (10.3 gpm) over the 790 (9.6 gpm) is due because of the higher pressure. I have a gauge and quick coupler setup to accurately adjust the pressure so we will see.:)

But... like I said before, I could be wrong.:eek:

The online specs I see for the 3005 are:

Hydraulics
Type Open Center
Pump Rated Output, gpm (L/min.) 9.4 (36.4)
Steering 4.2 (15.9)
Implement 5.4 (20.5)
Pump Type Single gear (Manual steering models); Dual gear (Power steering models)
Maximum Operating Pressure (PSI) 2050
Draft Control Type Position control
Remote Control Valves Available 2

All the same as the 790. I don't think anything was changed except the name. At 2500 I would be worried about my pump and hoses and most of all being able to lift more than the tractor can handle. Just my opinion.
 
   / JD 790 300 loader #11  
The online specs I see for the 3005 are:

Hydraulics
Type Open Center
Pump Rated Output, gpm (L/min.) 9.4 (36.4)
Steering 4.2 (15.9)
Implement 5.4 (20.5)
Pump Type Single gear (Manual steering models); Dual gear (Power steering models)
Maximum Operating Pressure (PSI) 2050
Draft Control Type Position control
Remote Control Valves Available 2



That is weird.:confused: Last time I looked at the 3005 specks online it was what I quoted earlier. The online 3005 owners manual shows the higher hydraulic working pressure in the Specifications.;)



OMLVU19591_J7
 
   / JD 790 300 loader #12  
That is weird. I had never looked at the 3005 manual just the online specs and thought that they hadn't changed anything. I hadn't realized that they had changed the pump and the relief valve settings. I wonder which numbers are correct? Has anyone measured the maximum pressure on a 3005. Do anyone of the JD dealers know? If the rest of the tractor and the 300 loader handles it I might put in another shim kit. My TNT hoses are rated to 3000 psi.
 
   / JD 790 300 loader #13  
It would be good to know what the 3005s hyd. pressure really is. I should have stated earlier that I do not plan on installing 2 complete sets of shims. just enough to get to 2600psi. Here is a 5 page thread on the subject. It is dated back to the 419 loader, but still great thread

Well... wont let me put a link to a a different Discussion Board. sorry.:rolleyes:
 
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   / JD 790 300 loader
  • Thread Starter
#14  
I put the whole shim kit in and I'm goin tell ya'll what , it made a big difference. Before the tractor would barely pick the front tire off the ground, now it goes right on up at idle. And I just had to try out something heavy so I put up the back of my Chevy 1500 by the hitch. Its funny how a few mm. of shims can change all that. Thanks for the advise.
 
   / JD 790 300 loader #15  
JD -- AM875169 SHIM ***'Y, RELIEF 2.68 2.68 Stock.

Is there supposed to be more numbers where the *** are?
I'd be interested in putting one of these kits in my 790. Thanks!
 
   / JD 790 300 loader #16  
Is there supposed to be more numbers where the *** are?
I'd be interested in putting one of these kits in my 790. Thanks!

I just cut and pasted out of my parts CD so I don't know what the *'s are for. The number is AM875169.
 
   / JD 790 300 loader #17  
I just cut and pasted out of my parts CD so I don't know what the *'s are for. The number is AM875169.

My guess is the *'s are to show not all the text is there. Probably should say.

JD -- AM875169 SHIM ASSEMBLY, RELIEF $2.68 $2.68 Stock.
 
   / JD 790 300 loader #18  
Mech is right. I still had the bag that the 4 shims of different thickness came in. here is pic of bag w/number.
 
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   / JD 790 300 loader #19  
Have it written down now. Thank you.
 
   / JD 790 300 loader #20  
Mech is right. I still had the bag that the 4 shims of different thickness came in. here is pic of bag w/number.

Hmmmm.....I ordered a shim kit from the part number in an earlier post a month or so ago....and my package included only 2 shims (at least thats what I remember seeing in the package...possibly they are stuck together??).

I am waiting for a hydraulic coupler to arrive...at which point I plan to assemble a wet gauge for before and after testing. I'd swear there is only two shims in the pack I got (each of 'em about 3/8" diameter by .050 thick??). I need to check my package again for the shim count (its in my tractor a few miles away).

Are all of you guys getting 4 shims in a package? :confused:
 

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