mountain_man
Gold Member
That's exactly what I was lookin' for. To me, the 70 loader seemed a little underpowered considering the "heft" of the frame, cylinders and the tractor. I'll give it a try. Thanks mucho!
790 HP Reduction By John Deere
- Thread starter Mrwurm
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scottbrrtt72
Bronze Member
Mark,
I recently purchased a log skidder attachment for my 3-point hitch. I was extremely disappointed when I tried lifting a log with my 790 and it wouldn’t budge. The specs on the 790 3-point hitch is 815 lbs. With the additional shims do you have an idea of what the 3-point hitch can lift at 2500 PSI? I would be very interested in finding that out. I also have the #7 backhoe with my machine. Would that added PSI affect the backhoe at all? I will try calling the dealer and get there suggestions on making this change. My machine is a 2001, so I am not worried about a warranty issue. When my 790 was at the dealer for service I had them test the lift capacity of the loader. It came in at 860lbs, which is above the specs for the 70 loader. I believe this was from the ground to a certain height. I know after a certain height you start loosing lift capacity. I started thinking I would have to buy a bigger machine, 4010 series. I really don’t want to do that since my 790 is paid off. Any information would be great.
I recently purchased a log skidder attachment for my 3-point hitch. I was extremely disappointed when I tried lifting a log with my 790 and it wouldn’t budge. The specs on the 790 3-point hitch is 815 lbs. With the additional shims do you have an idea of what the 3-point hitch can lift at 2500 PSI? I would be very interested in finding that out. I also have the #7 backhoe with my machine. Would that added PSI affect the backhoe at all? I will try calling the dealer and get there suggestions on making this change. My machine is a 2001, so I am not worried about a warranty issue. When my 790 was at the dealer for service I had them test the lift capacity of the loader. It came in at 860lbs, which is above the specs for the 70 loader. I believe this was from the ground to a certain height. I know after a certain height you start loosing lift capacity. I started thinking I would have to buy a bigger machine, 4010 series. I really don’t want to do that since my 790 is paid off. Any information would be great.
F350Lawman
Gold Member
I have added the shim pack.
Well this is justa guess, but if our factory psi was 2100lbs and now it is 2500lbs., I would think it might be about a 20% increase in lift capacity? So maybe it is about 1000lbs at the 3 point. That would actually be 1000lbs -24" behind the ball ends.
I know my tractor really did not lift the front end by pushing the FEL down unless I used the curl function, now it lifts easy. I also now lift a rock to full height that I could only lift a couple if inches before the "modification".
Not really scientific, but capacity has increased with no ill effects thus far with the addition of one pack of shims.
1000lbs of 3 point hitch lift should skid a pretty BIG log, after all aren't you just lifting the end? Seems like a log much bigger than that could easily get away from you on any type of hill with such a light tractor.
With the modification I think you will find the tractor will lift anything that yuo would want to SAFELY lift and transport with a 790.
Not that I wasn't before but I am very pleased with the machine.
Well this is justa guess, but if our factory psi was 2100lbs and now it is 2500lbs., I would think it might be about a 20% increase in lift capacity? So maybe it is about 1000lbs at the 3 point. That would actually be 1000lbs -24" behind the ball ends.
I know my tractor really did not lift the front end by pushing the FEL down unless I used the curl function, now it lifts easy. I also now lift a rock to full height that I could only lift a couple if inches before the "modification".
Not really scientific, but capacity has increased with no ill effects thus far with the addition of one pack of shims.
1000lbs of 3 point hitch lift should skid a pretty BIG log, after all aren't you just lifting the end? Seems like a log much bigger than that could easily get away from you on any type of hill with such a light tractor.
With the modification I think you will find the tractor will lift anything that yuo would want to SAFELY lift and transport with a 790.
Not that I wasn't before but I am very pleased with the machine.
HalseyGreen
Silver Member
I was looking at my parts and service manual last night, from the parts manual there appears to be a seperate relief valve for the three point, and it listed a different part number for the shim pack for it. The three point is adjusted by shims under the cap to the left of the system relief valve. Not sure how the system valve reflects on the three point valve.
F350Lawman
Gold Member
I was looking at my parts and service manual last night, from the parts manual there appears to be a seperate relief valve for the three point(part #5), and it listed a different part number for the shim pack for it. The three point is adjusted by shims under the cap to the left of the system relief valve(#6). Not sure how the system valve reflects on the three point valve.
I see what you mean, the 3pt relief valve is the next biggest cap and is to the left of the system relief valve cap. from the drawing the shims are as easy to add as the system relief valve.
A couple of questions? Does the system relief valve pressure contol the entire system? Adding shims to the system relief valve as we have COULD still have raised the 3pt capacity IF the 3pt valve is set from the factory at a higher setting so that the sytem valve trips first. It is possible that JD has the system valve set as the limiting factor at 2100lbs and thet the 3pt is at a different, higher setting as a backup in case of a clog or defect etc??
I don't think any of us have tested the 3pt lift after the modification (no need for most of us). My gains were measured ny FEL lift. I have nothing thta would warrant adding the 3pt shims IF that were needed but the procedure would be equally simple and the part is $2.
I still have a feeling the system valve has an effect on the 3pt and thta the 3pt valve COULD be an additional safety built in to the system. If the 3pt defaults at he same or lower pressure than I am dead wrong and you need to add shims (parts # 7 &8 )right to the 3pt.
We could use the original posters help?
All I know is my tractor lifts itsef to full height easily with the FEL w/o using curl now. It would not do that before. My 3pt capacity is still unknown however.
I see what you mean, the 3pt relief valve is the next biggest cap and is to the left of the system relief valve cap. from the drawing the shims are as easy to add as the system relief valve.
A couple of questions? Does the system relief valve pressure contol the entire system? Adding shims to the system relief valve as we have COULD still have raised the 3pt capacity IF the 3pt valve is set from the factory at a higher setting so that the sytem valve trips first. It is possible that JD has the system valve set as the limiting factor at 2100lbs and thet the 3pt is at a different, higher setting as a backup in case of a clog or defect etc??
I don't think any of us have tested the 3pt lift after the modification (no need for most of us). My gains were measured ny FEL lift. I have nothing thta would warrant adding the 3pt shims IF that were needed but the procedure would be equally simple and the part is $2.
I still have a feeling the system valve has an effect on the 3pt and thta the 3pt valve COULD be an additional safety built in to the system. If the 3pt defaults at he same or lower pressure than I am dead wrong and you need to add shims (parts # 7 &8 )right to the 3pt.
We could use the original posters help?
All I know is my tractor lifts itsef to full height easily with the FEL w/o using curl now. It would not do that before. My 3pt capacity is still unknown however.
Attachments
I was told by the service department at my JD dealer that adding the shims would increase the relief pressure for the whole system, including the 3PH. I know the factory specs for the 3PH are somewhat low compared to other brands, but I have no complaints about the lift capacity of mine. It will lift a very large disk (actually too big to be using w/this tractor) as well as other heavy items. I was plowing w/it once and the plow caught on a root. I lifted the 3PH and it pulled down so much that the tractor gained extra traction. It would've killed the tractor had I not hit the clutch.....it has plenty of power.
The loader is a different story. I have the 419 loader which has even lower specs than the old 70 loader did. As I said before, two packs of shims made a big difference....then I looked at a guage and got scared. I took one pack out and that left the PSI at about 2500. The bucket will now lift what will fit in it.....
The loader is a different story. I have the 419 loader which has even lower specs than the old 70 loader did. As I said before, two packs of shims made a big difference....then I looked at a guage and got scared. I took one pack out and that left the PSI at about 2500. The bucket will now lift what will fit in it.....
nickgalyon
New member
- Joined
- Sep 24, 2004
- Messages
- 7
Thanks for posting the parts diagram. Several of the previously mentioned small parts got away as I pulled off the cap. The diagram and a magnet resolved that issue.
I ordered 2 packs of shims. The dealer only sent 1. He cautioned me about damage to the front wheel drive system from excessive loads in the bucket.
I installed the shims (4) that came in the package. Prior to installation the loader would not lift the front of the tractor off the ground, now it will.
I ordered 2 packs of shims. The dealer only sent 1. He cautioned me about damage to the front wheel drive system from excessive loads in the bucket.
I installed the shims (4) that came in the package. Prior to installation the loader would not lift the front of the tractor off the ground, now it will.