790 loader

[godaddy]

I just finished rebuilding the front end (4X4) on my tractor at a cost cost of $1350 just 4 parts. The guy that pressed my pinion bearings on for me said that a friend of his that works at a skid steer place as a tech told him about some shimes to put in the hydrolic valve under the seat to give the loader more lifting power. He gave me the part # and showed me the shimes that were left over. He said it made a pretty sig. difference in the loaders lifting cap. I have not had a chance to look at my shop manual to see exactly were these shimes go. I'm just concerned about the extra pressure it would put on the cylinders. Has anyone done or heard of this? Oh yea, not hard at all to do the front end on this thing if u have a press and dial indacator for the backlash.

 

[kennyd]

This is/was a very popular modification to the 790's years ago...Here is just one of many threads to read:

Increasing Hydraulic pressure on Deere 790 - TractorByNet.com

 

[godaddy]

Thanks kennyd! Just what I was needing.

 

[RoyJackson]

The attached .pdf instructs on shimming the hydraulic relief valve.
As Kennyd wrote, quite a few 790s were modified like this 4 or 5 years ago.
It's going to improve things somewhat, but be realistic in your expectations.

I added one set of shims and experienced no problems. Don't go overboard on shimming the relief valve if you want long term durability of your hydraulics system.

BTW, the instructions caution about losing any components when removing the relief valve cap. If at all possible, do this on a smooth cement floor and sweep the floor clean before removing the cap.

 

[kennyd]

Just to add to what Roy wrote, You MUST have a gauge to check the before/after pressures so you don't damage anything. One can be made up for about $30 or so.

Here is a picture of mine:

 

[spruce Deere]

I had the dealer do mine, pretty much days after i bought the 790.

2350 psi on the gauge and I helped mine out quite a bit.

Before the shim job I could not lift a full 61 inch bucket of dirt with the 300 loader.

After the shim job, I can now lift a 1000 lb. bag of fertilizer high enough to get it off my trailer and into the shed.

3 years into it and still no adverse effects due to the 'shim trick' Well, other than I'm thinking little bit more would not hurt....... but thats how busted, bent things start showing up

 

[kebo]

Here's a picture of the gauge I bought from a local hydraulic shop. It was $19, plus a few dollars for the fitting on it. Get one with a range of 0-3000psi if you can find it, that will give you the best resolution & accuracy.

 

[godaddy]

Kebo, did u get the fitting @ the jd place? Tractor supply did not have any to fit. Also, have u done the shimes to your 790?

 

[kebo]

Kebo, did u get the fitting @ the jd place? Tractor supply did not have any to fit. Also, have u done the shimes to your 790?

Nope, got the fitting at the same hydraulic shop that sold me the gauge. Can't help you much with that, I don't know the brand or part number of that fitting.

I have added the shims to my tractor, which is why I bought the gauge. I think I put in one complete shim kit and just one very thin shim of a second kit to bring the pressure up to exactly 2500psi. Works great now, it's a very cheap improvement that gives you a sizable increase in capability.

 

[godaddy]

Well that's ok! I had to oder the male end today from the jd place when I picked up the shimes. Will make the gauge and then add the shimes. I live in Anderson myself. Really been getting rain lately. Things really greening up right now. Hope it does'nt go to dry this summer.