How much will JD790 TLB lift in bucket?

sixdogs · Sep 20, 2011

I have a JD 790 TLB and the backhoe is always hooked to the tractor hydraulic system. Does this diminish the weight capacity I can lift with the bucket? The other day I tried to lift an implement and the tractor was struggling more than I thought it should. Any idea of the lift capacity of the loader?
At the moment, I cannot find the loader owner's manual.

irwin · Sep 20, 2011

I think it's about 870 lbs.. I had a 770 which had the same specs just a little less hp.. I loved that little machine.... I did have to take smaller bites of gravel. I got use to it, but it was one of the reasons I upgraded tractors was loader lift capacity.. the other reason was backhoe digging depth and strength..

Still I shouda kept the 770, there are times when something smaller would be better.

Muxster · Sep 20, 2011

The backhoe should not change the capacity of the loader. The hoe may use the same pump but typically you will not be moving the hoe and loader simultaneously. Even if they were used at the same time all it should do is slow down the rate of movement. The loader capacity is limited by the relief valve setting which stock is (i think) around 2100 lbs which translates to about 740 lbs in the bucket. In stock configuration the lift capacity of the 790 is weak. I couldn't lift a full bucket of wet topsoil with mine. A lot of folks with 790s shim the relief valve (as did I) to make it open at a higher pressure. Now I can lift a full bucket of what ever I put in it without any problem.

hizoot · Sep 20, 2011

Just curious...Could you explain how to arrive at loader lift capacity via pressure setting? I wonder where I would need to shim my 2520 for a little extra oompph.
Randy

RoyJackson · Sep 21, 2011

hizoot said:
Just curious...Could you explain how to arrive at loader lift capacity via pressure setting? I wonder where I would need to shim my 2520 for a little extra oompph.
Randy

The 790s were shimmed at the pressure relief valve (port is under the operator's seat). I did it on mine several years ago.
The shim kit cost a couple bucks (less then $10), but that doesn't mean they're even available for your 2520.
You'll want a service manual (or at least pages from the hydraulic section)to do this right. Another way to get a picture of the components (to show you where the shims need to be installed) is JD Parts. You'll need to register for JD Parts, BTW.
Before you do this, do a bit of research on TBN (a search in the Deere Owning/Operating forum would be a good starting place) to see what all is involved and potential pitfalls.

Muxster · Sep 21, 2011

hizoot said:
Just curious...Could you explain how to arrive at loader lift capacity via pressure setting? I wonder where I would need to shim my 2520 for a little extra oompph.
Randy

The force the hydraulic cylinders exert is a function of the system pressure and the surface area of the ram. For example if the system pressure is 2000 psi and the surface area of the ram head is 2 square inches, the force would be 1000 lbs. Then there is the mechanical advantage of the lever arms of the loader.

Every hydraulic system must have a relief valve in it. The 2520 pressure may be closer to the system design maximum pressure (rating of the hoses and cylinders, etc.). You should research that a little more before modding the 2520 relief valve. There may be a little more room... I don't know. The 790 relief in stock configuration is way low in comparison so there was room to raise the lift pressure.