Skid Steer backhoe hydraulics

mike@watervillegenealogy · Sep 7, 2008

I have read many of the hydraulic threads and so I have a general idea of what to do, but I am still confused as to size and single or 2 stage pump for this project:
I have acquired a Davis Mfg 100d backhoe attachment that was originally for a skid steer, but someone put on the hardware to make it a 3 pt attachment. It is too heavy for my B3030 Kubota without a sub frame and I do not use it enough to want a 3 pt mount. My plan is to make a short trailer and use a pto pump. I have hooked it up to the tractor hydraulics on a 50hp Kubota and while there is plenty of power it is ridiculously slow, that's why I want a pto pump. Bottom line I think I need a 2 stage pump delivering 10 to 12 gpm, but I am unclear on the psi requirements.

Any help would be appreciated.
Mike

john_bud · Sep 8, 2008

Mike, you don't need a two stage pump. Those are commonly used on wood splitters, not tractor pto's.

Find out what volume you need and what psi. Get a single stage gear pump designed for a pto. You probably want 12-15 gpm at full 540 pto rpm and 2000-2500 psi. Surplus center (site sponsor) should have what you want in stock. Ideally, you want asump volume of gallon of oil for each gpm. Practically, you can get by with 1/2 that, but the oil will heat up more and quicker.

You will also want to add in a pressure relief valve. Yeah, there should be one in the hoe, but....

Here is a bit of opinion. The hoe on a cart will be not very useful. Why? every pound of digging force is countered by a pound of weight. Tractors have a lot of weight, trailers not so much. Your going to be raising the hoe up into the air more than you will be digging. Unless you make the trailer weight = to the hoe digging force....

jb

mike@watervillegenealogy · Sep 8, 2008

Thanks for the info. Long story on the major reason for using a cart, but I tried the hoe on a small tractor once and broke the tractor. It is just a little too mean for a compact tractor. Since the conversion from skid steer is home made it doesn't lend itself well to mating with a store bought sub-frame. Using a cart means you almost always have to curl the buck back in a manner to pull on the tractor instead of pulling up on the ground. Not the best but the price is right. For bigger jobs I have access to a compact Kubota hoe, I just want o use this freebie for quick real small jobs without having to travel to borrow the other.

Mike