Backhoe Jinma LW-6

[Nuno]

Just found this picture, this is the setup I am going for, though now I'm realising that the pump that came with most LW6s are E10,

will this mean that you now understand what i try to explain in my posting before?

 

[RonMar]

If all else fails, them I'm going to plumb the backhoe into the tractors hydraulics, what do you all reckon about that? good or bad idea?

Providing the tractor hydraulic pump is large enough to meet the needs of the BH, The only drawback with directly plumbing the BH into the tractor system is the low volume of hydraulic fluid in the tractor's system. The duty cycle for most tractor hydraulics is pretty low, with typically just sporadic use.(scoop up a load with the loader, drive someplace and dump it. Raise the 3PH, a little while later lower it again, ECT). The hydraulic fluid is always circulating under low pressue but is only occasionally tasked with any work. Backhoes can really heat up the fluid, as they are constantly performing work when in use(dig, pull, rip, lift repeat). Work requires hydraulic pressure(and flow). The restriction in flow that generates the pressure to move the BH causes heat in the fluid. When I am working mine hard, the 7 gallons of fluid in my BH can heat up pretty quickly.

If I were going to use the tractor hydraulics to power the BH, I would incorporate the BH resovoir into the circuit to increase the fluid volume when the BH is attached. This has to be done correctly and requires some minor modifications to the BH resovoir to keep from loosing fluid there, or overflowing the tractor resovoir. If plummed properly it should work fine, and greatly increase the system volume when operating the BH, as well as add the additional tank surface area to help provide some cooling to the fluid.

 

[erj]

Quote:
Originally Posted by erj
Does this mean that the pump that you showed back in post 20 does not simply bolt onto the spot where you removed the plate?
RonJ

Correct Ron, it's a bigger bracket that also uses 4 bolts to with the 6 splined lower PTO shaft as centre.

First off, I apologize the angle of the pump that you showed in post 20 led me (and I think others) to believe that you had the correct pump for mounting to the PTO Auxiliary shaft which is located above the PTO multi-splined shaft.

Is there no way that you can get the people who provided the incorrect pump to get you the correct one?

One of the concerns that I would have in using the pump that you have is that we do not know the internals of it and what will be the actual result whether you modify it to work on either the PTO or PTO Auxiliary shafts.

Many of us have the LW06, HW03, LW03 backhoes and know that the correct pump on that PTO Aux shaft will work the backhoe.

Here are pictures of the pump that you should have.

RonJ

 

[JoelD]

Speed has very little to do with pressure, in theory your pump will put out the same PSI at 500 rpm as it would at 5000 rpm, just less volume.

Speed is volume, relief valve governs psi.

Joel

 

[trelli]

Yes I agree in theory that the pump should put out the same psi irrespective of rpm, but that would only be in the case if there was no backflow through the pump and the tolerances between the gears and the housing were so tight that it allowed this. The deadheading experiment I did proved that these pumps cannot hold pressure unless they spin, if the pump ran and then suddenly stopped, the pressure would cause the oil to eventually flow back through the pump and to a state of zero pressure.

 

[Bob Rooks]

A gear type hydraulic pump can also be used as a hydraulic motor. The pumps themselves are not designed to "hold" pressure, that's what the spool valves are for. You should never, in any instance, have a situation where oil would back flow through a pump.