We bought a new bobcat 337 and a 40" samurai flail mower from USMowers. We told the bobcat dealer over and over that the aux hyd must have priority over the rest of the system when the aux is in use. That way the mower always has full power. Everything should go slower to keep the mower at full power. USMower told them the same thing. The bobcat dealer said it would be no problem. We didn't get it in writing. Upon delivery we found that the aux hyd is the first to derate whenever anything else on the machine is used. We made them take the machine back, twice. We got the Alaska regional manager involved, he is just another salesman and a complete waste of fresh air. Finally they said it can't be done. We have been running the machine for 2 summers and unless you have the touch and great patience cutting thick brush is tough. The mower is awesome and just chews up and spits out 2" brush in little pieces. But you have to swing the house very very slow to keep the mower running anything close to full power. When you swing the house or move the hoe too fast or more than a few inches at a time the mower looses enough power that the blades start to bounce and not cut nearly as efficient. You can actually see the mower slow down when you point so you can watch it and swing the house. The mower is run off the main aux that usually powers the thumb. To operate the mower, turn on the aux and pull the trigger on the right control once. Pull it again to shut it off. I added the secondary aux hyd kit so we could run the thumb when the mower is attached. I am ready to try replumbing the hydraulics myself and wonder if anybody here is familiar with this machine.
I have heard of people having trouble running flail cutting heads on hi-flow skid steers let alone a mini!! I have wondered myself how these would run on mini's as the movies that I have seen of them seem to show them working well even when swinging the house quite fast and this was on a 1.5 ton machine. As for replumbing the machine I would be wary of affecting the load sensing system or similar technology that the machine may have.
Is your machine fitted with a hammer circuit? If so run your mower on this circuit with the return oil from the mower going directly to the hydraulic tank (not into the spool blocks). Bobcats in the UK have dual flow hammer circuits (the circuit can run a auger in either direction using dual flow OR on single flow can run a hammer or mower. If the above does not work you could combine the hammer and aux circuits, BUT you will need to talk with a good hydraulic shop to modify the machine correctly. If the machine is still warranty this idea may be a problem Regards
A fellow UK based member!! Welcome to the forum. I believe the machine is pretty new so as you say the warranty will be a problem.
The machine is out of warranty so no issues there. The hammer setup sounds interesting. I was thinking I'd pull the feed prior to the spool, tee the line with some sort of priority valve and electric actuator. Return straight to the tank. I would return the thumb to its orignal circuit and probably ditch the secondary aux system we added.
Reference your mower problems. I think running the mower via a hammer circuit will solve your problem, we have customers who run 48 inch mowers with 5 tonne excavators (Takeuchi or Neuson) without too many problems. I would suggest that you contact your Bobcat dealer and get a price for a hammer pipe and control kit for your 337. If they are any good as a dealer they ought to sell you the kit at cost if you pay to have it fitted. Next, when the kit has been fitted get them to run a flow-meter test on the hammer circuit, the result will confirm that this circuit will supply enough oil flow at the correct pressure to run your mower. Your mower supplier can tell you what oil-flow and pressure you need to run the mower. Use large bore hoses (at least 3/4) to and from the mower, and if you are using quick release hose fittings make sure they are high quality flat face type fittings. I'am sure you have tried some of these fixs already. Regards
Talking about aux hydraulics, I am considering whether I can fit the auger head that attaches to the dingo onto the Kubota KX41-3. The problem is not so much the actual engineering, I will try and get an dingo quick attach plate (depending on cost) and modify it so it fits on the ex, that way I can use the auger on both machines. The problem I see is flow rate, the dingo is rated at 47L/min and the Kub is rated at 27.7L/min. There does not seem to be much difference in pressure the dingo is 3400psi and the KX is rated at 3132psi. The rating of the dingo I assume is at flat out with full flow to the aux circuit and it runs the auger pretty well without having to give it everything it's got. Those familiar with a K9-4 dingo will know that there are various ways to control the flow, for maximum pressure and flow to the aux circuit you put the machine in bottom gear and push the flow control lever all the way forward, which I don't know whether it affects pressure much but it improves the flow and thus the speed of the auger. So am I correct in understanding that flow rate is what affects the speed of the implement you are trying to run and pressure determines the amount of power it has? Which means the KX should run the auger head pretty well but perhaps not as fast or with quite the same power as the dingo can when flat out. Going back to the original question in this thread, yes modern excavators do have priority systems in place and the aux circuit is designed to be used in stationary mode, such as for using rockbreakers and earth augers. As an example going back to the dingo, when I use the auger in full flow mode, nothing else on the machine will work and I have to 'throttle' back the flow adjuster to half in order to lower/raise the arm or move the wheels. Also when the dingo is in full power to the wheels mode the aux circuit does nothing. I do not know if it is possible to fit such a control to your Bob but if you could then you have control over the flow and can adjust it so that you find a balance between the mower being able to get through the tough stuff and the ex being able to move. My advice is to skip the local sales people and either talk to the factory or find an expert on hydraulics, who knows the hydraulic system on your machine.
Is there a minimum flow rate for the auger that you have?? As you say the pressure is there but whether 27 litres per min is enough to get the auger turning effectively will depend on its flow range. e.g. my hydraulic breaker for my K008-3 has a flow range of 14-30 litres per minute so it would run on the K008-3 and the KX41-3 (providing I changed the top mounting plate!!)
According to the dingo website http://www.dingo.com.au/post_hole_digger_spec.php it is rated at 32L/min, which is not too far off the 27.7L/min the KX is rated at. So that may well mean that the auger turns a bit slower on the KX but that is not a drama, as the purpose is to use the auger in spots where the dingo can't get at and thus extending my capabilities without spending a fortune on more gear. For mass boring of holes in a semi flat environment, the dingo is still better.
Try hooking the auger up hydraulically to the KX41-3 while having the dingo actually attached to the auger as you usually would and see: 1) if the auger will turn at all 2) if the auger will drill into the ground adequately This way you will get a good idea as to whether it will work without having to carry out any major alterations e.t.c