Aux Hydraulics for Dummies

[JimEd]

Landowner here with acreage to maintain looking to buy a 6-7 ton mini to complement a 100hp tractor. 50-75% of mini’s utility will be mowing pond banks and slopes not accessible with tractor mowers. I don’t anticipate a lot of digging. Only other experience I have in "heavy" equipment, besides the tractor, is running a brush mower on a rental 95hp CTL. I have none in excavators and the few rental outfits in my area that rent them do not rent mowers.

My question has to do with how the hydraulic pumps share the workload and if some manufacturers prioritize one part of the system over another. Example, can you run a rotary/flail head rated at, say, 16-25 gpm at the same time as moving on the tracks and slewing AND dipper/bucket movement without one or more of those actions suffering? I’ve watched some YT mowing videos where the machine (<4-5 ton) was squealing with the mower blade slowing noticeably when the machine was moving. Is this typical of excavators in general or just the lower hp machines? Do some machines have pumps dedicated to certain functions or larger pumps overall to minimize the hit? Machine literature gives you very little information other than flow and pressure. Any manufacturers you’d recommend for my application? Thanks in advance for any replies.

 

[KSSS]

There is a lot to unpack there. Some excavators have multiple pumps (my old IHI had four). Some have one. The way to maybe look at this like a pie. Every time you cut it, the pieces get smaller. You do one function and you get all of it. Multifunctioning the boom, stick, and bucket without moving the tracks is seldom a problem on a modern excavator. Running the aux. function and running the tracks and maybe using the stick in someway. Gives less flow to everything and you can for sure tell. When running a mowing attachment. I park the excavator in a spot and use the aux function exclusively with slow stick movement. It gives you the most flow and less hp diversion. There is a lot more that can be said to all of that, but hopefully that helps. Every OEM has their own way of dividing up the pie, some are better at it than others. Hp does matter, because the higher the hyd. hp, and the higher the PSI the better they cut/mulch as a general rule.

Another big concern (beyond GPM) on performance for running a mower/mulcher is PSI. My suggestion is get an excavator that has a separate aux line for the thumb and the aux. function. The PSI for the thumb has to be kept lower to prevent the thumb from bending under the force of the bucket. If you are tying into your thumb curcuit for your aux function you must run the attachment at the lower PSI setting. That kills productivity. On a machine that has a separate circuit you can keep the aux. PSI setting high without affecting the thumb PSI setting.

 

[92U 3406]

Most newer excavators have the ability to adjust pressure, flow and toggle 1 way/2 way flow in the monitors, which is nice for swapping attachments. Definitely want to set up the attachments initially by using a flowmeter and gauge because the only machines I've seen be ballpark close is Cat. Everyone else seems to be out to lunch with their numbers.

 

[JimEd]

There is a lot to unpack there. Some excavators have multiple pumps (my old IHI had four). Some have one. The way to maybe look at this like a pie. Every time you cut it, the pieces get smaller. You do one function and you get all of it. Multifunctioning the boom, stick, and bucket without moving the tracks is seldom a problem on a modern excavator. Running the aux. function and running the tracks and maybe using the stick in someway. Gives less flow to everything and you can for sure tell. When running a mowing attachment. I park the excavator in a spot and use the aux function exclusively with slow stick movement. It gives you the most flow and less hp diversion. There is a lot more that can be said to all of that, but hopefully that helps. Every OEM has their own way of dividing up the pie, some are better at it than others. Hp does matter, because the higher the hyd. hp, and the higher the PSI the better they cut/mulch as a general rule.

Another big concern (beyond GPM) on performance for running a mower/mulcher is PSI. My suggestion is get an excavator that has a separate aux line for the thumb and the aux. function. The PSI for the thumb has to be kept lower to prevent the thumb from bending under the force of the bucket. If you are tying into your thumb curcuit for your aux function you must run the attachment at the lower PSI setting. That kills productivity. On a machine that has a separate circuit you can keep the aux. PSI setting high without affecting the thumb PSI setting.

Thanks for the comprehensive reply! Definitely noting the separate aux circuit suggestion. I’ve been looking specifically at the Tak 250-2 and 260 for just that reason.

 

[JimEd]

Most newer excavators have the ability to adjust pressure, flow and toggle 1 way/2 way flow in the monitors, which is nice for swapping attachments. Definitely want to set up the attachments initially by using a flowmeter and gauge because the only machines I've seen be ballpark close is Cat. Everyone else seems to be out to lunch with their numbers.

I imagine the numbers are often wrong (inflated) on the high side.

 

[92U 3406]

I imagine the numbers are often wrong (inflated) on the high side.

Seen it both ways, usually everything was lower than what the monitor stated.

Always got calls blaming the attachments we sold/rented/repaired when they didn't work. 99/100 times the customer ate their words when we put the flowmeter on and saw their machine was out to lunch.

Sadly we even had to go out and set up a ton of machines the dealers set up wrong. Always fun arguing with the customer on that front.

 

[JimEd]

Makes sense that you need to know what your machine is putting out, but flow Meters/gauges aren't cheap. Wonder if there are outfits that rent them?

 

[92U 3406]

Probably cheaper to call someone out with one.

 

[KSSS]

Thanks for the comprehensive reply! Definitely noting the separate aux circuit suggestion. I’ve been looking specifically at the Tak 250-2 and 260 for just that reason.

I have the Taki 257 set up that way.

 

[uffex]

Good day
Weeds in drainage channels is a constant battle in some areas, this attachment explains some of the problems, sorry it's an attachment too heavy to dump here.
Kind regards
Uffex

GI Land drainage 1.pdf

drive.google.com

 

[JimEd]

Probably cheaper to call someone out with one.

Probably. But nowhere near as much fun.

 

[JimEd]

I have the Taki 257 set up that way.

Any thoughts on the Tak 250-2 v 260 for aux activity? They appear pretty close on specs on paper.

 

[KSSS]

Since your wanting to run a mower, I would go with the 260. It gives you a good bit more hp. I think for your purpose that would make it a better attachment platform. Also being heavier, it would make extending a mower attachment out more stable.

 

[f311fr1]

Look at a CAT 310 with aux pump for mulcher

 

[strykerakamack]

Ventrac

Makes a great machine for mowing slopes .Put the double wides on it
and its basically impossible to flip over