Question about hydraulics performance on different excavators.

[Jchonline]

My M59 with multiple pumps had the worst hydraulics I’ve ever had on a machine.

Yes I will say the M62 backhoe was very different than the KX040. Not nearly as smooth or responsive…but I dont expect it to be. It did have 2 different pumps.

I also looked at some others On the comparison chart below. Crazy enough the KX018-4 has 4 pumps! That is a really small machine!

https://www.kubotausa.com/docs/default-source/product-comparison-pdfs/k-competitive.pdf?sfvrsn=20c40b7c_4

 

[Hersheyfarm]

My M59 with multiple pumps had the worst hydraulics I’ve ever had on a machine.

Yes, my m59 lost both pumps at 75hr. Replaced under warranty. Good power in backhoe but slooow. loader was good but too weak for the big bucket. My m62 was better, but it was still slow digging compared to the 040.

 

[Hersheyfarm]

Yes I will say the M62 backhoe was very different than the KX040. Not nearly as smooth or responsive…but I dont expect it to be. It did have 2 different pumps.

I also looked at some others On the comparison chart below. Crazy enough the KX018-4 has 4 pumps! That is a really small machine!

https://www.kubotausa.com/docs/default-source/product-comparison-pdfs/k-competitive.pdf?sfvrsn=20c40b7c_4

I was just about to mention that..lol
seems there are reasons for multiple pumps on some, probably depends on hp and volume of cylinders..
I will say I absolutely no complaints with the speed and smoothness of the kx040, it has pretty good power too. The hydraulic system is not comparable to the m59/m62. No contest. Maybe its like scotty said open vs closed, cause something is different. M62 has more power and 31gpm between 2 pumps vs the the kx040 single pump and 24gpm, the kx is in way higher league as far as the quality of hydraulics.

 

[rScotty]

Regarding 3 pumps.... I don't know. I don't see three pumps listed on other mini-excavators....but our M59 tractor has three pumps and that's not common either. Maybe it's worth a trip to a parts book to make sure.

On the current Kubota Brochure for the U48 online (below) it says it has a 1 pump load sensing system with a pressure accumulator. That sure sounds like a closed hydraulic system with a variable displacement pump. Maybe that is one pump with 3 diffenent settings? Honest mistake or advertising?

Advertising departments spend a lot of time figuring out special ways to stretch things that allows them to to publish exaggerated numbers. Or even confusing ones. That's fair, their goal isn't to make honest comparisons, it's to make their own product look good. The truth doesn't really enter into it. I don't think any of this comes as a surprise to the old hands here on TBN. For us, it is always fun to compare things and the advertising department people know that as well. So we compare for fun, but I think nobody really believes those numbers are significantly different. Or real.

Lets see... how about system pressure? Well, hardly anyone makes their own hydraulic fittings. Even the really big companies leave that to specialists and there is a sweet supply spot at 3000 psi give or take 10% for error. So regardless of what they say, unless the price is really, really higher than the competition then that pressure is what everyone is using.
For advertising, the 3000 psi is static pressure of course, so the moment the fluid begins to move the pressure drops. Now using lhigher dollar hoses and and expensive fittings is where that dynamic pressure drop can be reduced a little. Or vice versa. Nobody measures or advertises that pressure drop, but you can bet they know about it.

The same type of reasoning applies for pins and arms made of steel and riding on bronze bushings. They are all very much the same since designers all now use the same hydraulic fittings, the same finite element design programs for all the geometry, and the same steel alloys.... and even the same Art Int. programs to optimise the variables.
There are few if any secrets there. It's a mature industry.

About the only thing that is left is aesthetics, design, & assembly for reliability. "Good" does cost more to build.

 

[Hersheyfarm]

Scotty, kubota is proving to be bad with published information. They get stuff wrong all the time. here’s their competitive comparison pdf you can click on, on the same page where you got that from.

It clearly says 3 pumps. Plus they got the breakout force wrong. Of all places to get something wrong…

 

[rScotty]

I was just about to mention that..lol
seems there are reasons for multiple pumps on some, probably depends on hp and volume of cylinders..
I will say I absolutely no complaints with the speed and smoothness of the kx040, it has pretty good power too. The hydraulic system is not comparable to the m59/m62. No contest. Maybe its like scotty said open vs closed, cause something is different. M62 has more power and 31gpm between 2 pumps vs the the kx040 single pump and 24gpm, the kx is in way higher league as far as the quality of hydraulics.

Ok. There's an example we can use to check the numbers from the advertising dept....and in this case they are going to look very good for Kubota.
HP = (flow (gal/min) * pressure (psi) all divided by 1716 to make the units come out right.

Turn it around with some basic algebra and we find that if we are looking at 24 gal/minute constant flow, the max pressure we can make with a 40 HP Yanmar motor runnng flat out is just under 3000 psi. That's close enough to call it a bullseye in my book.
Anyone saying they are getting higher flow rates with that same engine is exaggerating. Or whatever you want to call it.

BTW, our M59 has some of the sweetest, fast, accurate. and powerful hydraulics one could ever want. They just don't come better and most are not nearly so good. It will lift huge rocks and move a quarter inch controllably when stacking rock walls.
Was that just Luck? It was one of the first M59s built.
rScotty

 

[4570Man]

BTW, our M59 has some of the sweetest, fast, accurate. and powerful hydraulics one could ever want. They just don't come better and most are not nearly so good. It will lift huge rocks and move a quarter inch controllably when stacking rock walls.
Was that just Luck? It was one of the first M59s built.
rScotty

I think if you ran an excavator with joystick controls for an hour you’d quickly become disappointed with the M59 hydraulic. It wasn’t so much the precision of the backhoe that was in question as much as operator comfort and the speed of the hydraulics. I could take at least 2 scoops probably 3 on my excavator to every one the M59 will do. And the M59 front loader was less disappointing than the backhoe but the cable drive loader control wasn’t as good as it could have been. I know a backhoe will never equal a skid loader and mini x no matter how good it is but Kubota left room for improvement on that so called industrial machine. That’s an excellent tool when compared to a tractor backhoe, and I would still recommend that to any homeowner but for construction use it’s lacking.

 

[4570Man]

Yes, my m59 lost both pumps at 75hr. Replaced under warranty. Good power in backhoe but slooow. loader was good but too weak for the big bucket. My m62 was better, but it was still slow digging compared to the 040.

I never had any major failures with the M59 but the power wasn’t equal to my KX 40, the durability wasn’t as good as the 40 and the boom speed is way behind the 40. I’ve been very happy with the 40 excavator. I need a bigger one to supplement it but that’s no fault of it’s and it does great at what a mini x was supposed to do.

 

[Hersheyfarm]

I went from running Deere 310’s in the 90’s, to owning a 580L in 2000, then m59, then m62, and now the 040. No backhoe compares to the 040 speed and smoothness. Of coarse the power is no where near the 310/580..

 

[LD1]

Ok. There's an example we can use to check the numbers from the advertising dept....and in this case they are going to look very good for Kubota.
HP = (flow (gal/min) * pressure (psi) all divided by 1716 to make the units come out right.

Turn it around with some basic algebra and we find that if we are looking at 24 gal/minute constant flow, the max pressure we can make with a 40 HP Yanmar motor runnng flat out is just under 3000 psi. That's close enough to call it a bullseye in my book.
Anyone saying they are getting higher flow rates with that same engine is exaggerating. Or whatever you want to call it.

BTW, our M59 has some of the sweetest, fast, accurate. and powerful hydraulics one could ever want. They just don't come better and most are not nearly so good. It will lift huge rocks and move a quarter inch controllably when stacking rock walls.
Was that just Luck? It was one of the first M59s built.
rScotty

They are probably adding the sum of pump flows that will never operate at the same time to full capacity

IE: let's say the same engine is powering both a 15gmp pump for the drive motors, and a 20gpm pump for the boom, and a 10gpm pump for an auxiliary.

So while the machine does have 45gpm capacity, it can never use that much

Drive the machine while using the boom/bucket one or both will reduce in speed