PTO Pump

[Dougster]

I've run the 6000 on 1000rpm PTO at about 1200rpm with this hoe as well. Don't like the idea that I may lug the engine down doing that so I stick with the 540PTO. I have run the hoe at about 1500rpm engine and it is somewhat more "responsive", but see no reason in running up against the bypass any more than I have to....just me I guess. Hey, you got your rear tires filled??? If not you better....BobG in VA

Nope... can't afford the extra weight. I'm already maxed out on my 10K equipment trailer's net capacity (and my current truck's rated towing capacity) with the tractor, FEL, BH, thumb and 78" HD bucket or root/rock grapple. Should have bought a 12K trailer.

Remember, I've got a 509... supposedly much less *strain* on the tractor than the 511 (or so I'm told).

But even near 2,500 engine RPM (~9.0 to 9.5 GPM tractor flow) I am not exactly thrilled with my 509's digging power. Part of it is probably a lack of sufficient BH operating experience and technique... but I really fear the day that I take on a stump too large & nasty for the 509 operating at the lower end of the recommended flow range and embarrass the heck out of myself in front of a client. That very next day will be the day the order goes in for the Prince PTO pump!!!

Dougster

 

[SPYDERLK]

Quote Dougster: "Nope... can't afford the extra weight. I'm already maxed out on my 10K equipment trailer's net capacity (and my current truck's rated towing capacity) with the tractor, FEL, BH, thumb and 78" HD bucket or root/rock grapple."

You run a 78" bucket? I have trouble enuf pushing a 72" with the 7520. Im thinking of cutting one down to 48" for tree removal.
larry

 

[Dougster]

You run a 78" bucket? I have trouble enuf pushing a 72" with the 7520. Im thinking of cutting one down to 48" for tree removal.
larry

All I've seen on 7520's are those monster 84-inch wide, 25-inch deep HD buckets. How did you end up with a 72-incher??? If it's like my original "light-duty" 72-incher, it's probably a pretzel by now in front of a 7520!!!

Anyway... I needed a true "heavy-duty" bucket immediately for a job and Jeremy steered me to this 78-inch wide, 15-inch deep KMW-made HD bucket for very short money. He wanted me to get the 72-inch version, but everyone was sold out. 72-inch would have been better overall... but I gotta tell you: that nasty black 78-inch mini-monster is really quite impressive at times! I also recently bought a toothed skidsteer stump bucket, which is great for highly focused FEL digging.

While I am way behind schedule due to a few unexpected distractions and unplanned expenses, I still plan to pickup that 66" toothed skidsteer bucket for really ugly digging... and convert the old 72-inch light duty bucket into a somewhat heavy-duty toothed bucket as well... possibly using a toothbar in lieu of welded teeth so I can attach (and use) a massive hardened cutting edge. In fact, the welder I chose to do the mods is back from vacation today and left me a message. Gotta get going on that project... along with six others!!!

Dougster

 

[LarryRB]

when I had my 4110, I put a Fisher snow plow blade on the bucket for a cutting edge,,, Won't wear out anytime soon.. Then took a torch and cut it back, leaving the newly installed blade around 75-76 inches across.,

 

[Tim_in_IA]

Nope... can't afford the extra weight. I'm already maxed out on my 10K equipment trailer's net capacity (and my current truck's rated towing capacity) with the tractor, FEL, BH, thumb and 78" HD bucket or root/rock grapple. Should have bought a 12K trailer.

Remember, I've got a 509... supposedly much less *strain* on the tractor than the 511 (or so I'm told).

But even near 2,500 engine RPM (~9.0 to 9.5 GPM tractor flow) I am not exactly thrilled with my 509's digging power. Part of it is probably a lack of sufficient BH operating experience and technique... but I really fear the day that I take on a stump too large & nasty for the 509 operating at the lower end of the recommended flow range and embarrass the heck out of myself in front of a client. That very next day will be the day the order goes in for the Prince PTO pump!!!

Dougster

Dougster,

I don't think the prince will make the hoe any stronger. Will make it faster though. If I understand it right the limiting factor of hydraulic force is pressure against surface area of the cylinders internal plate. When you go a higher GPM pump you can just move around faster. I run a little higher than Bob, around 1800rpm on the 6500 w 511 hoe. I have the swing speed turned down a bit so it doesn't throw me side to side, but I find I can scoop faster this way.

When I first started using the hoe I tried to dig big buckets of stuff. As I get better, I learn that it is actually faster to skim and peel the material to fill the bucket, and also makes for a lot less wear on the machine.

I guess I am saying if the 509 is embarrasing you you'd better look at the 511 or bigger .

The reason I like the idea of the prince pump is that it is a well known pump and available everywhere. The bradco is somewhat more secretive and mysterious, and with the gearcase oil issues I've been having I'd go prince next time. Just make sure that the prince will fit between the hoe and the tractor, especially if you are going oversized.

 

[Dougster]

Dougster, I don't think the prince will make the hoe any stronger. Will make it faster though. If I understand it right the limiting factor of hydraulic force is pressure against surface area of the cylinders internal plate. When you go a higher GPM pump you can just move around faster. I run a little higher than Bob, around 1800rpm on the 6500 w 511 hoe. I have the swing speed turned down a bit so it doesn't throw me side to side, but I find I can scoop faster this way. When I first started using the hoe I tried to dig big buckets of stuff. As I get better, I learn that it is actually faster to skim and peel the material to fill the bucket, and also makes for a lot less wear on the machine. I guess I am saying if the 509 is embarrasing you you'd better look at the 511 or bigger . The reason I like the idea of the prince pump is that it is a well known pump and available everywhere. The bradco is somewhat more secretive and mysterious, and with the gearcase oil issues I've been having I'd go prince next time. Just make sure that the prince will fit between the hoe and the tractor, especially if you are going oversized.

Hi Tim - This issue of the relative effects of flow vs. pressure has been tossed around here before and you are fundamentally right. But it doesn't explain some of the observed "real world" behavior of the 509/511 backhoes that may be more related to controls and control settings. I know that on my own machine, I can do a lot better working on a stump at 9 to 9.5 GPM than I can do at 5 or 6 GPM. If it was only about the pressure, this shouldn't matter... all the way down to 1 GPM! Yes, my digging would obviously be slower, but not more effective... but it *IS* clearly far more effective at the higher flow rate.

I still remember my original selling dealer... the only one I know outside of TBN with significant PTO pump comparative experience... saying that I would mostly realize an increase in speed, but that I would also see about a 10% increase in what he unscientifically called "digging power" (possibly due to a marginally higher pressure delivered by the PTO pump vs. tractor system???). The bottom line after living with this beast for one full year is that I think I need that extra 10%.

Fortunately or unfortunately, my struggling little tractor and backhoe business has been 90+ percent call for tractor services (FEL+3-Point) and only ~10 percent (or less) call for backhoe. The good news is that I've not been embarrassed yet. The bad news is that I am getting stale in regard to backhoe operation and technique, especially in regard to large stumps. I fully realize this lack of continual operating experience is hurting me.

No 511 going on this particular machine I'm afraid... but I am actively searching for a second machine and possibly even a third. As long as I buy right, I am willing to take even more money out of my savings and house. Of course, "buying right" is a lot easier said than done... but I am looking at both smaller machines (for highly delicate residential "over septic" work) and larger machines that would either include a larger, stronger backhoe or allow one to be added. One thing I've learned is that no one machine can be ideal for all jobs. Having back-up and choices would be a very cool situation.

I am not "dissing" the 509 at all. Initially, I was very impressed with it and I have no regrets about having bought it. But as time has gone on, its limitations have become more clear... and the eventual need for a PTO pump more apparent.

Dougster

 

[Tim_in_IA]

Dougster,

this is interesting. I wonder if there is some kinetic energy built up in the movement of the hoe itself or if this could be attributed to the lugging that Bob referred to? That is, at the higher GPM the differing factor was actually the higher engine RPM and not the flow rate??

Pump efficiency is probably another issue. I forget, do you have a gauge hooked up to your setup? I have no way of knowing what my GPM is.

 

[DavesTractor]

Tim, when hooked to the tractor hydraulics, we have the tractor pressure relief and the backhoe pressure relief in the system. When hooked to the PTO pump, we eliminate one relief. If the tractor relief is set softer than the backhoe relief, that would explain things. Clearly flow equals speed, not more power, but I have seen the same thing. With a PTO pump, it seems a little stronger. I am guessing there is a slight kenetic thing happening before the bypass fully opens, but that would not account for much.

 

[Dougster]

Dougster, this is interesting. I wonder if there is some kinetic energy built up in the movement of the hoe itself or if this could be attributed to the lugging that Bob referred to? That is, at the higher GPM the differing factor was actually the higher engine RPM and not the flow rate?? Pump efficiency is probably another issue. I forget, do you have a gauge hooked up to your setup? I have no way of knowing what my GPM is.

No pressure gauge yet (still on the "to do" list), but that would be quite useful if there is a tractor pressure problem or malfunctioning BH bypass.

Clearly, backhoe speed, engine behavior/response at low RPM, tractor & backhoe controls & setpoints all play into this. Not so much for pump efficiency unless there is unusual pump wear. But the bottom line is that even at full rated engine RPM, I am currently operating the backhoe at the low end of Bradco's 9-12 GPM recommended range and well below the 14 GPM bypass setpoint. That can't be a really great thing for achieving tip-top performance. The only way I'll ever know is to try a similar tractor to mine with a 509 outfitted with a known output PTO pump. Sure wish I could find one.

Dougster

 

[SPYDERLK]

All I've seen on 7520's are those monster 84-inch wide, 25-inch deep HD buckets. How did you end up with a 72-incher??? If it's like my original "light-duty" 72-incher, it's probably a pretzel by now in front of a 7520!!!
Dougster

I ordered my tractor with the 72 HD bucket so I could do woods work. Its identical except width to the wide buckets, so it would actually be a little more durable than they. I am told it is the narrowest one available for the 7520. Still, I am having trouble keeping the bottom edge straight when toppling trees. Im going to have to add some reinforcement I guess.
larry