PTO Pump

[Dougster]

Yea, your right, here is what it says:
Optional hydraulic PTO pump kit available. Recommended for heavy-duty application, when used on Mahindra 00 4WD Series Tractors
If I had a good dealer, I would ask them this question: Why?

Maybe they consider it a little obvious in my case! Perhaps less obvious in yours!

It should read: "Recommended when used on any tractor with hydraulic flow specification under 9-12 GPM and on Mahindra 00 4WD Series Tractors. Yes?

Dougster

 

[SPYDERLK]

I here what you all are saying about oil temperature. The 7520 has a notoriously small sump for its 17gpm capacity - about 7G i think. The oil does get to about 160 during hyperactive tractor or BH use in 90*T. This seems like a healthy working T for the oil and the tractor contained hydraulics, because I think the heat is expected and accomodation, within the controlled relief pressures of the system, are designed in. Accessory equipment however can be loaded beyond these pressures when the valve controling a function is centered and tractor force or bouncing is brought to bear on that function. Paticularly when pushing with a loader or carrying a heavy load across bumps or lowering with a quick stop the cyl pressures can reach multiples of relief pressure. Hot seals pop easier. A BH is not as taxed since overpressures are very limited in duration-akin to a spike, rather than sustained as when the tractor pushes a loader. In such loader cases there can be pressures well above cyl and hyd hose rating for several seconds at a time. Hoses probably do better when hot than cyl seals since the hose is steel reinforced.
Thats the way I see the heat problem anyway.
larry

 

[DavesTractor]

I find it interesting that the 6000 4WD is the only unit for which Mahindra goes out of their way to recommend the PTO pump kit for the 509/511 backhoes in their literature. It must be like BobG_in_VA says: Kinda marginal on hydraulic oil volume... a possible overheating concern? On the other hand, here I am with a mere 7.87 GPM flow (vs. your 11)... not even in the Bradco recommended range at design RPM... and no specific recommendation for the PTO kit. Makes you wonder a bit about their thought process, doesn't it?

Dougster

Dougster, the 00 series have separate hydraulic tanks, they do not share with the transmission fluid. So you have a relatively small reservoir (heat concerns) and a flow rate that is near the bottom of what is recommended for the hoe. Combine those factors, and the PTO pump/tank is the way to go if you are going to use it a lot.

 

[Dougster]

Dougster, the 00 series have separate hydraulic tanks, they do not share with the transmission fluid. So you have a relatively small reservoir (heat concerns) and a flow rate that is near the bottom of what is recommended for the hoe. Combine those factors, and the PTO pump/tank is the way to go if you are going to use it a lot.

Ahhhhh... that explains a lot! Thanks Dave! I knew about the tank from a previous post, but I still thought it was somehow integrated with the transmission... adding extra capacity instead of replacing it. Now I know!

Dougster

 

[bindian]

Running with the rpm at 2000 and at the Pto shaft symbol on the tach (around 1900) didn't make any difference. Either rpm is a lot better than 1700 rpm in BH performance. The heat was about the same as running it at 1700 rpm. I checked it after digging out the sweetgum stump while filling the hole and recontouring the ditch with a lot of loader work. It was hot to the touch no matter what I was doing. I didn't notice any cooking odor like before. I think the heat cooks the paint a little and that is all. I did put the bucket back in the standard position for easier undercutting the stump dirt. After numerous hours the stump broke loose. But it was too big (and suction stuck in the mud as water had half filled the hole over night ) to lift out with the loader. I tried carefully to lift it out with the loader with the BH fully extended and still the rear end was coming off the ground. About this time I was thinking of you guys with filled tires. The only way I got it out of the hole was dig a ramp and hoe it out a little at a time. The first photo shows the stump half way out of the hole. The second photo shows it all the way out and the third photo shows after I was done for the day. I will slope the far side tomorrow. So it would seem the BH works better with way high RPMs. Guess I don't need a PTO Pump after all. So now I can see about getting that 8 foot disc.
hugs, Brandi

 

[Dougster]

Running with the rpm at 2000 and at the Pto shaft symbol on the tach (around 1900) didn't make any difference. Either rpm is a lot better than 1700 rpm in BH performance... ...So it would seem the BH works better with way high RPMs. Guess I don't need a PTO Pump after all. So now I can see about getting that 8 foot disc.
hugs, Brandi

That's excellent news.

I'm confused though. According to the Mahindra specs, you have a single speed setting (540 RPM) PTO on the 6520 4WD which turns 540 RPMs at 2,187 engine RPMs. Why would there be a marking on your tach at 1,900 RPMs? Has the spec changed? 1,900 RPM seems a little low to get your full 55 PTO HP.

But regardless... getting back to the backhoe, assuming your full 11.4 or 17 GPM hydraulic flow is achieved at the rated 2,300 engine RPM, that means you are now running the backhoe with either 9.42 to 9.91 GPM or 14.04 to 14.78 GPM flow depending on which hydraulic pump (6520 standard or 7520 monster) you've really got in there. Back at 1,700 RPM, you were either at 8.43 or 12.57 GPM depending on which pump you've got. Now you are either running just inside the lower end of the Bradco recommended (9-12 GPM) range... OR... you are running just a hair above the bypass valve opening setpoint... theoretically the best anyone could ever hope to do!!!

This has a great deal of significance to my own situation... i.e., upgrade to "new" 4110 pump (if technically possible) at 9.5 GPM or go with a PTO pump at 12-14 GPM... so I'd LOVE to know with certainty which hydraulic pump you've really got in there!

Dougster

 

[SPYDERLK]

Quote Dougster: This has a great deal of significance to my own situation... i.e., upgrade to "new" 4110 pump (if technically possible) at 9.5 GPM or go with a PTO pump at 12-14 GPM... so I'd LOVE to know with certainty which hydraulic pump you've really got in there!

In the 7520 thread I believe Brandi said that her loader went up in 5sec at 1700rpm. I think that was an estimate. If her time is accurate she has a 23gpm pump. After I eliminated the air leaks in my suction line my loader sped up so it went up in 5s at 2500rpm. I used a sweep second hand and did not verify true engine rpm. I will one day do it with a stopwatch and verify engine rpm w a strobe. 4.9s raise time on the ML275 would verify 17gpm delivery.
larry

 

[MtnViewRanch]

Not that it affects anybody here, but I used my Case 580E for a few hours this weekend digging out some scrub oaks and after a couple of hours I felt the stick hydraulic to see if it was warm or hot and it was only warm. Not that I was working it hard, just sort of plugging away.

 

[Dougster]

In the 7520 thread I believe Brandi said that her loader went up in 5sec at 1700rpm. I think that was an estimate. If her time is accurate she has a 23gpm pump. After I eliminated the air leaks in my suction line my loader sped up so it went up in 5s at 2500rpm. I used a sweep second hand and did not verify true engine rpm. I will one day do it with a stopwatch and verify engine rpm w a strobe. 4.9s raise time on the ML275 would verify 17gpm delivery.
larry

Hi Larry - I'll avoid my usual soapbox speech about proper test design and test measurement uncertainty, etc. Suffice to say that some informal tests (and informal test results) are a lot better than others. But this is less about pump or system performance... and more about what the heck pump is actually mounted on there! Unless the two pumps (11.4 GPM and 17 GPM) are externally identical... and marked the same... or somehow hidden so they can't easily be seen or photographed... the smart folks here on TBN should be able to figure out this mystery easy!

Dougster

 

[bindian]

When I checked my loader raise time, I just counted 1001, 1002, 1003. It was a rough estimate. I didn't have my watch on me. I need to run it with a stop watch.

My Mahindra salesman told me for the 6000....the PTO Pump was 14.3 or 14.6 gpm. I made myself a note to ask my parts guys the part numbers for a 7520 and 6520 pump.

I was wondering about my PTO shaft symbol, as my Ops manual shows it about 2186 rpm. My PTO engaged light comes on with clutch engagement, not when it gets to 540 rpm, like I read it in the manual.
hugs, Brandi

 

[Dougster]

When I checked my loader raise time, I just counted 1001, 1002, 1003. It was a rough estimate. I didn't have my watch on me. I need to run it with a stop watch.

My Mahindra salesman told me for the 6000....the PTO Pump was 14.3 or 14.6 gpm. I made myself a note to ask my parts guys the part numbers for a 7520 and 6520 pump.

I was wondering about my PTO shaft symbol, as my Ops manual shows it about 2186 rpm. My PTO engaged light comes on with clutch engagement, not when it gets to 540 rpm, like I read it in the manual.
hugs, Brandi

The bottom line is: Wouldn't you really like to know for sure if you've got the 11.4 vs. 17 GPM pump? If it were my 6520, I'd be under there taking pictures and copying down markings in a heartbeat!

Of course... don't let my totally selfish motive of mapping out 509/511 backhoe performance vs. flow rate influence you!!!

Dougster

 

[Tim_in_IA]

I have a 6500 and the mahindra pto pump. I must say the only trouble I've had with the backhoe HAS been with the pump. The gearcase leaks and bradco will not give me a new pump. One time the gearcase leaked so bad that the shaft siezed and snapped inside the pump. They repaired the shaft. "I think they welded it as the pump shimmies when it runs" and it still sqeals like there is friction. I am still under warranty. I think they should have given me a new pump.



When it fails I'll buy a prince...

 

[Dougster]

When it fails I'll buy a prince...

Hi Tim - I think the Prince pumps look pretty good... especially the cast iron ones. What brand of pump do you have now? Did you buy the PTO package directly from Bradco or from Mahindra? In other words, whose warranty issue is this? Bradco's or Mahindra's?

Dougster

 

[Tim_in_IA]

Hi Tim - I think the Prince pumps look pretty good... especially the cast iron ones. What brand of pump do you have now? Did you buy the PTO package directly from Bradco or from Mahindra? In other words, whose warranty issue is this? Bradco's or Mahindra's?

Dougster

I bought it from Mahindra when I got the tractor but it is a bradco pump with the itallian gearcase.

 

[BobG_in_VA]

I bought it from Mahindra when I got the tractor but it is a bradco pump with the itallian gearcase.

Ditto for my 6000. My pump, when first installed, really whinned and squeeled. My good friend was with me when I fired it up the first time. He said "let it blow"...I did and got a new pump out of it...This one has lasted since. I'm with Tim, if this one ever goes (probably has 12-15hrs on it), I'll get a Prince. I'm hopin' this one only lasts about 4000 hrs though....Oh, as far as whether Brandi has an 11.4 or a 17gpm, what's the big deal as the 511 only requires 11 gpm? BobG in VA who still likes that PTO pump as the price of Diesel is much less at 1200 rpm than at 1700....

 

[Dougster]

Oh, as far as whether Brandi has an 11.4 or a 17gpm, what's the big deal as the 511 only requires 11 gpm?

Hi Bob - It's only a big deal to me as I decide whether to continue pursuing the idea of upgrading to a 9.5 GPM tractor pump or a 12 to 14 GPM PTO pump. At whatever flow level Brandi found she was getting decent performance is probably the level I should try to shoot for. Depending on which pump she actually has, it could have been high 9's or just over 14 (the bypass valve setpoint) GPM. She's now doing great but I am still "out of range"! The better I get with this 509, the more I realize that I could use a little more power.

Besides, if it were your 6520, wouldn't you like to know what you actually bought?

Dougster

 

[SPYDERLK]

OK, here are some 7520 pump times for full extension of the 275 loader. They are timed HOT ~ about 160F -I was clearing land at the edge of a field for a couple hours - then took readings. Full extension is 5.5 quarts.
* 2500rpm -- 5sec -- 16.7gpm
* 2250 -- 6sec -- 13.9gpm
* 2000 -- 7sec -- 11.9gpm
* 1750 -- 8sec -- 10.4gpm
There are some small rounding errors in the gpm figures.

The times were done with a sweep hand stopwatch with 0.2sec resolution, were quite repeatable, and I believe slightly conservative since I pressed the button as I operated the handle and again as I saw loader stop. Rpm was as indicated on tach while servicing the raise load. Pump rpm is 36/33 engine rpm.

If you plot those numbers you see that the pump is more efficient at higher speed. Less time per revolution for internal leakage.
larry

 

[Dougster]

OK, here are some 7520 pump times for full extension of the 275 loader. They are timed HOT ~ about 160F -I was clearing land at the edge of a field for a couple hours - then took readings. Full extension is 5.5 quarts.
* 2500rpm -- 5sec -- 16.7gpm
* 2250 -- 6sec -- 13.9gpm
* 2000 -- 7sec -- 11.9gpm
* 1750 -- 8sec -- 10.4gpm
There are some small rounding errors in the gpm figures.

The times were done with a sweep hand stopwatch with 0.2sec resolution, were quite repeatable, and I believe slightly conservative since I pressed the button as I operated the handle and again as I saw loader stop. Rpm was as indicated on tach while servicing the raise load. Pump rpm is 36/33 engine rpm.

If you plot those numbers you see that the pump is more efficient at higher speed. Less time per revolution for internal leakage.
larry

Hi Larry - This is very interesting. I was apparently using an incorrect baseline assumption (i.e., ~2,300 RPM for full rated pump flow). Based on your test results, at ~1,900 to ~2,000 RPM, Brandi was likely getting no more than 11.9 GPM flow even if equipped with the 17 GPM "7520" pump. The good news is that this would still place her at the high end of Bradco's 509/511 recommended range of 9 to 12 GPM.

On the other hand, if she has the 11.4 GPM pump... and if it exhibits similar pump characteristics, etc... she was possibly putting out no more than maybe 8.0 GPM at ~2,000 RPM... almost as low as I am now at full rated engine RPM/pump flow.

No question about it... I'd sure as heck like to know which pump is on that nifty new 6520!

Dougster

 

[bindian]

Hey guys,
I glanced over y'alls posts this morning at work before heading home. I then realized it wasn't my tractor I timed. But one on the dealers lot................. Default Re: Update on all 7520s post #104
Hey y'all,
I just timed the 6520 4WD on my dealers lot. It would be mine if it had the skid steer option. I warmed it up for a minute, as it is 77 degrees out side, cranked it up to around 1650 rpm and timed the loader raise. I didn't rev it higher because the fuel guage was sitting on E. It took under 6 seconds to raise the loader to max height.
I timed my 6520 this morning after a quick warm up and at 1700 rpm, it rasied the bucket right at 9 seconds. At 2000 rpm, it raised the bucket right at 8 seconds. I did this 3 times and got the same results. I used my watch. I didn't look at the bucket at all, but felt the bucket hitting the top "stop". I then timed it just counting like I did on the dealers lot...1001, 1002, 1003 and got to 1006 when the bucket hit the top, 6 seconds. 18 more hours on the Hobbs and I will time it with higher rpm.
hugs, Brandi

 

[SPYDERLK]

Brandi, is there any initial jerkiness as you raise your loader the 1st time after sitting overnite. if so you have a suction side air leak. If not you have the 11.9 pump or, much less likely, a pressure side leak to the sump return or PB line when you are raising the loader.
larry