PTO Pump

[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