Backhoe Need help with Bradco 6LD backhoe pump

[Grandad4]

Grandad4, I was able to reach them just the other day and they emailed me the needed information. I just have to get back to them for a price. One place quoted a price around $1000 for the pump. After I regained consciousness, I started looking around. Still looking at this time. I need a pump that can produce 4 to 6 GPM at either 540rpm or 840 rpm. I think the previous owner might have Mickey Moused the setup. I'll get a few photos of the PTO area and post them, hopefully there's another B1550 out there to compare to. Mark

I was more thinking they would tell you the gpm and psi specs for the backhoe so you could find you own pto pump. There are any number of aftermarket sources for such pumps, no doubt a bit more economical than the OEM pump. Shoulda known they'd first try to sell you theirs!

 

[bumperm]

As Grandad4 said, just need the specs and a new PTO pump will run between $350 and maybe $550 tops, depending on if you get it on ebay, surpuscenter etc.

Some PTO gear pumps have a max pressure of 2000 psi, some like Prince are 2250 psi, there's a few listed at 2500 (that's the highest pressure I could find).

For hydraulic horsepower the formula is HP= (PSI) X (GPM)/1714 - - that would be 100% efficient, so use 1500 or so instead of 1714. Also, it's good to size the pump to what your backhoe needs as the more is bypassed the greater the heat from friction.

A rule of thumb is that reservoir tank size in gallons should equal pump flow in gpm, so that may give you a hint as to what your dead pumps flow was.

 

[BobG_in_VA]

As Grandad4 said, just need the specs and a new PTO pump will run between $350 and maybe $550 tops, depending on if you get it on ebay, surpuscenter etc.

Some PTO gear pumps have a max pressure of 2000 psi, some like Prince are 2250 psi, there's a few listed at 2500 (that's the highest pressure I could find).

For hydraulic horsepower the formula is HP= (PSI) X (GPM)/1714 - - that would be 100% efficient, so use 1500 or so instead of 1714. Also, it's good to size the pump to what your backhoe needs as the more is bypassed the greater the heat from friction.
A rule of thumb is that reservoir tank size in gallons should equal pump flow in gpm, so that may give you a hint as to what your dead pumps flow was.

I believe your "rule of thumb" is correct....my 14gpm pump has a 15gal res. BobG in VA

 

[Carrizokid]

Hello Grandad4, What I found was that this Bradco 6LD BH needs a 4-6 gpm rate pump @ 540 rpm. Operating Pressure is 2250 psi. I contacted a distributor for Prince Mfg in Houston, and they are currently looking for something that might work. I did find a 7 gpm @ 540 rpm at about $400. It's PSI was 2000.
I changed out the hydraulic fluid a few months ago, but can't remember the number of gallons used. Based off what Bumperm mentioned below, I would guess the hydraulic fluid reservoir to be no more than 6 gallons. I did find a Prince PTO pump for $400, it's rated at 7 gpm at 540 rpm, but the operating pressure is only 2000 psi. Any opinions on how this pump might effect the operation of the BH?

Given all these factors, this might be way the owner previous to me, decided to Gerry rig the PTO pump. As always, I appreciate any and all opinions and advise.
Mark

 

[Grandad4]

Hello Grandad4, What I found was that this Bradco 6LD BH needs a 4-6 gpm rate pump @ 540 rpm. Operating Pressure is 2250 psi. I contacted a distributor for Prince Mfg in Houston, and they are currently looking for something that might work. I did find a 7 gpm @ 540 rpm at about $400. It's PSI was 2000.
I changed out the hydraulic fluid a few months ago, but can't remember the number of gallons used. Based off what Bumperm mentioned below, I would guess the hydraulic fluid reservoir to be no more than 6 gallons. I did find a Prince PTO pump for $400, it's rated at 7 gpm at 540 rpm, but the operating pressure is only 2000 psi. Any opinions on how this pump might effect the operation of the BH?

Given all these factors, this might be way the owner previous to me, decided to Gerry rig the PTO pump. As always, I appreciate any and all opinions and advise.
Mark

There are some guys on TBN here with vastly more hydraulics knowledge than me (check the Hydraulics subforum), but I'd probably give one of those $4-500 pumps a try. My backhoe runs off a PTO pump and I've found my skill level as an amateur backhoe operator is well matched with a slower pto rpm, giving less flow and pressure than running at the full 540 would provide. Now that just me... if you're demanding peak, all-out performance, maybe you wouldn't be happy with anything less than full factory original operation.

 

[dfkrug]

I did find a Prince PTO pump for $400, it's rated at 7 gpm at 540 rpm, but
the operating pressure is only 2000 psi. Any opinions on how this pump might effect the operation of the BH?

Mark, you set the hoe's operating pressure with the adjustable relief valve on the hoe's stack valve. Go
ahead and use the Prince pump and set the RV pressure to 2000psi. You need a gauge to do that, and
you may want to back off the adjuster before you run the test.

I have used Prince valves and pumps and like them.

 

[Carrizokid]

Bumperm - Can you explain the hydraulic horsepower part for me? The B1550 has about 18 hp, so I'm going to assume that it's a few less at the rear PTO. Using the formula for 7 gpm PTO pump I get HP = to 8.75. [2000psi x 7gpm/ 1714].

The reservoir tank on this Bradco BH is 6"x8"x19.5". I calculate this to be 936 cubic inches. Which boils down to a measly 4.05 gallons of hydraulic fluid.

It appears that there are not many PTO pumps that move less than 7 gpm. I found one from Prince that's 7 gpm @ 540 rpms. Rated to 2000psi. I have contacted Prince Mfg's rep and have them looking to see if they have a pump this is 4 to 5 gpm.
Thanks, Mark

 

[Carrizokid]

Thank you for info. I don't have any idea where the relief valve is on this BH. Or if it even has one at this time. Most likely, once I got the BH on the tractor I would truck it into town to one of the mechanics, and let them set it. I found this company: P & J Commercial Products, they have a relief valve for $40 along with a torque arm bar. They have gauges for $20.00. Would the gauge just screw into the relief valve? I'll let you [all] know what I find out from Womack [Prince Mfg dist] in Houston. Again thanks to everyone. Mark

 

[dfkrug]

I don't have any idea where the relief valve is on this BH. Or if it
even has one at this time.

Since you have a parts manual for the hoe, it will tell you where the RV is. I am sure you
have one on the hoe's valve stack.

7GPM at 540RPM is fine for your application. You will prob not be running at the full
engine speed to get the 540RPM, so you will get maybe 4-5 GPM when the engine is
running somewhat slower.

Test the RV at any work port by disconnecting a hose at the cylinder and operate
that valve with the gauge connected to the hose. Be careful to cap off the open
cyl port.

 

[Carrizokid]

Dfkrug - Thank you for the advice regarding the 7 gpm pump. [I have often wondered what the actual PTO speeds are while the engine is running at different rpms]. I think this particular backhoe is a 1986 model. From reading the parts manual it appears that there were several different valve assembles used at that time. One of them does appear to have a means of relief adjustment. [ I'd just have to figure out if this is the assemble that I have. ]
Valve assembles are beyond my skill sets and current working environment to tear down, analyze, repair and then reassemble.
From what you advised, I'm pretty much on board with the 7 gpm pump at $400 versus Bradco's $1000 version.

In regards to testing the RV or checking the operating pressure as you mentioned. Do I need to do that if the PSI of the 7 gpm pump is rated at 2000 psi and the backhoe's operating pressure is 2250 psi? Would I still need an adjustable relief valve?

Mark