Hydraulic Pump Broke

jgbanshee · May 18, 2007

After replacing the loader valve with a new loader valve with power beyond on my Ford 345C to run my Bradco backhoe, I added a selector valve to the system. Well not ten minutes into operating the backhoe the front mount engine hydraulic pump shaft broke from the pump. What the heck is going on here? A new pump is like $1400.00. Should I consider taking the backhoe off this tractor? I can run the backhoe off the hydraulics from my JD 4300 compact and it operates fine. Now I am afraid to hook it to the 4300 to get it off the ground. Can someone tell me what could have happened? The shaft on the front pulley twisted the pump shaft right off. Like the pump stopped turning and the motor didnt.

JC-jetro · May 18, 2007

jgbanshee said:
After replacing the loader valve with a new loader valve with power beyond on my Ford 345C to run my Bradco backhoe, I added a selector valve to the system. Well not ten minutes into operating the backhoe the front mount engine hydraulic pump shaft broke from the pump. What the heck is going on here? A new pump is like $1400.00. Should I consider taking the backhoe off this tractor? I can run the backhoe off the hydraulics from my JD 4300 compact and it operates fine. Now I am afraid to hook it to the 4300 to get it off the ground. Can someone tell me what could have happened? The shaft on the front pulley twisted the pump shaft right off. Like the pump stopped turning and the motor didnt.

Is your pump gear driven off of crankshaft/cam shaft ?
it take tremendous amount of torque to twist off the shaft, can you post a picture of the shaft?
if you locked the gear by overheating or dead heading the pump something got to give. Did you know if your relief valve works?
Are the pump external gears okay? need pics.
Need to disassemble the pump and inspect. is you pump dual or single?

You may look at the link below, in about the middle of the thread it has close up pic of hydraulic pump. pictures may help some.

your best bit may be overhauling the pump, finding gasket kit is one thing but actual metal part is a whole different issue.

http://www.tractorbynet.com/forums/nh-owning-operating/90819-my-f-1700-testing-my.html

jgbanshee · May 18, 2007

The pump is mounted about 1.5 ft from the front face of the engine. Connecting the two together a shaft with universals. One end bolts to the crank pulley with two bolts and the other slides over the pump shaft. I am not sure whether the pump shaft is splined or keyed. The pump is a gear type pump not a vane or anything else. I am not sure if it is dual or single but it only operated the loader before I added the backhoe.

Could something have happened to the pump when I split the loader control valve? I am sure that the backhoe is open center and fairly sure that the relief valve on BH works but I am not sure. My JD has power beyond so i guess that the loader valve could have been relieving when I bottomed out a cylinder on the BH, right?

Here is the diagram for my reservoir and pump.

john_bud · May 19, 2007

jgbanshee said:
After replacing the loader valve with a new loader valve with power beyond on my Ford 345C to run my Bradco backhoe,

I added a selector valve to the system.

Well not ten minutes into operating the backhoe the front mount engine hydraulic pump shaft broke from the pump.

I have the feeling that you shot your foot with that selector valve. Your symptoms are to be expected for a pump that is dead headed. If you have PB for the new loader valve, why put in the selector ??? It shouldn't be needed.

Questions:
Is the selector plumbed correctly?
Is it possible that the selector was bumped into a closed position or operated while the engine was running? That will kill the pump and kill it right now.

Sorry for the mishap. Have you tried Surpluscenter.com for a new pump? If they have one (CCW rotation IIRC) for around 400.

jb

KJM · May 19, 2007

My comiserations - this is getting expensive!

I'm with John_Bud on this one - something has stopped the flow - and I'd bet the selector valve. Or there is some substantial flow restriction - either way, the pump has been hydraulically locked (dead-headed). On my pump, there is a key - which I'm 100% sure would shear and protect the pump. Still, hydraulic systems normally let go on a hose or something like that before twisting the pump shaft like cheese.

You didn't plumb the selector valve to isolate either the B/H or FEL? I think the split loader valve established that the flow rate through the B/H was either too low or there was some kind of hydraulic plumbing whoopsie. If it was "too low" then the excess flow means increased pressure and hence load on the pump. Which could be the problem, if that's whats been done..

Just a thought. Best of luck.

/Kevin

jgbanshee · May 19, 2007

I think I figured out my problem. Since I had a direct line from the pump (pressure) to inlet on backhoe valve and a direct line from the outlet of BH valve to the tank, the working valve was directing all of the flow to the cylinder and when I bottomed that cylinder out the flow dead headed the pump. Now, IF I used the PB port on my loader valve and connected a line from there to the inlet of the backhoe and the outlet line of the backhoe tees into the outlet of the loader valve then to tank, I should not have a problem. Right?

SPYDERLK · May 19, 2007

jgbanshee said:
I think I figured out my problem. Since I had a direct line from the pump (pressure) to inlet on backhoe valve and a direct line from the outlet of BH valve to the tank, the working valve was directing all of the flow to the cylinder and when I bottomed that cylinder out the flow dead headed the pump. Now, IF I used the PB port on my loader valve and connected a line from there to the inlet of the backhoe and the outlet line of the backhoe tees into the outlet of the loader valve then to tank, I should not have a problem. Right?

It sounds as though your BH relief valve does not work. As you say in your new plan, plumbing from the PB should be OK since that line is protected by your loader relief, which must be functioning or you would have had prior problems. Id look into that BH relief situation. It has cost you plenty already.
larry

JC-jetro · May 19, 2007

At any rate the problem to solve now is the pump. We need post mortum autopsy of the pump to see if it can be overhauled. Since the shaft twisted off is not the pump shaft

then there may be a slight chance. The clearance between the gear and pump case is so tight that overheating, dead heading can can cause a lot of friction. usually the pump housing is aluminum and gear steel and aluminum can expand more in comparison to steel gears, but still get pretty tight in there In a hurry. if damage is not bad pump may be repairable. slight abrasion of the pump case costs pump flow. In other word you may get lucky pump some at the lower pressure

jgbanshee · May 19, 2007

I am told by my local Ford dealer (deals Bradco attachments) that each section of the bh valve has its own relief and then there is a main relief for the whole valve. Is that true? So, if I use PB then I should have NO problems? After I take the pump out I will be looking for a name plate and information about it cause if I woulc fine a new replacement for say a third of the price from Ford I probably will just buy a new one. I am told by Ford that it is probably a Cessna or maybe Eaton. I found a Cessna that is really close in specs for like $400 something.

SPYDERLK · May 19, 2007

jgbanshee said:
I am told by my local Ford dealer (deals Bradco attachments) that each section of the bh valve has its own relief and then there is a main relief for the whole valve. Is that true? So, if I use PB then I should have NO problems? After I take the pump out I will be looking for a name plate and information about it cause if I woulc fine a new replacement for say a third of the price from Ford I probably will just buy a new one. I am told by Ford that it is probably a Cessna or maybe Eaton. I found a Cessna that is really close in specs for like $400 something.

It sounds as if two relief valves would have had to fail in the BH if he is correct. I dont know, but what he says sounds plausible. That leaves us with a mystery as to what went wrong - its extremely unlikely for a relief to malfunction, much less two. Do you know the history of the BH? Could someone have adjusted the valves high so that the springsholding the popoff are almost completely compressed. In this case the valves wouldnt relieve high flow effectively because the valve could not open far enuf. The way I see it, plumbing the BH thru your loader PB port should be able to protect the pump from the downstream problems, if any. For the future I think it is important the get a good understanding of what happened.
larry