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

john_bud · 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.

The usual way to plumb is for the fluid to go from the pump to the loader control valve (which has a relief valve), out the PB to the hoe (which has a relief on the inlet, the boom and the dipper circuit normally) then back to the tank. The loader control valve has a route back to the tank for "used" fluid. Marked "out". For the pump to dead head - both the loader valve and the BH valve relief's would have to fail at the same time. Not likely. My guess is still with the selector valve.

Can you draw on a piece of paper the hydraulic circuit routing you used with the selector valve? That may help in ID'ing the root cause of the boo-boo.

On replacement pumps, if it fits it's gonna work. No need to buy a ford pump as they usually use Cessna (older units) or Eaton or other supplier pumps. Getting the location and size of the inlets and outlets correct and the shaft type/size are pretty easy to do. I don't think the original pump is salvageable. They usually balloon the case when dead headed.

jgbanshee · May 20, 2007

Which way does my pump operate (CW or CWW)? There is an arrow stamped on top of it but do I read that arrow from standing looking at the splined shaft side or from the backside of the pump?

jgbanshee · May 20, 2007

Alright, I got the pump off the tractor. The brand is Commercial. It looks to be cast iron and built in 3 sections.

jgbanshee · May 20, 2007

Here are some photos of the pump.

SPYDERLK · May 20, 2007

Not a progressive failure from the looks of the shaft. No discoloration as would happen with crack progression over time. Can you turn the shaft w vise grips? Unlikely for an internal failure to cause a pump to lock up on its own, but a possibility. Pump turns as if the part of the shaft nearest the arrow goes that way.
larry

jgbanshee · May 20, 2007

No, I cannot turn the shaft at all. It will not budge. The inlet side of the pump has that steel tube inserted for a rubber hose and hose clamp. Is that threaded in there or held in there some other way?

SPYDERLK · May 20, 2007

Its possible you had a pump failure that caused it to sieze, only coincidently associated with your mods. But it could be that overpressure broke something inside that stopped it and then the shaft broke. Have somebody that knows pumps disect it.
I dont know how the suction nipple is held in, sorry. Its not preventing you getting it apart is it? Maybe you can tell how its retained by looking at the inside
larry

rberg · May 21, 2007

Commercial Intertech was purchased by Parker Hannifin several years ago. If you go to the Parker website, Hydraulic Groups section you can find the Commercial Intertech pumps and catalogs. A search on Commercial Intertech should also pull up some websites for distributors or suppliers of other, similar pumps. You can use the code on the pump to identify your pump with all of the options used in the build up (shaft, ports, flow rate, rotation, etc). You should be able to get parts, a rebuilt pump, a new pump, or a Commercial clone pump fairly readily.

Do you use the selector valve to port oil to the FEL or BH or for some other purpose? Do you know if the selector valve is open center or closed center? You'll probably want to used an open center selector valve so the pump isn't dead headed when the selector valve is in mid stroke.