L 1200 Front End Loader Hydraulic Pump Case Cracked

[mllkn6]

The flow volume of a hydraulic pump is dependent on two factors: the physical size of the pump and the speed of rotation. So while it sounds like your new pump is physically bigger, the 540 rpm rotational speed of the PTO may be well below the speed of the original front-mounted pump. Hence the lower output and the slower cycle times.

You can actually measure the GPM output by calculating the volume of liquid required to raise and to lower the arms (they will be different volumes due to the rod diameter) and then time the cycles. Average over 4 or 5 cycles. If it works out to 3.6gpm then you are getting the rated flow out of that pump and can't hope for any improvement. However, if the flow rate is well below the rated capacity, then something must be restricting the flow. For the sake of comparison, my two, 2" diameter x 16" long lift cylinders fully cycled 4 times in 63 seconds when fed with a 3.5gpm pump at full throttle. If yours takes 20 seconds just to fully raise once, then either your cylinders are massive, or there is something wrong in the system.

Thanks, torch,
My cylinders are 2.5" x 30", I used the old 1001, 1002, 1003, method of counting seconds and to be fair when it warmed up it goes down to 15 seconds. The old front pump raised the bucket in about 10 seconds at around 2000 to 2500 RPMs, never did it at full throttle, I try to keep it working around that range when possible. I think the problem is the rear pump is just only 3.6 GMP.
I didn't crank the tractor with the pressure line unhooked, I just turned it over to see if the pump was pumping, which it was. I have blew out all the lines including the metal ones and am going to reinstall the new pump, plus cleaned out the controls. but found nothing blocking the fluid flow.
Thanks, torch.

 

[torch]

Wow. Big cylinders and a 30" stroke -- no wonder it's taking a while to go up!

Works out to 295cu in to extend both of them. Which is 1.277 USG. If it took 20 seconds, then that's 3.8 GPM out of the pump.

You don't mention the diameter of the rod, but let's assume 1-1/2" given the diameter of the piston. So it would take 242 cu in (1.048 USG) to retract the cylinders. A full cycle (up and down) would be 2.325 gallons. If the PTO pump is only capable of 3.6 GPM, you're going to be sitting darn near 40 seconds per cycle! And that's at full PTO speeds.

Yeah, I think I'd be trying to get the front pump working! Even if I had to rig a manual by-pass valve between the intake and discharge just for starting purposes.

 

[mllkn6]

Wow. Big cylinders and a 30" stroke -- no wonder it's taking a while to go up!

Works out to 295cu in to extend both of them. Which is 1.277 USG. If it took 20 seconds, then that's 3.8 GPM out of the pump.

You don't mention the diameter of the rod, but let's assume 1-1/2" given the diameter of the piston. So it would take 242 cu in (1.048 USG) to retract the cylinders. A full cycle (up and down) would be 2.325 gallons. If the PTO pump is only capable of 3.6 GPM, you're going to be sitting darn near 40 seconds per cycle! And that's at full PTO speeds.

Yeah, I think I'd be trying to get the front pump working! Even if I had to rig a manual by-pass valve between the intake and discharge just for starting purposes.

Torch, the rods are 1.5", now you know why I'm working to get the front pump going again. But it drops in 6 seconds which isn't so bad, the bucket works both ways in about 6 seconds also, just lifting is slow.

Here are a few pictures of the pump, bracket it fits in and shaft, you can see the 3 prong connector and the plastic spacer I glue in so it stays till I get it bolted up. You also can see where I had to cut the back of the frame out for the new pump.
From the frame to the connector on the motor is a hair shy of 8", the prongs have to be rotated so the go past the ones of the motor connector.



I was planning to hook it up today till I found out they are calling for rain moving in tonight till Sunday, so I had to get a few other things finished before the rain hits. But I need this pump working badly, the other way is just to slow.
Hopefully tomorrow I'll get it installed and try it out. It's a job holding that pump up to get the shaft through the hole so it can connect to the motor especially when you can't see the motor from the front of the tractor. I have get a couple of bolts started them go around to the drivers right side so I can see and feel the alignment of the connectors, if an adjustment has to be made have to unbolt it and make it, then do it all over again. Darn thing get heavy too. LOL
Once I get the pump connected, I'm going to attach the fill and pressure lines to the pump and put the other end in a bucket of fluid then try to start the tractor and make sure the pump is still pumping. If it works I'll connect them to the controls and reservoir and see if it works then too.
Thanks, Torch.

Don

 

[mllkn6]

Hi Guys,
Well I got good news and bad news.
We will start with the good news, I installed the pump, was going to test it with the pressure line not connected to the controls but that end in a bucket tp see if the pump was pumping and it was. My plan was to turn it over till something came out, but it had other ideas, it fired off as in running. Before I could cut it off, it had blown the bucket across the shop and was spraying fluid everywhere, it looked like a fire hose let loose. I cut it off.
I then put down some Stay dry solution to get up the fluid. Then I connected the pressure line to the controls and tried it again, again it fired off, but I had a leak on the outlet fitting coming off the pump so I fixed it. I fired it up again, no leak, and the lift and bucket works but slow.
I gave it more fuel to bring up the RPMs and the motor tried to do it but it stayed at 750 RPMs. It will not idle up above 750 RPMs, white smoke comes out of the stack and it shakes as it tried to make more power.
This really has me baffled, is it the pump or the controls or what. I'll make a short video.

 

[torch]

Well I guess that proves the pump is OK! <lol>

I believe something is severely restricting the flow.

I wonder if it is so restricted that it would give itself away with a localized temperature change after a short period of running? Or an intense noise concentrated at the restriction?

Normally, an open-circuit hydraulic system should have little or no pressure in the lines while the spool valves are in the neutral position. The pump simply circulates the fluid back to the reservoir. When a spool valve is operated, the return is closed off and the fluid redirected into a cylinder, where it can build pressure. At the same time, the opposite end of the cylinder is discharged back into the reservoir through the return line.

A restriction in either the supply or return lines will slow the system and load up the tractor. It could be in a hose, the spool valve set itself, the filter.

Does your system have any quick-disconnects in line? Maybe one has failed?

 

[mllkn6]

I made a 22 second video but it says it's to big to post, I don't know how to make it fit.
What could stall a 25 HP motor, could the relief valve be doing this? Could it be the controls as it's between the controls and the reservoir.

 

[mllkn6]

Well I guess that proves the pump is OK! <lol>

I believe something is severely restricting the flow.

I wonder if it is so restricted that it would give itself away with a localized temperature change after a short period of running? Or an intense noise concentrated at the restriction?

Normally, an open-circuit hydraulic system should have little or no pressure in the lines while the spool valves are in the neutral position. The pump simply circulates the fluid back to the reservoir. When a spool valve is operated, the return is closed off and the fluid redirected into a cylinder, where it can build pressure. At the same time, the opposite end of the cylinder is discharged back into the reservoir through the return line.

A restriction in either the supply or return lines will slow the system and load up the tractor. It could be in a hose, the spool valve set itself, the filter.

Does your system have any quick-disconnects in line? Maybe one has failed?

No quick connect in line.
The pump work fine, surprised me when it started up so quick, the leak was at the pump outlet fitting and it seemed to run better when it was leaking.
fixed it but it's still leaking there, fitting gone bad I guess or to much pressure.
That fitting is a 90 degree fitting, could it be bottlenecking the system? I got a long sweep 90 on after that out of pipe. The old system had the hose coming off the 90 and it dropped down to under the tractor about 6" and drug on anything under it. I put on a long sweep 1/2" pipe then connect to the hose. I thought it would flow better that way, the sweep is 12" long.
I can take temperature checks along the system as I have a temperature gun that reads the temperature, if needed.

 

[PoTreeBoy]

I can tell you I'm confused. Your tractor came with a hydraulic pump attached to the engine, around 3.5 GPM right? And the loader has its own pump? Does it connect to the PTO or to the crankshaft? Where does it draw fluid from - the gear case or an external tank? How do you switch the loader between the two? I'm lost. The original picture of the cracked pump doesn't look anything like the new pump to me. What are the specs on the new pump? Is it possible to run your bucket experiment (with everything tied down) and get a rough estimate of how much you're pumping - maybe 15 sec at 800 rpm?

 

[mllkn6]

I can tell you I'm confused. Your tractor came with a hydraulic pump attached to the engine, around 3.5 GPM right? And the loader has its own pump? Does it connect to the PTO or to the crankshaft? Where does it draw fluid from - the gear case or an external tank? How do you switch the loader between the two? I'm lost. The original picture of the cracked pump doesn't look anything like the new pump to me. What are the specs on the new pump? Is it possible to run your bucket experiment (with everything tied down) and get a rough estimate of how much you're pumping - maybe 15 sec at 800 rpm?

PoTreeBoy.
NO , my 1977 L 245DT came with a front 7.36 GPM pump connected to the engine by way of a shaft shown in the pictures, for the loader, the 3 point hitch has an internal pump of 3.5 GPM for it.
The front pump connects to the crankshaft and runs the loader only, which is 8" away from the pump that is why it needs a shaft to connect it.
There is a reservoir mounted on the side drivers right side post for the loader with the fluid for the loader and front pump. the loader and 3 point hitch are separate systems. I can switch the rear pump between the backhoe and the 3 point hitch by way of a box under the seat, both run off the rear pump.
NO, the old pump is obsolete now, Webster is no longer in business who made the old pump. I measure the gears in the old pump 1.9085" x .5" x 3.4430" which is 8.5CID which is 7.36 GPM and Bailey Engineers figured the pump size. Which is about the same as the new pump of .85 CID and 6.8 GPM, closest one they had to it.
IT's ok to be confused by all this, as I'm totally confused and have no idea what is happening either. Should have been a simple as removing one pump and installing another. Right? Wrong. LOL

 

[mllkn6]

torch,
This is after a 5 minute warm up course it wasn't completely cold either. the RPMs did move up to 1000 RPMs after a little time running on it's own, but I had the throttle opened up to about 1500 RPMs.
temperature results:
1. pump 217 degrees
2. 90 degree fitting @ pressure side outlet 156 degrees
3. 90 degree long sweep pipe pressure side 100 degrees
4. pressure hose at long sweep pipe 103 degrees
5. controls 143 degrees
6. hydraulic filter 212 degrees
7. Line from filter to reservoir 140 degrees
8. reservoir bottom 136 degrees
9. filler hose at reservoir outlet 126 degrees
10. filler hose at pump 100 degrees
Hope this helps.
The hydraulic filter is new and a NAPA filter, suppose to fit this tractor. Been buying NAPA for years.

 

[PoTreeBoy]

PoTreeBoy.
NO , my 1977 L 245DT came with a front 7.36 GPM pump connected to the engine by way of a shaft shown in the pictures, for the loader, the 3 point hitch has an internal pump of 3.5 GPM for it.
The front pump connects to the crankshaft and runs the loader only, which is 8" away from the pump that is why it needs a shaft to connect it.
There is a reservoir mounted on the side drivers right side post for the loader with the fluid for the loader and front pump. the loader and 3 point hitch are separate systems. I can switch the rear pump between the backhoe and the 3 point hitch by way of a box under the seat, both run off the rear pump.
NO, the old pump is obsolete now, Webster is no longer in business who made the old pump. I measure the gears in the old pump 1.9085" x .5" x 3.4430" which is 8.5CID which is 7.36 GPM and Bailey Engineers figured the pump size. Which is about the same as the new pump of .85 CID and 6.8 GPM, closest one they had to it.
IT's ok to be confused by all this, as I'm totally confused and have no idea what is happening either. Should have been a simple as removing one pump and installing another. Right? Wrong. LOL

I'll spare you my fountain of fluid story . So you've proved the pump-to-valve hose is clear. The return hose from the valve goes straight back to the reservoir, right? Take that hose off at the valve and try blowing air back to the reservoir - gently or you may have a geyser. If that hose is clear, there must be a blockage in the valve. You may need to post a picture of the valve - there doesn't seem to be a lot of info available.

 

[mllkn6]

I'll spare you my fountain of fluid story . So you've proved the pump-to-valve hose is clear. The return hose from the valve goes straight back to the reservoir, right? Take that hose off at the valve and try blowing air back to the reservoir - gently or you may have a geyser. If that hose is clear, there must be a blockage in the valve. You may need to post a picture of the valve - there doesn't seem to be a lot of info available.

PoTreeBoy,
I removed all hoses Monday and blew them out, I took the reservoir off and cleaned it out also before removing the hoses, I removed the filter and drained it out, nothing came out of it but fluid, I even removed the metal lines and blew them out. I took the controls apart and clean them also, if you referring to the relief valve, here are pictures of it on here also and the controls. Are you referring to the valve that holds the hydraulic filter? It was also blown out using my air compressor Monday also, nothing came out of anything as far as blockage.
I filled the reservoir with new fluid too. All the hose are brand new, less than a month old.
Could the filter be the wrong filter for this machine?
There is no information for the pump, controls, or the filter group at all. my tractor was made in Japan and shipped here already assembled, it was the 922st one brought to the US by Kubota according to the serial number, my serial number is 10922, they started at 10000. I bought it new in 1977 too, $10,000 with loader and backhoe. LOL
While waiting on the new pump to come in I changed all fluids and filters on the tractor about a month ago and bought new hydraulic line for the loader also.

 

[PoTreeBoy]

PoTreeBoy,
I removed all hoses Monday and blew them out, I took the reservoir off and cleaned it out also before removing the hoses, I removed the filter and drained it out, nothing came out of it but fluid, I even removed the metal lines and blew them out. I took the controls apart and clean them also, if you referring to the relief valve, here are pictures of it on here also and the controls. Are you referring to the valve that holds the hydraulic filter? It was also blown out using my air compressor Monday also, nothing came out of anything as far as blockage.
I filled the reservoir with new fluid too. All the hose are brand new, less than a month old.
Could the filter be the wrong filter for this machine?
There is no information for the pump, controls, or the filter group at all. my tractor was made in Japan and shipped here already assembled, it was the 922st one brought to the US by Kubota according to the serial number, my serial number is 10922, they started at 10000. I bought it new in 1977 too, $10,000 with loader and backhoe. LOL
While waiting on the new pump to come in I changed all fluids and filters on the tractor about a month ago and bought new hydraulic line for the loader also.

OK. I found a picture of an L245 for sale. Looks like the valve mounts on the tank. This one from Surplus Center should replace it for a little over $100 - https://www.surpluscenter.com/Featu...M-Chief-220907-DA-Hydraulic-Valve-9-12461.axd (fittings extra). If it was mine, I'd couple the inlet and outlet hoses and pump it around just to make double sure the problem is in the valve before buying a new one. I'm stubborn, but I eventually cry uncle (more so as I get old).

 

[Dave_eng]

How is the backhoe supplied with hydraulic power?

Is the backhoe on the tractor now?

Dave

 

[mllkn6]

.

How is the backhoe supplied with hydraulic power?

Is the backhoe on the tractor now?

Dave

Dave, the backhoe runs off the 3 point hitch pump by way of a box under the seat where the hydraulic lines plug in and I pull a lever to change over from the 3 point hitch to the backhoe. It's one or the other but not both at once, it's a separate system, that has the 3.5 GPM pump and how I have been running it the past few days, slow, the pump is internal and works off the transmission fluid. That is the system that took 20 seconds to raise the bucket.
NO, the backhoe isn't on the tractor now, but the bushog is, works off the 3 point hitch system.
Did you look at the temperatures I put on here?

 

[Dave_eng]

For a minute I thought I found the problem.

You wrote: 8.5CID which is 7.36 GPM and Bailey Engineers figured the pump size

When I plugged 8.5 and 2,500 rpm into a formula I go around 90 gpm. A very high flow!!!

Now I realize you meant .85 cid.

I cannot imagine the valve being the issue as the loader works when plumbed off the 3.5 gpm pump.

Were the temperatures measured when running the loader off the 3.5 gpm pump?

Where is the filter plumbed in the system. On the suction side of the pump or in the Return to Tank part of the circuit?

Could you upload your video to youtube and then post a link here?

Dave

 

[mllkn6]

For a minute I thought I found the problem.

You wrote: 8.5CID which is 7.36 GPM and Bailey Engineers figured the pump size

When I plugged 8.5 and 2,500 rpm into a formula I go around 90 gpm. A very high flow!!!

Now I realize you meant .85 cid.

I cannot imagine the valve being the issue as the loader works when plumbed off the 3.5 gpm pump.

Were the temperatures measured when running the loader off the 3.5 gpm pump?

Where is the filter plumbed in the system. On the suction side of the pump or in the Return to Tank part of the circuit?

Could you upload your video to youtube and then post a link here?

Dave

Sorry missed the decimal point, LOL Math and English were my worst foreign subjects in school, LOL.

The temperatures were taken off the front pump, the new one, 7.36 GMP. I have disconnected the 3.5 GPM pump of the 3 point hitch to get the front one going.
The filter is on the return side as it comes of the control valve. Here are a few pictures of it.

 

[mllkn6]

Thanks Dave,
Uploaded the vide to of the tractor running to You Tube, here is the link:

You can see how the tractor shakes the steering wheel when I take my hand off it, it even shook the phone in my hand as I was getting of the tractor and laid my arm on the lift post to get off while holding the phone to video.
I wanted to get a look at the shaft to make use it wasn't vibrating or wobbling is why I showed the connection between the two shafts, first time I got to see them running.
The leak is the fitting on the pressure side of the pump, maybe the fitting has gone bad or to much pressure as it's leaking when the fitting goes into the pump.

 

[Dave_eng]

Ok, watched the video.

My next suggestion is to connect the pump output hose (valve IN) to the return to tank hose thus completely eliminating the valve but testing the filter's ability to handle the flow as well as anything else on the return to Tank path.

With the return hose held on by a hose clamp it looks easy enough to do.

Can you crank the engine with the fuel shut off so it does not start before you are ready for the BIG test?

Dave

 

[mllkn6]

Ok, watched the video.

My next suggestion is to connect the pump output hose (valve IN) to the return to tank hose thus completely eliminating the valve but testing the filter's ability to handle the flow as well as anything else on the return to Tank path.

With the return hose held on by a hose clamp it looks easy enough to do.

Can you crank the engine with the fuel shut off so it does not start before you are ready for the BIG test?

Dave

OK Dave,
let me get this straight, take the pressure line from the pump off at the control valve and connect it to the filter inlet fitting, by passing the control valve completely, right?

yea, I can shut off the fuel to the motor, using the fuel shut of valve at the tank, then drain the fuel pump and then it will only turn over and not crank.