Loader Custom made hydraulic pump attachemnt?

[Skurfer]

I recently purchased a Kubota L225DT (late 70's 4WD) that has a FEL. Apparently I am finding that is unusual for this tractor. The loader is a L1200 Kubota, but I have been told by a seasoned tractor enthusiast that often times there were kits or a backyard mechanic might make his own parts to put it all together.

Well the FEL didn't lift so I started tearing into it last week with my neighbor (the tractor enthusiast) who knows ALOT more about this stuff than I ever will.

What we found first was a broken keyway, great easy .59 cent fix, got the keyway in put back together and the loader worked...but it was spitting out hydraulic fluid through the seal in the pump. Took it apart again and found the connection from the crankshaft to the pump was backyard machined (e.g. not precision) on the shaft coming off the spline had too much slop. When we took it apart the keyway was bent and just about ready to break as well.

So now I need to find a new (improved way) to connect the hydraulic pump (which I will have to have the seals replaced) to the spline coming from the crankshaft. The original setup was a little odd (I thought), using a pair of gears with a double chain for the connection to the pump.

I can go into more detail if anyone has any input for me. Thought I would take the whole thing to a hydraulic shop in the area that also does machine work and maybe they can redesign a connection that will last.

Any input would be helpful.

Thanks

 

[638]

Chain couplings have been around for years. What you are calling gears are really chain sprockets, and need to be very well aligned & oiled occasionly. A keyway is the grove that is cut into the shaft and accepts the 'key' (square piece of steel). Not sure how your pump is mounted, a picture might help. Are you saying the shaft off of the engine is splined (mutiplegrooves in the shaft)?

 

[Skurfer]

Thanks for getting back to me,
Yup you are right those are sprockets not gears, I should have known that.

Do you know the reason for this setup? Does it increase the torgue to the pump? Seems unnessary otherwise, but there must be a reason.

wondering if a ujoint setup would work better. I can seen the distance would be critical and centering of the pump mount and the spline.

The first image is the pieces laid out on plywood. The next is the connection to the shaft coming out of the crank shaft (yes it is splined) The third might be confusing becuase that is a piece of plywood next to the sprocket, the rest had been removed when the picture was taken.

 

[638]

That's not really a bad setup providing the shafts are a close fit on the coupling bores, and everything is mounted solid. If I were setting up this pump, I would be looking at two chain couplings, one at the pump, the other at the engine shaft to allow for misalignment. If the engine is on rubber mounts, it will shake around quite a bit at times. Very hard on the pump and coupling the way you are set up. Is the engine side of the coupling splined or just a plain bored hole? I have seen plain bored couplings on a splined shaft with multible set screws into the splines to drive the coupling. But, it needs to be a very close fit to avoid excessive vibration. If the pump seal was leaking badly, I would guess poor alignment of the shafts and/or excessive vibration. If the seal is bad then the bearings may be bad also.

 

[rScotty]

Sure. As others have said, that is a very common way to hook two different types of shafts together. It has no other benefit, but the ability to match oddball shafts is benefit enough. From places like McMaster-Carr, you can order a sprocket for either sideto fit a wide variety of splines, keys, or shaft diameters. The sprockets themselves are just the hook-together mechanism. That is, the chain simply holds the two sprockets together and allows for a bit of mismatch and shake between the two so they don't have to be so accurate. There is no gearing or mechanical advantage. It is just a connector. In concept it isn't all that difference from connecting two broomsticks end to end with a piece of garden hose and two hose clamps. Just way stronger.

Most always the seals leak because the bearings have gone bad. And that eats up the teeth on the gears inside the pump. This is a replaceable part with a long but limited life and it is time to retire that pump. Rebuilding costs as much as a new one. These accessory pumps are common replacement parts and are probably not Kubota parts. Most are US made or can be replaced with a standard pump. (McMaster-Carr again) Just look at yours, measure the shaft, the mounting bolt pattern, and the inlet/outlet port size - by the way, I bet the ports will be good old NPT thread. Buy a similar model pump and stay within 25% of the flow rate. Bottom line is you need a new pump and a new chain coupling. Do that, and it won't take an hour to have your machine back into service. And it will last for decades.
good luck, rScotty

 

[Skurfer]

Great advice guys, thanks. I am limited in my experience in mechanics and its great to hear your thoughts. I ended up taking the whole setup to a machine shop nearby and they basically said the same thing. The pump is shot or not worth fixing considering a new one is about the same.

He is figuring a $200-300 for making a new pieces running from the crankshaft to the pump and said he would take a look at what he can find for a new pump as well. My gut says I will be inot this $500-700 for the new pump and shafts, sprockets etc. Hopefully I will not be too far off.

It sounds like from what Scotty was saying I could get these parts off the shelf and probably save half of that, but I have limited time I can spend on this. I also do not expect to be using the loader (or the tractor for that matter) more than a half dozen times a year, but I understand once you have one you will find all sorts of uses you never thought of before.

My motivation for getting the tractor was to launch my boat, but I am also like to work on these types of projects (did the same thing with my boat, replaced the transom, stringers, floor, etc).

So now I am planning on cleaning it up, new paint, and it will be basically a weekend tractor, not really a hard working tractor.

One more question - would you know if the shaft (that has been splined) coming from the crankshaft is removable with out opening the engine? The groves on the splined shaft are mostly gone either through rust or wear and tear. The machine shop says there is not enough on the piece i gave him to determine the shaft size. So this weekend I am going to take the belt pulley off and see if I can remove the splined shaft. If I can't remove this (without opening the engine) then not sure what my options are.

I understand you can put a pump on the PTO and run hoses up to the loader controls, but I would rather not do this. But if I have to open the engine to replace the shaft, I probably would rather use the PTO.

 

[638]

Looking closely at your #2 picture, it appears that the pulley is held on by a large nut. My guess is that the splined end is part of the crankshaft. Look up a parts list for your tractor. Should show the crank and pulley parts.

 

[Skurfer]

Great idea, didn't even think about looking for a parts list...tried searching for it and what do you know found Messicks web site and was able to get an engine parts diagram diagram with in a few minutes.

Unfortunately I think you are right about the shaft being all part of the crank shaft and being one piece. I am thinking now that since there are still some good shaft and spline available, maybe either cutting off an incn of so of the shart where the splines are worn so the new piece can get some good material (of course the new piece would have to be longer then), or maybe a spot weld would suffice or both.

 

[638]

Well, what have you decided to do? We always are interested in the outcome of a problem...

 

[Leejohn]

Skurfer I have the loader and the tractor parts manual if you want. I well have to email them to you, they are over the 1000kb for uploading.