Hydraulics and FEL modification questions

[aardvark]

I just bought a BX23 service manual on ebay and received it Monday. I'll look through it to see if where the pressure relief valve is, and how it assembles. Perhaps the valve is an item I could buy from Kubota and dissassemble, to see where the shims would go. I imagine the relief valves must be pretty standard between the different Kubota models?

Can someone cross reference the BX relief valve part number to other relief valves on the larger machines? Perhaps there is already a kit marketed for the larger machines that would retrofit into a BX?

 

[aardvark]

I actually just called the Kubota parts dept but they could not break down the two different relief valves in a more specifc manner. The two valve assemblies are K2561-14960 andK2561-14970. They each use the same spring p/n 6C050-98290, the same check relief plug p/n K2561-14930, and the same O-ring p/n 6C050-98340. If anyone esle can break these numbers down, and specifically the relief valve numbers, I would appreciate it. I assume on relief valve is for the hydrostatic drive system, and the other valve is for the hydraulics and steering system. I have no idea which is which though.

 

[jim_wilson]

As part of the feasability study of this whole idea I went out this morning before I went to work and took a few pictures. I wanted to see if there was going to be clearance for attaching a cylinder to the FEL arm to bucket mounting brackets if the bucket was rolled all the way back. Then I wanted to see where the bucket ended up if was rolled all the way forward. When I got home tonite I pulled the pictures into Photoshop and did some quick hacking to try to come up with a picture of what I think might work here. The first picture shows the bucket rolled all the way back - in order to attach dual cylinders I would either have to somehow separate the existing arm pivot brackets from the bucket and make new ones ( I know these brackets are a standard size so I can get the steel easily) - or I would have to weld on an extension to the bracket to attach the end of the cylinder to so it would clear when the bucket was rolled all the way forward.
I have looked at a few different FEL quick attach setups on John Deere and Kubota tractors and the John Deere is the one that looks the easiest to duplicate. I also read thru a post from kennyd where he made a quick attach plow setup for his JD and the pin and hook pieces for the JD type are available. The Kubota quick attach has a cool lever that locks the lower part of the QA to the bucket - it is neat but looks hard to duplicate.
I think this can be done without moving the bucket any further out on it's pivot point. It can also be done with a minimum of steel so I wont be increasing the weight out at the end of the FEL arms by a significant amount. It looks like the biggest technical challenge is going to be finding the right size cylinders to use for the dual setup. If I have a chance this weekend I will take a trip to a few dealers and take some measurements of dual cylinder FEL's on JD2210, MFGC2300 and maybe some smaller B series Kubotas or New Holland's. That ought to give a good starting point.
Does anybody have recommendations on who manufactures quality hydraulic cylinders? If I could find a stock Kubota (or other tractor mfg.) cylinder that fit my needs would it be worth buying thru a dealer or would that cost way more $$$ than needed? I have Northern Tool and Surplus Center catalogs and I know there is a pretty good selection in both of them too.

 

[jim_wilson]

Picture (with Photoshop hack) showing bucket rolled all the way forward and imaginary bracket. For the upper mounting point for the cylinders I would add some steel mounting points similar to what the JD2210 and MFGC2300 do for their dual cylinder setups. I think if I did this I would just leave the bracketry for the center curl cylinder on the bucket. It would be a convenient place to mount a cylinder for a grapple hook cylinder if I ever chose to do so in the future.

 

[aardvark]

I looked through my BX23 service manual last night, and it says adding a 0.1 mm shim under the relief valve spring will increase system pressure by 39 psi. I estimated, without any real scientific calculations, that a 0.5 mm shim (about .020") will increase lift capacity of the loader to just over 500 lbs. A .063" inch shim should bring lift capacity to just over 600 lbs. I say "without any real scientific calculations" because I just used a simple ratio to generate these numbers. The physical geometry of the loader mechanics are more complex than a simple ratio. It looks as if the relief valve in question is the one located behind the left rear wheel. I haven't looked at the tractor yet, just the service manual. I don't know if I will do this, I probably won't. This is just info for anyone interested. I most likely will buy the pressure testing kit so see whether my relief valve is opening sooner or later than it should be though. Mostly just because I'm curious, at this point.

 

[jim_wilson]

If you find the pressure testing kit I would be interested in the part # and where you got it from. It would be interesting to see if the hydraulics in the tractor are really functioning where they should be. Shimming the relief valve to get a little more pressure out of it is something I might think about doing - but probably only by a little. I would like to know where the actual pressure is by testing it before making a modification like that though.
This weekend I am going to go visit a few tractor dealers and take a look at some dual cylinder FEL setups and maybe measure out the cylinder dimensions on a few so I have some idea of what type of cylinders I should be looking for. The specs on the B series Kubota FEL's are pretty close to what the BX is rated for so it may be that I could use cylinders from a B series FEL to make the dual cylinder setup for the BX. The research continues....

 

[Catmando]

If you use two cylinders instead of one then the diameter of the cylinders can be decreased. Considering that reduction in cylinder diameter you won't loose that much speed.

 

[cleatus]

Why not build a sub rack that uses all stock mounting points, then add lower brackets that would allow slide pins to attach original lower clevits, add u channl to top of bucket to catch 1/2" plate on top of sub rack. Would also be good place to hang forks off of old fork lift.

Here's simple drawing. This idea and measurment came from looking at a LA211 loader

 

[cleatus]

I forgot to mention that using sub rack would not move out piviot point. If u are worried about the 3" extenison buy more tractor. /forums/images/graemlins/shocked.gif /forums/images/graemlins/shocked.gif /forums/images/graemlins/confused.gif

 

[jim_wilson]

My original thoughts were to make something like you suggested. The problem is that in order to make the frame substantial enough to stand up to things like backdragging with the bucket and digging and stuff like that the frame has to be pretty substantial and then it starts to weigh a lot. I don't want to add any more weight to the FEL than I absolutely have to because I don't want to lower the lift capacity any more than I have to. My thought was that by going to the dual cylinders I actually end up with simpler setup in that the quick attach plates don't have to be that big and the dual cylinders probably won't weigh that much more than the single cylinder they are replacing. My guess is that the weight penalty for the dual cylinder setup might come in at 20 pounds - whereas the weight penalty for the single cylinder/large frame setup probably comes in around 65-75 pounds.