Hi guys, I know my Tractor and loader are obsolete. It's been a great machine since I purchased new in 1993. 2430 hrs later, An unusual thing happened in this last snow. I rolled toward the snow pile with the boom up and bucket dumping a load. The tractor slid into the snow pile with the bucket at full dump position. Not real hard or anything real unusual but.... at high rpm, the bucket did not want to curl back? It was moving to curl position very slowly and straining the pump. all other functions are normal. After a full curl back, at idle the bucket tilts forward and curls back smoothly. raise the rpm's and it strains to curl back again? I reversed the bucket lines and it seems to move smoothly. It's a but odd to see it operate in reverse and since the loader valve has the "speed dump" feature. (Regen?) Anyhow, today was nearly 40 degrees and I tee'd a 3000psi pressure gauge on the lower bucket cylinder hose. (the curl) and when straining to return I saw about 1600 psi. I then decided to swap the hoses on the valve right to left and let the boom spool power the bucket cylinders and the bucket spool power the boom. this worked fairly well but so backward. I actually loaded a bunch of snow this way and got the hang of it. The cylinders seemed to function normally leading me to believe the valve is at fault. when I returned home, I swapped the hoses back to normal and the trouble returned. At any rate, I understand that an aftermarket valve is in order and I need to decide regen or no regen (speed dump). I dont mind this swap but I really would like to know what went wrong all of a sudden? Hoses are new, fluid level correct and was changed about 100 hours ago. any idea what failed in the valve block? linkages are tight and spools move and detent as they should. strange one for sure. I would appreciate any insight. thanks so much.
B2150 / LA350 loader valve function diagnostic help please
- Thread starter walkerheaders
- Start date
Paging @TheOldHokie. In the meantime, could you post a picture of the bottom of your valve? The end opposite where the spools come out. I've recently discovered that some Kubota loaders with regen have 3 positions and some have 4. This might help figure out your issue.
Does the boom circuit still function correctly? The way you described the occurrence, I'm inclined to suspect damage to the pivot or one or both cylinders, although some of the things you tried might not support this.
Can you confirm that the bucket can dump and curl easily with the cylinders disconnected? There may be a stop that got bent, but probably the cylinders limit the dump travel.
I'll stop here in case TOH has checked in.
Does the boom circuit still function correctly? The way you described the occurrence, I'm inclined to suspect damage to the pivot or one or both cylinders, although some of the things you tried might not support this.
Can you confirm that the bucket can dump and curl easily with the cylinders disconnected? There may be a stop that got bent, but probably the cylinders limit the dump travel.
I'll stop here in case TOH has checked in.
whitetiger
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Replace the tips and couplers on your bucket hoses. You have at least one set that is not fully opening, which is restricting oil flow.
Let's check the valve function.
Disconnect the hoses from both ends of one cylinder and put them in a bucket where you can observe the flow.
Start the tractor and run at idle. Push the lever to curl the bucket. You should get flow out of one hose. Push the lever to dump. You may get flow out of the other hose, or both hoses. If you have a 4 position valve you may get different behavior depending on whether you move the dump side a little or full stroke. If you have a 3 position valve, you should get flow out of both hoses.
Try this and let's go from here.
Disconnect the hoses from both ends of one cylinder and put them in a bucket where you can observe the flow.
Start the tractor and run at idle. Push the lever to curl the bucket. You should get flow out of one hose. Push the lever to dump. You may get flow out of the other hose, or both hoses. If you have a 4 position valve you may get different behavior depending on whether you move the dump side a little or full stroke. If you have a 3 position valve, you should get flow out of both hoses.
Try this and let's go from here.
If the dump spool is regenerative you cannot reverse the bucket hoses. It simply wont work. Put them bsck in the proper locations.
Then do sime testing before condemning the valve. I doubt its the problem.
Dan
Thanks, I can try this when get home. I'm puzzled or sure. happened all of a sudden. I will check the dump hoses as well, then proceed. I do appreciate the help.
Thanks sir, I'll d more testing when I get home. loaded a bunch of snow with the hose reversed. strange to operate bu it worked well. I was surprised and puzzled.
If the boom operation is OK leave that circuit/spool alone and test the bucket. Its a simple circuit and easy to test. I would focus on the couplers per @whitetiger. A simple test procedure would be
- Label and remove both coupker sets and plumb the hoses straight to the valve. If the problem is eliminated you know its coupler related.
- Put one set back and test again. If the problem returns you have a culprit.
- Remove the defective set and test the other to make sure you dont have two bad sets
Thanks so much sir, (Dan if I may call you) I value everyones reply and it gives me a lot to check. Going to be a few days before I can get to it.
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here's what NOT to buy. sure enough was the problem. Guys, I really appreciate your help. It was finally above 30 degrees today so I could get the tractor outside for a good hard look. I replaced one connector that looked like it was not seating correctly. this was on the dump line. I could blow thru it easy one direction.... not so easy the other direction. I'm guessing the return fluid while curling had too much resistance. I put one of my old leaky connector assemblies on and it worked great for about an hour. THEN, the boom up started acting up and stalling. these connectors even though fairly new....JUNK. Can anyone help identify my old ones? I'll be happy to get new versions of the same. OR... can we suggest a 1/4P tapered (female on both ends) connector assemblies (four) that we KNOW are good? Thanks again for pointing me where to look. this explains to me how it failed "all of a sudden"
here's what NOT to buy. sure enough was the problem. Guys, I really appreciate your help. It was finally above 30 degrees today so I could get the tractor outside for a good hard look. I replaced one connector that looked like it was not seating correctly. this was on the dump line. I could blow thru it easy one direction.... not so easy the other direction. I'm guessing the return fluid while curling had too much resistance. I put one of my old leaky connector assemblies on and it worked great for about an hour. THEN, the boom up started acting up and stalling. these connectors even though fairly new....JUNK. Can anyone help identify my old ones? I'll be happy to get new versions of the same. OR... can we suggest a 1/4P tapered (female on both ends) connector assemblies (four) that we KNOW are good? Thanks again for pointing me where to look. this explains to me how it failed "all of a sudden"
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It seems unlikely your new couplers hsve gone south. Before blindly throwing more parts at it test the circuit. Its simple and definitive. If you want guidance on how to do thst just ask.
Dan
I would certainly like to learn how to test the circuit if you dont mind sharing. I do in fact see a valve problem with one of my new connectors. As a test, I swapped in a set of the original connectors on the bucket circuit then moved a few tons of snow at high rpm's with no issues until the boom lift started giving trouble. I wanted to simply hook the hoses up direct as a test but need a few 1/4P couplers to get that done. I was thinking of you members and my reply while working. I'm always willing to learn how to diagnose a problem. I went to General Motors school in Fairfax Va. for automobile diagnostics when I was a young Chevrolet Technician in the 80's. Transmission rebuilding and racecar chassis fabrication then military robotics since 2002. It's frustrating to get beat by a simple system. So, I very much appreciate the help.
Lets start with a simple and clear statement of what does not work.
Does the boom raise and lower correctly?
P
Dan
Thanks sir, the boom stopped lifting out in the field after about half hour. Then I got it back in barn let it down and it started raising again like normal? I've never seen that before
Hmmmm. Intermittent sucks.
Do you have the WSM for the loader? Newer Kubota loader valves are "unconventional" so it would be helpful to know exactly how yours operates
Do you have rear remotes or a third function on the loader?
Any other hydraulic outlets like a backhoe or log splitter?
Lets try something simple first. Start the tractor, put the 3pt control in the full down position and test the boom. If it works as it should raise the 3pt to the very top and test the boom again.
Dan
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Thanks Dan, I'll try this when I get home from work. I appreciate your help. Those functions were working when I parked it. honestly, the boom function was never a problem until yesterday. then it started working again. problem or not, I do not trust the cheap connectors I put on it. my originals work but leak so I ordered a nice new set from Summit last night.
What are "those functions"?
The only function we are diagnosing is the boom on the loader.
Dan
When I parked the tractor, the boom up was functioning as well as the dump, curl and boom down. he boom did stop raising which made me pull the snow out by hand and back it into the garage. when I felt it safe to lower the boom, It did. then, I tried and it raised? dump and curl were working as well. Curl back was the original problem. thanks for staying with me. It is confusing,
The key to eliminating confusion is to focus on one thing at a time. Your last priblem was the boom so thats what we look at first.
So when you get home lets do the 3pt test to eliminate it as a potential source of interference with the boom function on the loader. Testing it is simple and fast. If thats not the problem we move to the next possibilty.
So please - in order to know where to go next do you have any rear remotes or a third function on the loader? Knowing whats in the circuit is crucial to an orderly trouble shooting process.
Dan
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