Kubota B2630 loader hydraulics issue

[alaskatgc]

I initially posted this on the Kubota Owning/Operating list. Thought maybe the Hydraulics list might tap more experience.

My tractor is a Kubota B2630, loader LA403, total package has 130 hours, I bought it new about 2 years ago. Two weeks ago, while moving snow, I dumped a load in the ditch and that was it. The bucket was in full dump and no curl function was there. Moving the lever into curl position produced no movement in the bucket. If I held the lever in curl position and dragged the bucket backwards, it would come back to horizontal (while on the ground), but as soon as I raised the boom, the bucket would just dangle loosely. It remained freely dangling until I moved the lever to dump and the hydraulics would then catch the bucket and force it to full dump, per normal dump operation.

I took the bucket operating valve apart this past weekend and everything is clean as a whistle and the check valve has full contact all around (based on the shiney wear circle). I saw no issues in the valve at all. I now suspect one of the hydraulic cylinders has failed, although I don't know enough about them to know if a cylinder can fail in one direction only. The bucket cylinders on this tractor are 2-way...performing both dump and curl, depending on the valve position.

At this point, I guess I need to isolate one cylinder at time, using plugs in the two supply lines feeding each cylinder.

One additional piece of info on my particular tractor. Ever since I got it, I have noticed an annoying leak-down on the bucket. I continually had to trim the bucket to keep it from eventually sagging all the way to dump.

Does anybody have any thoughts and/or suggestions to offer?

Tom Carson
B2630 TLB
Juneau, Alaska

 

[Wayne County Hose]

Hello Tom,

Good details, makes life for us easier. Anyway, my thoughts is that the piston came off the rod in one of your curl cylinders. Easy to isolate. Remove the rod eye from the bucket and see if you can move the rod in and out of the cylinder. Keep the hoses and everything else attached. This will also isolate the faulty cylinder. Just a safety measure, make sure there is no pressure on the curl cylinders when you disconnect the end, hydraulic or mechanical.
Welcome to TBN. I hope this helps. BTW, how's the fishing up there?
Andy

 

[alaskatgc]

Andy,

Thanks for the input. I'll perform the check you suggest. Nice and simple, I like it! Unfortunately, I'm pretty busy for a couple of days...getting home late and leaving early in the morning. This check may have to wait for the weekend.

Fishing promises to be good this year. King salmon typically run in May, then Halibut all summer, and in August/September, Silver Salmon. I'm going to do my best to spend some time out in the boat this summer.

Tom

 

[alaskatgc]

Andy was right. The nut holding the piston on the shaft in one of my bucket cylinders had been forced off the threads. It looked like a manufacturing issue because the threads on the shaft were galled even where the nut hadn't touched them. Anyway, I bought a new nut, removed the seal and O-ring on the piston, welded the nut onto the shaft, reinstalled the O-ring and seal, and all is well.

Except...

I pulled the other bucket cylinder to inspect it as well. The nut and shaft are fine on that one, but the seal is not. It is stretched thin in one or two places, which is undoubtedly the cause of my annoying leak down when using the loader bucket.

I need to replace the seal and I'll do both cylinders as long as I'm at it.

Is there a site where I can identify the part number for the seals...and a good source for new seals?

This whole event sort of annoys me. This tractor is 2 years old with all of 124 hours on it. Sure doesn't seem like these issues should be arising.