B1700 hydraulics died

[tbronson]

I have a B1700 HST 4WD with about 1300 hours on it. A couple of weeks ago, it started losing power when I'd first press the accelerator: the RPM would dip, the pedal felt soft, and then it would engage, the engine revved back up and things seemed normal. The loader and hitch seemed fine. Over a period of days, the problem gradually got worse, the engine would dip and sometimes even stall out when I first hit the accelerator to go forward or reverse, and the pedal at that first press felt soft, no resistance, then kind of stuttered. Then a big dip in RPM, sometimes a stall, started to happen as well when I put a load on the loader, like trying to raise a filled bucket from a dirt heap. I also noticed it was losing power/RPM when steering all the way to the right or left. Today, I started it, engaged, and when I pressed the accelerator, there was a kind of grinding/chukking sound, the pedal stuttered a bit, the tractor barely crawled forward, then stopped and refused to move. The loader and power steering now also don't respond.

Any idea what the problem is? It's over an hour's drive to my dealer - is there anything I can do to diagnose myself, or use local non-Kubota help to diagnose (I'm close to a fairly big town)?

Thanks!

 

[North Idaho Wolfman]

Have you checked the fluid level and quality?

After that I think your in pretty deep, the 2 things you are describing are seperate systems, The loader, steering and three point run off of an engine mounted pump, while the HST is it's own pump.

If you have lost both systems #1 thinking is something has broken up and plugged both the screen filter (feed for the hydralic pump) and the spin on filter (feed for the HST) and thus both are down.

 

[tbronson]

Have you checked the fluid level and quality?

After that I think your in pretty deep, the 2 things you are describing are seperate systems, The loader, steering and three point run off of an engine mounted pump, while the HST is it's own pump.

If you have lost both systems #1 thinking is something has broken up and plugged both the screen filter (feed for the hydralic pump) and the spin on filter (feed for the HST) and thus both are down.

Yes, the fluid level is fine and so should the quality. Any way to diagnose further for myself, before sending it off?

 

[North Idaho Wolfman]

If you've drained the fluid and changed both filters with no debris found then move on to the high pressure side of the system.

Have you cracked the high pressure line to see if your getting any flow from the Hydraulic pump?

Sorry but trying to even guess what's going on with the HST would require a lot more info and testing to give you any kind of good answer.

 

[tbronson]

If you've drained the fluid and changed both filters with no debris found then move on to the high pressure side of the system.

Have you cracked the high pressure line to see if your getting any flow from the Hydraulic pump?

Sorry but trying to even guess what's going on with the HST would require a lot more info and testing to give you any kind of good answer.

Cool, thanks! I'll drain and change filters, look for debris. That'll take 3-4 days, ordering parts Monday. Will also do a close inspection of all the lines

Not sure how to open the high pressure line, but I'll do the filters and checking first.

Two things happened with the hydraulic system recently that might have something to do with this.

1. About a year ago, while rototilling, something punctured the filter, a tiny hole, and fluid was spraying out. I replaced the filter, didn't drain, but topped it up. Things seemed to be fine for the rest of the year. I use it about 150 hours a year.

2. A couple of months ago, I noticed a slow leak in one of the rubber/flexible hydraulic lines, where it had rubbed against a bolt head. The drip was enough to make a small pool overnight, hard to tell how much because parked on dirt/grass. I temporarily fixed by making a sleeve of epoxy putty, wrapped with a piece of hose and clamped with a garden hose joiner. Topped up fluid. Ordered a new hose from Kubota, but haven't installed. The patch seemed to work, but there's a thin film of fluid on the hose for a couple inches below the patch, so not 100% sealed, but no drip and no noticeable loss in fluid level checking with dipper.

If that all sounds like a ridiculous way to keep things going, well, I guess I'm learning the hard way...

Thanks again.

 

[Daren Todd]

So, the rubber hydraulic line that got the pin hole. Was it one of the lines that goes to the hydraulic pump?

If so, it's most likely the intake line. If it has a small pin hole leak, it can cause the hydraulic pump to lose prime and take on air. Which if ran that way long enough, will cause the pump to fail.

Another thing that can happen on older hydraulic lines. They can rot internally, then have a piece of rubber seperate, and plug up the hydraulic filters, screens, and valves.

 

[North Idaho Wolfman]

Yep, Agree with Daren, pull and change the hose, suction leaks can be really hard on the system.
If you pull the filters and find debris, then stop, pull the pump next.

If you want to do the work yourself, get the WSM (Work Shop Manual / AKA Service manual) it will help with all the parts placement and testing.

 

[tbronson]

Really great advice! Already downloaded the WSM from the link in the sticky.

You've given me a solid starting point and idea of what's likely going on, and the WSM is like a lamp in the dark. I'll check/clean/change all the filters, screens, lines, replace the pinholed hose, change fluid and see where I am at that point. Will follow up here.

Thanks! Cheers!!

 

[tbronson]

The end to this story, not sure if it will help anyone else since I'm chalking this up to an unlucky (and expensive) fluke breakdown, but might as well be complete!

After the advice above, my next DIY step was removing the screen filter, a mesh tube a few inches long that was clogged with silver flakes, which is, I guess, the debris mentioned above. Called my local Kubota dealer, and they said that didn't sound good, something likely grinding up, tractor would likely have to be split to check things out, and that would be getting into up to 8-10 hours each way, taking apart and reassembling.

Next, got a recommendation for a local heavy truck mechanic who dropped by, checked things out, and guessed, with debris, was probably the hydraulics, and tractor would have to be split. He recommended the dealer as he wasn't familiar with Kubota, he could repair it but would likely cost him or me on getting up to speed with any Kubota specifics. A good conversation and concurring second opinion (after the dealer on the phone).

Floated off to dealer. Bottom line: the HST assembly was toast. Still looking into what that is exactly, but it has tiny pistons and whatnot, no individual parts available, and too expensive to rebuild in any case, they said. Some sort of fluid regulating input plate had stopped working properly, then tiny pistons had ground down, probably happened over 30 hours (that's the best I remember of the explanation, which was actually very clear at the time .

So, replaced HST assembly at $3700 CDN for the part, and 14 hours labor. Just over $5K total with tax. And they replaced the hose I'd patched. No other parts on the invoice, except a few seals, pins and and the like, mostly each around a buck, nothing over $15. I also asked for and got the broken unit back in a box.

From what the head mechanic explained, sounds like a fluke occurrence, not obviously attributable to any maintenance or misuse on my part, not common at 1500 hours, but it happens.

Thanks again for all the advice! I'm glad to have my little Kubota back - as long as it doesn't do something like that again in the next few thousand hours, I'm happy!

 

[Daren Todd]

Glad you got it fixed, and found out the issue But dang, at 5k to fix it, it must be a labor of love. At 5k to fix mine, that would be more then what I could sell it for as it sits now restored That baby would have been parted out, and the money I took in would go towards a new to me tractor

 

[tbronson]

... dang, at 5k to fix it, it must be a labor of love. At 5k to fix mine, that would be more then what I could sell it for as it sits now restored That baby would have been parted out, and the money I took in would go towards a new to me tractor

Haha, not a labor of love, a necessity. I use it more or less daily for one thing or another on a two-acre market garden that's set up for it, and I plant and re-plant all season - with a loader and 48" tiller, I can till and dump compost on single 5' wide beds, getting in and out from 14' main paths. I looked around a bit, and seems like at least 10-15k for an equivalent used machine. So I gambled on, with only 1500 hours, this is a one-time big repair for the next while. I look at it like I got a used machine for 5K, checked out by the dealer, instead of hunting for a replacement in the middle of the growing year.

How much could you get for parts, and how long and how much work could that take? I didn't consider that, so it would be good to know for next time...!