B26 Hydraulics fine, but won't move (much).

[galstaf]

Hey all,

I have a 2015 Kubota B26 that just stopped moving (mostly). It will move a bit.. better forwards than backwards.
It is extremely weak in both directions (forwards and back), and makes a very loud whining noise with a lot of vibration.

If the reverse stops responding altogether, it can help to push forward then reverse if that gives anyone a clue.

I didn't change anything.. the machine ran normally, then just got worse and worse over the course of a day until now it can barely move forwards or back.
Checked the hydraulic fluid levels and they are fine. I even topped it up with Kubota SUDT2, and it just threw out the excess all over the back of the machine.

The FEL and BH both work normally and are still plenty strong.

Can anyone help?

Thanks in advance for any help!

 

[D2Cat]

It sounds like your clutch has given up.

 

[lugbolt]

B26 doesn't have a clutch.

Could be a lot of things from a failed disk (drive flange that is "similar" to a clutch disk-but no clutch is involved, it just bolts to the flywheel and has splines in the middle) to failed HST to broken axle, etc. Very hard to diagnose things like this over the 'net. Similar to calling doctor saying "I don't feel good, what's wrong with me?"

 

[galstaf]

B26 doesn't have a clutch.

Could be a lot of things from a failed disk (drive flange that is "similar" to a clutch disk-but no clutch is involved, it just bolts to the flywheel and has splines in the middle) to failed HST to broken axle, etc. Very hard to diagnose things like this over the 'net. Similar to calling doctor saying "I don't feel good, what's wrong with me?"

Understood. But as I said, it is still able to move.. just very slowly and very whiney.. so obviously can't be a broken axle.
The rest of the hydraulics are still plenty strong.
I don't exactly know how the HST works, but would a failed disk cause this weak performance, or would it be completely dead?

 

[SAITCHO]

Have you checked the mechanical linkage of the HST pedal below the floor.

 

[galstaf]

Have you checked the mechanical linkage of the HST pedal below the floor.

Could you elaborate? what would I look for?

The linkage is obviously working a bit as it does move a bit. But obviously something is making it super weak.
Anyone else got any ideas?

 

[North Idaho Wolfman]

If the splines on the shaft or disk are stripped it will turn some, but will slip and not have power.

And the HST is a completely separate hydraulic pump, than the pump for the hydraulics off anything else like the FEL or the three point or BH.

 

[CurtisC]

Does performance get better after oil has warmed up? How many hours on the machine, what brand of hydraulic filters are you using, and how recent since they were changed? The B26 does not have a separate pump for HST, it has one 2 stage pump. There's one stage for power steering and the second powers everything else. My B26 developed excessive whining (but not vibration), sluggish cold weather hydraulic performance and would even stall under very cold conditions, the issue turned out to be bad WIX filters. Not saying all WIX filters are bad but after replacing both the hydraulic and HST filters with Kubota filters things are back to normal (still waiting on winter to confirm all's good in cold weather). Even if you've got Kubota filters its possible you got a bad one and you might want to consider changing them, particularly if you're getting close to their service interval.
Air leaks into return line can cause pump cavitation, whining and poor hydraulic performance. Check the return line and all fittings from tank to pump for cracks or splits. The rubber elbow at the pump is the weakest link and rather than spend a lot of time trying to inspect it for nearly invisible crack lines on the machine I just changed mine. Turned out not to be the culprit - but I was able to rule out one possible cause without spending a fortune.
The excessive vibration and forward / reverse thing doesn't sound good and tends to point towards the transmission but might as well rule out the cheap fixes first.

 

[galstaf]

Does performance get better after oil has warmed up? How many hours on the machine, what brand of hydraulic filters are you using, and how recent since they were changed? The B26 does not have a separate pump for HST, it has one 2 stage pump. There's one stage for power steering and the second powers everything else. My B26 developed excessive whining (but not vibration), sluggish cold weather hydraulic performance and would even stall under very cold conditions, the issue turned out to be bad WIX filters. Not saying all WIX filters are bad but after replacing both the hydraulic and HST filters with Kubota filters things are back to normal (still waiting on winter to confirm all's good in cold weather). Even if you've got Kubota filters its possible you got a bad one and you might want to consider changing them, particularly if you're getting close to their service interval.
Air leaks into return line can cause pump cavitation, whining and poor hydraulic performance. Check the return line and all fittings from tank to pump for cracks or splits. The rubber elbow at the pump is the weakest link and rather than spend a lot of time trying to inspect it for nearly invisible crack lines on the machine I just changed mine. Turned out not to be the culprit - but I was able to rule out one possible cause without spending a fortune.
The excessive vibration and forward / reverse thing doesn't sound good and tends to point towards the transmission but might as well rule out the cheap fixes first.

Thanks Curtis... From what I have been reading, I am looking at the filter also. This machine doesn't have the mesh screen that seems to be an issue on some of the other models, right?
So just the HST cartridge filter?


Could you take a picture of where you had the cracks on yours? I want to check to see if that isn't an issue also.

Thanks again!!

 

[galstaf]

Any recommendations of where to get the filters online with decent prices and shipping?

 

[CurtisC]

Thanks Curtis... From what I have been reading, I am looking at the filter also. This machine doesn't have the mesh screen that seems to be an issue on some of the other models, right?
So just the HST cartridge filter?


Could you take a picture of where you had the cracks on yours? I want to check to see if that isn't an issue also.

Thanks again!!

galstaf,
There's no mesh screen but there are 2 filters, the Hydraulic filter mounted on the right side of the tank and the HST filter mounted on the left side of the transmission. I'd definitely replace both, the Hydraulic filter is my bet on which was giving me trouble since its before the pump but since I changed them both together I'll never know. As mentioned before, don't waste your time with anything other than Kubota filters. As far as cracks, the return line looked good and the rubber 90 at the pump looked OK. Since you have to pull it to inspect it and given a new elbow is not that expensive, you might as well put a new one back in. Good luck!

 

[galstaf]

Re: B26 Hydraulics fine, but transmission won't move (much).
Update:
Success! Machine is up and working like a champ now!

In case anyone needs help with this... I looked again at the short rubber hose and can see it split because the hard suction pipe is slightly out of line and puts pressure on the hose. The split occurred at the point the hard pipe stopped and created a stress concentration.

To remove the hose:
Take off the throttle cable and the bracket it mounts to.
Remove the power steering feeder pipe
Remove the flywheel housing bolt nearest the rubber hose.
Remove the clamps holding the feeder and suction pipes together. This gives enough play in the suction pipe to move it out of the rubber hose without having to loosen the other end.
Remove the power cable from the fuel cut off solenoid.
Remove the hose clamps and take off the hose.



I didn't want to wait for parts shipping again by ordering a new hose as the filter pack came in today, so I repaired it instead. The repair also makes the hose a lot more resilient so it shouldn't fail the same way again. I used a 45 degree copper water pipe street elbow which fits perfectly down that piece of hose. (bought at Ace hardware).

The street elbow changes diameter half way thru (obviously), so I cut off the larger diameter piece with a grinder. This created an inch long piece of pipe with a slight elbow that worked perfectly with the rubber hose. I put teflon paste over the pipe and pushed it inside the rubber hose then put a hose clamp over the hole to lock and seal the split in the hose.

I put everything back and tested .. no leaks!

As my hydraulic filters came today too and the wheels were already removed to give me access room, I replaced the suction and HST filters.

Use the vacuum cleaner trick.. Even tilting the machine dramatically doesn't stop the hydraulic fluid pissing out. I lost a gallon of fluid from the suction filter in less than 30 seconds.
I put the vacuum on for the filler for the HST filter change and it only dripped a couple of ounces of fluid.

Put the wheels back on and ran it and bled out the air by rotation the steering wheel. Runs excellently now.. super responsive and plenty strong.

Thanks again everyone for all the suggestions .. and especially the service manual!

 

[CurtisC]

Re: B26 Hydraulics fine, but transmission won't move (much).
Update:
Success! Machine is up and working like a champ now!

In case anyone needs help with this... I looked again at the short rubber hose and can see it split because the hard suction pipe is slightly out of line and puts pressure on the hose. The split occurred at the point the hard pipe stopped and created a stress concentration.

To remove the hose:
Take off the throttle cable and the bracket it mounts to.
Remove the power steering feeder pipe
Remove the flywheel housing bolt nearest the rubber hose.
Remove the clamps holding the feeder and suction pipes together. This gives enough play in the suction pipe to move it out of the rubber hose without having to loosen the other end.
Remove the power cable from the fuel cut off solenoid.
Remove the hose clamps and take off the hose.



I didn't want to wait for parts shipping again by ordering a new hose as the filter pack came in today, so I repaired it instead. The repair also makes the hose a lot more resilient so it shouldn't fail the same way again. I used a 45 degree copper water pipe street elbow which fits perfectly down that piece of hose. (bought at Ace hardware).

The street elbow changes diameter half way thru (obviously), so I cut off the larger diameter piece with a grinder. This created an inch long piece of pipe with a slight elbow that worked perfectly with the rubber hose. I put teflon paste over the pipe and pushed it inside the rubber hose then put a hose clamp over the hole to lock and seal the split in the hose.

I put everything back and tested .. no leaks!

As my hydraulic filters came today too and the wheels were already removed to give me access room, I replaced the suction and HST filters.

Use the vacuum cleaner trick.. Even tilting the machine dramatically doesn't stop the hydraulic fluid pissing out. I lost a gallon of fluid from the suction filter in less than 30 seconds.
I put the vacuum on for the filler for the HST filter change and it only dripped a couple of ounces of fluid.

Put the wheels back on and ran it and bled out the air by rotation the steering wheel. Runs excellently now.. super responsive and plenty strong.

Thanks again everyone for all the suggestions .. and especially the service manual!

galstaf, Glad you found and resolved the issue, however one of the purposes of the rubber elbow is to help uncouple the suction hardline from engine vibration. Depending on the age of your tractor the old elbow part number (32741-39150 HOSE SUCTION) has been superseded once if not twice which generally means they changed something - usually (but not always) for the better. The repair, if I understand it correctly, makes half of the original elbow more rigid (ie clamped to the inserted piece of copper). Since the elbow has already failed once, the insert may ultimately accelerate failure in the rest of the elbow particularly where the copper insert ends in the middle of the bend or where it is clamped. I'd also be leery of any sloughing of Teflon paste into the pump. While I can't imagine that would cause pump failure I'd rather invest the $15-20 in a new elbow than worry about a $900 pump or having to deal with another leak. Just my two cents.....

 

[galstaf]

galstaf, Glad you found and resolved the issue, however one of the purposes of the rubber elbow is to help uncouple the suction hardline from engine vibration. Depending on the age of your tractor the old elbow part number (32741-39150 HOSE SUCTION) has been superseded once if not twice which generally means they changed something - usually (but not always) for the better. The repair, if I understand it correctly, makes half of the original elbow more rigid (ie clamped to the inserted piece of copper). Since the elbow has already failed once, the insert may ultimately accelerate failure in the rest of the elbow particularly where the copper insert ends in the middle of the bend or where it is clamped. I'd also be leery of any sloughing of Teflon paste into the pump. While I can't imagine that would cause pump failure I'd rather invest the $15-20 in a new elbow than worry about a $900 pump or having to deal with another leak. Just my two cents.....

Follow up for anyone with the same issue. Had the boot fail again and it causes some WEIRD symptoms.
I guess it was causing air pockets that would cause the machine to random run terribly then inevitably stall and be super hard to restart when hot.

I thought it could be an injector pump issue, fuel pump issue, blocked fuel filter or fuel line.

Turns out to be that damn suction boot again! I only figured it out as it wouldn't move again.
Ordered the new boot .. but top tip is to just wrap it in (good quality) duct tape and it will get your machine running again until you can get parts in.

 

[PaulL]

Duct tape for the win. Macgyver would be proud.

I presume it won't last long though, I think tape and hydraulic fluid don't mix well.

 

[Smokeydog]

Kubota now has an improved suction line that hopefully solves the problem with that pesky elbow from cracking. Takes the strain off the elbow.

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