NX5510 - No hydraulics after filter and fluid change

[Robin Veerman]

Years ago I had a Troybilt lawn tractor with an HST transmission. When I changed the oil, several times, I would insert a clear fuel line into the reservoir right down into the transmission before refilling it. As I poured the oil into the reservoir, not into the fuel line but alongside it, the air would vent out the line. I would continue to pull up the line allowing the air to vent until the oil level was correct.
Worked perfectly.

 

[Username Taken]

Years ago I had a Troybilt lawn tractor with an HST transmission. When I changed the oil, several times, I would insert a clear fuel line into the reservoir right down into the transmission before refilling it. As I poured the oil into the reservoir, not into the fuel line but alongside it, the air would vent out the line. I would continue to pull up the line allowing the air to vent until the oil level was correct.
Worked perfectly.

I believe my tractor has a hydraulic vent. Maybe called a self-purging setup??

I know because I found a few drops of oil under the 3-pt and wondered what was going on. Looked it up and sure enough.... a vent for the hydraulic system.

I'm sure that's the first place the OP checked. I think it's got a screen. Maybe a check valve. Don't know.

Makes sense that if it's cavitating, there's got to be air in the system. Why doesn't it vent out??

Only other thing is it's too low on fluid; and the OP has ruled that out. Or -- The air in the system is displacing the fluid and giving a false reading??

I'm just taking shots in the dark and trying to be supportive.

 

[AWSubie]

You mentioned you have a hydraulic top link on your box blade. Disconnect the hydraulic top link from your remote. The idea being to reduce the amount of hydraulic flow in the system so that the suction side has the least amount of volume to supply during the initial self purging of the air that was introduced during the oil change.

The only other thing I can think of is that because it is so cold the gasket on your hydraulic filter may have taken a set in the cold, and isn’t quite sealing allowing air into the system but again, if you installed the hydraulic filter when it was warm that wouldn’t be the issue

 

[crashz]

This is a tough one. I have a couple of thoughts, but it ends up being a combination of most of the advice given so far:
- Warm everything up. This fluid may be just too thick. But I think you would be able to see a difference. One would act like a light oil and the thick one like honey if cold viscosity is truly a problem.
- Find the suction side of the pump and make sure the piping looks good to that point.
- Overfill slightly.
- Jack up the rear enough to get the fluid level as high as possible on the pump end.
- With the tractor off, I would remove a loader quick coupler and activate that circuit to see if you get any air bleeding. I would not do that while running, but the air bubble should push up the line if the fluid is flooding the suction side.

 

[DieselBound]

OK, and the winner is... JimR! Fluid was just too darn cold. I pulled out a propane heater (that I've never used) and blasted the filter and underside. Started up and zero complaints from the pump. Ran for a bit and shut it down and installed the new filter (no fluid added). Fired up and all was still good. Took a few laps around my driveway, hooked my forks back up and put it away. I have to say that this fluid, now that the pump can actually fetch it(!), feels VERY nice- everything feels so much smoother and quicker. I will see how things are when I go to use it (minimal use this time of the year- mostly relegated to moving around crates of firewood).

For what it's worth, this fluid is supposed to last a lot longer (won't be doing a fluid change for a while- likely send in a sample at 400 hrs; filter changes per schedule, of course).

Again, I cannot state how appreciative I am of everyone here. There are not a lot of forums with a LOT of great and knowledgeable folks.

 

[blenderbender]

I've done a fair number of fluid changes and this is the first time I've encountered this. Loader jerks a few inches and that's it. PTO spins, but it doesn't seem very vigorous. Steering isn't happening (no power).

I'd over-filled a bit so I removed fluid to just under full.

Haven't run for more than a couple of minutes (total) for fear of damaging something. All Kioti filters. No issues changing anything. I am using semi-synthetic fluid, spec'd better than Kioti.

How best to work through this?

I just had a similar situation with my Kubota B3000 tractor. But it was oddly different. I had just finished changing fluid & filters and started the tractor to move to it's parking spot. Loader and implement on rear functioned as expected as I moved the tractor. It was left sitting for a couple weeks before I went to use it again. After starting and a brief warm up I pulled to levers to raise the loader and rear implement off the ground. Nothing.... nada, no hydraulics whatsoever. Perplexed, as I had the tractor pretty well boxed in a tight spot, I finally tried just inching the tractor forward and backward a bit for no reason that made any sense to me. Much to my surprise that seemed to work and somehow the hydraulic functions returned. I have no idea, but for now everything seems to be working as it should.

 

[LoudonNH]

I’ve never had this problem, however I do remember reading in a manual that raising the loader and maybe rolling the bucket back and forth is a method of getting the hydraulic oil moving.

 

[masseyrider]

What 2 things have been replaced?
Hydraulic oil and the filter.
I almost went crazy with a similar problem on a Kubota I bought at auction.
New to me I went and changed fluids.
No hyraulics no matter what I, we, they tried.
Finally after an estimated $2500 repair was suggested by the dealer I took one last chance.
I replaced the new filter.
PRESTO!
It all worked for about$40 not $2500.
Seems something was wrong inside and it wasn't letting fluid through.
Hopefully that's all yours is.
Also possible is the oil you used is not compatible.
Changed a power steering unit on a pickup once.
Got a replacement at the wreckers from an almost new truck that had been in an accident.
Soon as they gave it to me I noticed it had clear fluid and the old had red.
They said it was compatible.
It was NOT.
Took me two days to finally purge it until I got full full power assist.

 

[porkinbean]

Check for external filter inside the hydraulic tank. Should be acessable either where the fluid line exits the tank!

 

[Gurney1010]

I'd read of folks pressurizing. I've got a radiator kit that I might be able to use (has a conical rubber piece for sealing to openings/holes). I would look to pressurize with the engine running, yes? (seems obvious to me but I don't want to make any assumptions)

Is it the gear pump that air locks? I ask because that's where I seem to feel cavitation (and hear it).

Try loosing the pressure line at the front pump. If you don’t know which one that is, trace it back from the loader valve. That will let the air flow from the pump. As soon as oil starts the deep out tighten the connection and your problem should be solved. I have to do this with my older JD 5210 whim it has set several weeks. There is a small seep leak in the suction line that causes it to lose its prime.