NX6010 suction side hydro leak

[justman777]

Hey, no worries! I may be chasing ghosts, but my previous John Deere with HST didn't make a sound that I could tell. No gurgles, burps, chugs....nothing. If this is normal for this tractor, I'll have to re-establish my baseline and press on. But my gut tells me it isn't supposed to make the noise it's making.

I asked my dealer about the "wind tunnel" noise, and he emailed my video link to Kioti corporate HQ. One of the techs said the bubbles were "normal", and the noise sounded like one of the remotes was open, as the remotes dumped fluid at the top of the sump. He recommended I confirm they were centered. I did. They were dead on. I even disconnected them and manually moved them back and forth and managed to deadhead the hydraulics and bog the engine down briefly. No change in the noise. Since I still heard fluid spraying, I asked if the remotes had a constant supply that bypassed if they weren't active and went back into the sump. Waiting on a response for that one until Monday

My next step is to borrow a borescope from one of my friends at church and see if I can tell where the wind noise (fluid spray) is coming from, if for nothing other than my own knowledge.

After that, I think I'm going to try putting in a clear PVC line where OverTaxed had his put...between the filter assembly and the pump on the suction side and see if I can see bubbles. If I do, I think I'm going to have the dealer replace the entire suction side assembly.

 

[JimR]

Hey, no worries! I may be chasing ghosts, but my previous John Deere with HST didn't make a sound that I could tell. No gurgles, burps, chugs....nothing. If this is normal for this tractor, I'll have to re-establish my baseline and press on. But my gut tells me it isn't supposed to make the noise it's making.

I asked my dealer about the "wind tunnel" noise, and he emailed my video link to Kioti corporate HQ. One of the techs said the bubbles were "normal", and the noise sounded like one of the remotes was open, as the remotes dumped fluid at the top of the sump. He recommended I confirm they were centered. I did. They were dead on. I even disconnected them and manually moved them back and forth and managed to deadhead the hydraulics and bog the engine down briefly. No change in the noise. Since I still heard fluid spraying, I asked if the remotes had a constant supply that bypassed if they weren't active and went back into the sump. Waiting on a response for that one until Monday

My next step is to borrow a borescope from one of my friends at church and see if I can tell where the wind noise (fluid spray) is coming from, if for nothing other than my own knowledge.

After that, I think I'm going to try putting in a clear PVC line where OverTaxed had his put...between the filter assembly and the pump on the suction side and see if I can see bubbles. If I do, I think I'm going to have the dealer replace the entire suction side assembly.

I replaced that suction line on my NX4510HST because it got torn. I put in a clear line also. There are no bubbles in the suction fluid flow. I also do not get any gurgles in my hydraulics. Something is fishy here.

 

[justman777]

Well, the borescope didn't work out. Camera wasn't small enough for me to get it turned without dipping it into the hydro fluid. Probably wouldn't have hurt it, but it was borrowed, and I wasn't going to risk it.

Jim --- what type of clear line did you use? The reinforced PVC I can get at Lowes/HD are all temp rated for something like 140 degrees. Thought the trans temp would be a little too hot for it.

 

[JimR]

Well, the borescope didn't work out. Camera wasn't small enough for me to get it turned without dipping it into the hydro fluid. Probably wouldn't have hurt it, but it was borrowed, and I wasn't going to risk it.

Jim --- what type of clear line did you use? The reinforced PVC I can get at Lowes/HD are all temp rated for something like 140 degrees. Thought the trans temp would be a little too hot for it.

I got mine at Lowes because HD did not carry the one I wanted. The size was just a little on the small size. I heated it up slightly with a heat gun to get it on easily.

 

[justman777]

Jim---was it 1.25 inch reinforced vinyl tubing?

 

[JimR]

I think it was 1 inch.

 

[justman777]

I think it was 1 inch.

Okay. They're cheap enough that I think I'll get a foot of each....just in case I need one or the other for something else in the future. Thanks!

 

[MinnesotaEric]

Treefarmer, I had the dealer send me the part as a warranty claim. However, it didn't fix the issue. I'm still getting the noise and bubbles in the sump.

This has me stumped. I'm thinking cavitation, but I'm not a hydraulic engineer. I'm just a somewhat mechanically inclined person of average intelligence. So...I did the same thing I always do when something is broke and I don't know how to fix it. I go to YouTube! :laughing:

I found the video here that may help us all out: All About Hydraulic Cavitation - Wrenchin' Up - YouTube

I discerned a few things from the video. First----the hydraulic system should NOT have ANY air in it. Like at all. Any air is very, very bad for your hydraulic system. Second----there's a few more possibilities to consider other than cavitation. The guy giving the demo shows cavitation, pseudo-cavitation, and turbulence.

Watching this video got me to thinking....is it cavitation, or is it pseudo-caviatation? Or, is the return line sitting above the oil level and it's causing turbulence, which in turn is causing air to be put into the fluid? From the video, it looks more like pseudo-cavitation than actual cavitation, because in true cavitation, the bubbles would collapse in the pump and you wouldn't have any air being put back into the sump. Psuedo-cavitation (what we're calling an air leak), however, causes air bubbles to go all the way through the hydraulic system and wind up in the sump. Turbulence caused by the return line being above the level of the sump fluid could also be the cause of air getting into the system.

I obviously can't test for pseudo-cavitation, but I wonder if over-filling the sump would bring the oil level up enough to test for turbulence.

Thoughts, anyone?

Yes, if air is getting introduced by the return line dumping into the tank/transmission, then filling up the hydro system should reduce the amount of air.

Maybe. Somebody want to try to look into this. I'm too busy making a campground to putz on issues that are not broken as I only have summers to try to get work done.

 

[justman777]

Got the clear hose today. Weather has cooled down a bit, so think I may tackle putting it on tomorrow. Unfortunately, it means dumping the trans fluid, unless I can figure out the shop vac trick. Probably just empty it out from the regular drain just so I can control it without making a mess.

 

[JimR]

Got the clear hose today. Weather has cooled down a bit, so think I may tackle putting it on tomorrow. Unfortunately, it means dumping the trans fluid, unless I can figure out the shop vac trick. Probably just empty it out from the regular drain just so I can control it without making a mess.

I put a large drain pan under the filter and hose area. I cut the hose and let it drain out. I don't recall having more than a few gallons drain out. I then took the intake pipe off from the pump on the motor. Installed the new hose but left the hose clamps loose. I put the intake pipe back on and tightened the clamps, followed by filling the hydraulics up again.