"Sticky" valve movement - can/should I flush with a U-hose?

   / "Sticky" valve movement - can/should I flush with a U-hose? #1  

JRobyn

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Dec 4, 2003
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Kubota L4330HST
Hi guys,

Two of my 3 newly-installed rear remote valves are both very "tight" (takes a lot of pressure on the levers) and seem to be "sticky" when they do move. Sticky enough that they don't return to center very well. Kinda have to be manually set there. The third (farthest outboard) is fine. Silky smooth. The valves are Kubota OEM with float, no manufacturer name is obvious on them. They sat in my climate-controlled basement for the better part of 2 years after I unwrapped them from the shipping wraps. They were SATURATED with a heavy oil inside and out from Kubota. I wiped off the outsides, but assumed that the insides were still plenty juicy. At least enough to prevent any rusting. All 3 have been assembled all this time together with the feed/return lines. Basement stays at 65deg +- about 5deg and 50% humidity +- about 10%.

Now, I fear that just from air migrating through the lines/valves, that the two inboard valve spools or bores have some rust that is causing what I'm feeling. After I got them plumbed, I flushed about a pint of hydraulic fluid through each "side". It was dark, but I didn't see any particulate matter. It also didn't really change their behavior.

So finally my question(s); have I likely ruined these 2 valves? Would it be advisable to connect a "U-hose" between the two rear connections for each of these valves and cycle them back and forth a few times in an effort to further flush and clean and polish the spools/bores? If I use a u-hose then any rust/debris will get routed back to the hydraulic sump, right? Tractor is an HST, so I'm worried about intentionally flushing ANYTHING, even to the sump. If I just connect my new cylinders and use them, any debris will be deposited inside the new cylinders and possibly contribute to early seal failure, right?
 
   / "Sticky" valve movement - can/should I flush with a U-hose? #2  

DLTTrekkers

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Paarl South Africa
newly installed....loosen 1 of the 2 mountingbolts and see what happens
 
   / "Sticky" valve movement - can/should I flush with a U-hose?
  • Thread Starter
#3  
OP
J

JRobyn

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Not sure I'm following - As in I may have distorted the valve bodies?

It's been quite a while since I assembled the 3 valves, but now that you bring it up, I don't recall for sure if I used a torque wrench on them. I'll slightly loosen and re-torque them all (there's 3), assuming you are talking the bolts that mount all 3 valves to the hydraulic block.
 
   / "Sticky" valve movement - can/should I flush with a U-hose? #4  

tvman

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Lebanon,In.
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Not sure I'm following - As in I may have distorted the valve bodies?

It's been quite a while since I assembled the 3 valves, but now that you bring it up, I don't recall for sure if I used a torque wrench on them. I'll slightly loosen and re-torque them all (there's 3), assuming you are talking the bolts that mount all 3 valves to the hydraulic block.

I'm just wondering if Kubota has changed something in their valves. The reason I say this is that their valves, in my opinion, are crappy.My 4330 is about 10 yrs old. I added the 3rd valve this past year.

None of the valves will hold the T&T cylinders in position for any length of time. I finally had to add check valves to fix the issue.

Maybe the two sticky valves are of a newer design in attempt to solve the leakdown issue.

There have been many comments in this forum about this issue .
 
   / "Sticky" valve movement - can/should I flush with a U-hose? #5  

oldnslo

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Jan 20, 2010
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Northern, IL
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Branson 2400H, JD X540
JR
Yes double check the torque on the tie rods holding the valve sections together. If this valve assembly is foot mounted to a plate possibly loosen those mounting bolts also. Sections clamped or twisted slightly would cause this binding issue.
 
   / "Sticky" valve movement - can/should I flush with a U-hose? #6  

Dave M7040

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Joined
Dec 10, 2012
Messages
2,705
Location
Williamstown Ontario Canada
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Kubota M7040 Nuffield 465
Hi guys,

Two of my 3 newly-installed rear remote valves are both very "tight" (takes a lot of pressure on the levers) and seem to be "sticky" when they do move. Sticky enough that they don't return to center very well. Kinda have to be manually set there. The third (farthest outboard) is fine. Silky smooth. The valves are Kubota OEM with float, no manufacturer name is obvious on them. They sat in my climate-controlled basement for the better part of 2 years after I unwrapped them from the shipping wraps. They were SATURATED with a heavy oil inside and out from Kubota. I wiped off the outsides, but assumed that the insides were still plenty juicy. At least enough to prevent any rusting. All 3 have been assembled all this time together with the feed/return lines. Basement stays at 65deg +- about 5deg and 50% humidity +- about 10%.

Now, I fear that just from air migrating through the lines/valves, that the two inboard valve spools or bores have some rust that is causing what I'm feeling. After I got them plumbed, I flushed about a pint of hydraulic fluid through each "side". It was dark, but I didn't see any particulate matter. It also didn't really change their behavior.

So finally my question(s); have I likely ruined these 2 valves? Would it be advisable to connect a "U-hose" between the two rear connections for each of these valves and cycle them back and forth a few times in an effort to further flush and clean and polish the spools/bores? If I use a u-hose then any rust/debris will get routed back to the hydraulic sump, right? Tractor is an HST, so I'm worried about intentionally flushing ANYTHING, even to the sump. If I just connect my new cylinders and use them, any debris will be deposited inside the new cylinders and possibly contribute to early seal failure, right?

Are the valves cable operated? If so, disconnect the cables at the valve and move the lever at the valve manually to see if they move easier.

Post a couple of pictures of both the valves and the levers

Dave M7040
 
   / "Sticky" valve movement - can/should I flush with a U-hose?
  • Thread Starter
#7  
OP
J

JRobyn

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Kubota L4330HST
No, all lever operated. Part of the problem is that the levers are not really the stoutest, most rigid things out there.

IMG_0215 (768x1024).jpg

IMG_0464 (768x1024).jpg

IMG_0467 (768x1024).jpg

IMG_0470 (768x1024).jpg

This one is before I reinstalled the levers.
IMG_0690 (768x1024).jpg
 
   / "Sticky" valve movement - can/should I flush with a U-hose? #8  

Dave M7040

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Williamstown Ontario Canada
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Kubota M7040 Nuffield 465
Thanks for the photos as it makes understanding your situation much easier.

I would be wanting to determine if your issue is hydraulic related, i.e. pressure in wrong place, no relief for pressure as compared to a mechanical deformation as some have suggested.

You state one of the three valves operates properly. Which one? I have marked up one of your photos with an A & B, so is the valve with no problem closest to A or to B or in the middle.
YFFCwqN.jpg


With the tractor off, move all three levers around to bleed off any pressure. As a final check, insert a quick connect into each outlet to be doubly certain. Be careful not to get a jet of high pressure oil in your face or skin.

Do the valves operate OK with no pressure? If yes then that is very useful info.

Before you started this project were A and B bolted together with no valve at all?

Operating a rear remote with it not connected to anything could create some issues as I try and imagine what is happening.

Knowing which valve operates properly will be a help in my imagination process.

If another one or two valves operates properly with no pressure but is sticky with pressure, then try it with a U hose to see if my concern about no where for the oil to go is part of the mix.

Were all three valves ordered at the same time? Do they all have the same part number?

Did any instructions come with them which you could post?

Dave M7040
 
   / "Sticky" valve movement - can/should I flush with a U-hose?
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OP
J

JRobyn

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See embeds below...

Thanks for the photos as it makes understanding your situation much easier.

I would be wanting to determine if your issue is hydraulic related, i.e. pressure in wrong place, no relief for pressure as compared to a mechanical deformation as some have suggested.

You state one of the three valves operates properly. Which one? I have marked up one of your photos with an A & B, so is the valve with no problem closest to A or to B or in the middle.
YFFCwqN.jpg


"B" is smooth.


With the tractor off, move all three levers around to bleed off any pressure. As a final check, insert a quick connect into each outlet to be doubly certain. Be careful not to get a jet of high pressure oil in your face or skin.

Do the valves operate OK with no pressure? If yes then that is very useful info.

"A" and middle are still sticky with tractor off. They are slightly less so when running.

Before you started this project were A and B bolted together with no valve at all?

No, the whole kit, hydraulic takeoff block, lines, valves, end block, mounts, went on at once.

Operating a rear remote with it not connected to anything could create some issues as I try and imagine what is happening.

I did this very briefly, and as expected, the hydraulic relief immediately complained.

Knowing which valve operates properly will be a help in my imagination process.

If another one or two valves operates properly with no pressure but is sticky with pressure, then try it with a U hose to see if my concern about no where for the oil to go is part of the mix.

Were all three valves ordered at the same time? Do they all have the same part number?

Yes, all at the same time. I'm not sure about p/ns, and I won't be taking it all back out to check!

Did any instructions come with them which you could post?

Only the typical Kubota 1-2 pages of drawings and icons.

Dave M7040
 
   / "Sticky" valve movement - can/should I flush with a U-hose?
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J

JRobyn

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Ding! Ding! DLTTrekers is a genius! I finally got a chance to get back out there this afternoon (having a few health issues) and loosened all 3 of the "gang bolts" to just a bit tighter than finger tight. All 3 valves are glassy smooth! I am astounded that heavy cast iron can distort that easily. I can't get the torque wrench in where they are (in my present condition), but my guess was that they were all too tight. Kubota specifies 22.5-24.5 Nm. Maybe I assumed that since I was going with 3 valves stacked and much longer gang bolts that a little extra would be good? I dunno.

I will leave the assembly at least overnight to "relax" and see if I can get my wife to get down on the ground with the torque wrench to bring them back to EXACTLY 22.5 Nm!

Thanks to everybody and especially DLT!
 
 
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