Bad metal fittings in Kubota hydraulic pistons

[davemvy]

Hi all, I have a nearly new L 4701, my pride and joy.
I bought it with the Kubota backhoe with a hydraulic thumb.
In less than 2 years some of the fittings where the hydraulic lines thread into the pistons completely rusted to the point where the entire fitting was unrecognizable.
Interestingly fittings that were exactly the same adjacent looked almost brand new.
These are quite clearly "slag" metal fittings supplied either in error or by intent.
Kubota must be having this problem nationwide . They do not want to acknowledge they have an issue.
I hope that the company has the courage to get out front of this.

 

[BAP]

Could it be from all the salt air from living on an island in the ocean?

 

[lugbolt]

At this time, noone at Kubota knows of "the issue". I certainly haven't heard of it.

 

[Lil Foot]

I assume you mean "hydraulic cylinders".
How about some pics so we can better understand the issue?

 

[Kubota Newbie]

Bet it's Powder Coat! The film gets broken where the fitting threads in and corrosion starts. But the film strength is high enough that the corrosion continues rapidly without breaking through and it'll rust at an incredible rate because it stays contained under the PC film. So-so metal quality makes it even worse. Wouldn't wish powder coat on anybody. Haven't ever owned any powder coated steel item that didn't eventually rust terrible. B&S had some issues with certain body parts on Simplicity tractors in the early 2000's (Legacy driveshaft tunnels) prep wasn't washed off properly and the parts would almost dissolve under the powder coat finish. By the time it showed through it was too late, it was junk.

 

[GeoHorn]

Bet it's Powder Coat! The film gets broken where the fitting threads in and corrosion starts. But the film strength is high enough that the corrosion continues rapidly without breaking through and it'll rust at an incredible rate because it stays contained under the PC film. So-so metal quality makes it even worse. Wouldn't wish powder coat on anybody. Haven't ever owned any powder coated steel item that didn't eventually rust terrible. B&S had some issues with certain body parts on Simplicity tractors in the early 2000's (Legacy driveshaft tunnels) prep wasn't washed off properly and the parts would almost dissolve under the powder coat finish. By the time it showed through it was too late, it was junk.

Unlikely. If he's talkin about the fittings/flare-nuts on the ends of hoses where they attach to the cylinders... it's not uncommon that chemicals from using the equipt or from washing/pressure-washing the tractor has interfered with the anodizing of the nuts. Scrub them with a wire-brush and paint them with Ospho/phosphoric acid and they'll be fine.

<edit> I now see the OP posted pics and my response is N/A. Those pics are very telling of a mfr'r defect and Kubota should provide relief to the OP IMO.

 

[SRG]

Unlikely. If he's talkin about the fittings/flare-nuts on the ends of hoses where they attach to the cylinders... it's not uncommon that chemicals from using the equipt or from washing/pressure-washing the tractor has interfered with the anodizing of the nuts. Scrub them with a wire-brush and paint them with Ospho/phosphoric acid and they'll be fine.

It's rusted under the paint on the cylinder side of the connection.
He put pics in the OP.

 

[Brick Axelrod]

I have the same machine and backhoe . I do not have this issue as of yet. I will keep,everyone updated if I do.

 

[lugbolt]

The loader has a one year warranty. Tractor has two years. That said, why don't you call your dealer, and ask them to send a pre-approval in to Kubota to see if they'll buy you some new cylinders? Worst they'll say is "no". If it's out of warranty, they'll have to file for "good will assistance", which is a pain in the neck, BUT....it can be done. And lastly, if those two can't come through, call customer service if you haven't already.

Y'all keep in mind that the ONLY way Kubota knows that there "is an issue" is by warranty claims and secondly but to a lesser degree, dealer case submission to the tech support center. In other words, if a bunch of dealers submit tech support questions all of the same nature, the TSC will notify the divisional office which will get the ball rolling toward an investigation. Similarly, if a whole bunch of warranty claims are submitted with the same problem, the warranty department will notify the divisional office who'll again start an investigation. I've been in on this stuff and they're REAL thorough with it, in a lot of cases have had the Japanese come over across the pond to get involved, of course with translators. That's what I did but at the shop instead of divisional office, but we found an interesting issue that plagued a couple of tractors...there weren't many, but there were enough to be of a concern in my opinion, same symptoms (unexplained trouble code) which we narrowed down to a VERY small machining defect. Kubota actually bought some of these tractors back and gave customer option to get into another one like it or take the money & buy a green or red tractor of their choice. They'll fix their issues if they can prove that it's their screwup, and that's why I suggested to contact the dealer first, then if needed go to customer service. Or go directly to customer service first if you think that might make you feel better.

 

[davemvy]

It is interesting to see all the theories.
I have never pressure washed this tractor. It is exposed part time to the air on the island bit as I said in my original post other fittings show no rust what so ever. I included a photo of both conditions. The rust is a complete breakdown of the fitting.
I have been a contractor for one year shy of 50 years. The only time I have seen anything like this is when lesser quality metal finds its way into a manufacturing process or system. It is not all fittings just some.
My dealer replaced all the hydraulic cylinders on the back hoe just in case.
They found one that they ordered had the same paint blistering around a brand new part and had to order another.
Kubota is not standing by the dealer but the dealer is standing by me.
I am very grateful to them. I did have to get the tractor to them, however. That was costly since I live on an island.

 

[GeoHorn]

...Kubota is not standing by the dealer but the dealer is standing by me.
I am very grateful to them. I did have to get the tractor to them, however. That was costly since I live on an island.

Don't know about Kubota...but when I worked for Toyota... if the dealership determined that a customer had a valid complaint which did not fit into the warranty-plan, the Toyota Distributor (Gulf States Toyota) who represented the factory would replace the parts in dealer-inventory at no-cost...and the dealer would only eat the labor.

 

[SidecarFlip]

Sure looks to me like a little bit of careful wire brushing and some Orange 2 Kubota paint would cure the issue.

Seems to me like a whole bunch of ado about nothing.

 

[Tire Biter]

Sure looks to me like a little bit of careful wire brushing and some Orange 2 Kubota paint would cure the issue.

Seems to me like a whole bunch of ado about nothing.

IDK. I’d be afraid to wire brush that, it looks ready to crumble.

 

[SidecarFlip]

IDK. I’d be afraid to wire brush that, it looks ready to crumble.

If it was (crumble), it would rupture and leak, it's a pressure fitting. Just surface rust from poor prep, nothing more.

 

[Yooper]

That is more than just surface rust in the first picture. Looks like a metallurgy issue that hopefully is isolated to just one fitting. Resembles the underside of what our vehicles look like from the salted winter roads here in Wisconsin.

 

[davemvy]

Hi,
I uploaded another picture. It is a close up and shows quite clearly the complete failure of the fitting. The previous comment suggesting a "metallugurical" issue is spot on. I never expected this kind of issue from Kubota. They need to face this openly. I cannot have the only machine where this is happening. For those of you suggesting a simple fix this new photo says otherwise.
The dealer has replace the units-my deep appreciation to them but before that I was very concerned that what was left of the metal would, in fact, blow out.
Thanks for all your thoughts and suggestions.
D

 

[RCW]

That is more than just surface rust in the first picture. Looks like a metallurgy issue that hopefully is isolated to just one fitting. Resembles the underside of what our vehicles look like from the salted winter roads here in Wisconsin.

Yooper - Coming from you, I think Dave has a point....my first thought was "so what," looks like upstate New York....

Does look like the fitting(s) are eroding badly, but not all of them....

Yooper - warranty or not, wouldn't you want to get those fittings out and replaced...while you still have something to get a hold of?

That fitting is not welded into the cylinder, is it?

Dave - FYI - Yooper is one of the best metal guys on OTT - if he or Lil Foot say it's "this way.." ...it is!!

 

[North Idaho Wolfman]

That fitting is not welded into the cylinder, is it?

Yes the part of the fitting that's bad is welded to the cylinder, so a cylinder replacement was the smartest answer.

Glad to hear the dealer stepped up and did the right thing by replacing them!

 

[Lil Foot]

Hi,
I uploaded another picture. It is a close up and shows quite clearly the complete failure of the fitting. The previous comment suggesting a "metallugurical" issue is spot on. I never expected this kind of issue from Kubota. They need to face this openly. I cannot have the only machine where this is happening. For those of you suggesting a simple fix this new photo says otherwise.
The dealer has replace the units-my deep appreciation to them but before that I was very concerned that what was left of the metal would, in fact, blow out.
Thanks for all your thoughts and suggestions.
D

Wow, that third pic is really telling.
What I suspect happened is that the maker of the cylinder (Kubota or a subcontractor) got a bad batch of the barstock used to make that weld-on bung.
(if it was a system wide material failure, everything on all cylinders, including the cylinders, would be in similar condition)
Having worked in aerospace my whole career, I'm quite familiar with disasters caused by suppliers substituting inferior materials. It usually happens when a supplier gets an order for (example) 100ft of certified XXX barstock, and they only have 85ft on hand- some knucklehead in the warehouse substitutes 15ft of non-certified YYY barstock to complete the order. Most manufacturers seldom test every piece of stock supplied, (kinda defeats the whole purpose of having certified, single source suppliers) so some crap makes it to the product.
Glad Kubota stepped up for you, quality failures like this are certainly not typical of Kubota. (Mahindra, maybe)

 

[Yooper]

Bill is right on! I'll guess that the welding pulled out something in that fitting(silicon, Bill?) that led to this happening. The dealer absolutely did the right thing and I'm glad it worked out for you, Dave. That right there is a loaded gun!