ZD326 Frozen Scalp Wheel Shaft Troubles

[Mr Haney]

I can't find much reference to my problems with my ZD326 mower's anti-scalp wheels, so I guess I should tell all now.

When I bought this mower, I noticed there were no front anti-scalp wheels on the corners of the deck. The seller offered me a big discount for this and other reasons, and he said his dealer had told him he didn't need these wheels on Florida's flat ground. I knew what the parts for new wheels cost, and I figured it wasn't a big issue.

I did NOT notice that there was no paint on the tubes for the front wheel shafts. Somebody had used a torch to get the old wheel shafts out. It was either the seller or the old guy who died and left his wife the mower. I should have realized this meant there would be similar problems with the rear wheels.

I eventually realized I needed to change the height of the rear wheels. They were a little stiff, however. As in frozen in place. The shafts were stuck to the upright tubes.

For a couple of weeks, I have been trying to fix this. A three-foot pipe wrench didn't work. Air hammer. Machinist's sledge. Penetrating oil. None of that worked.

I eventually decided to drill the port shaft out of its tube with a cordless drill. I figured I might make it so thin, it would be easy to collapse it and get it out.

I blew up the drill using Silver & Deming bits to get the shaft out. I ended up turning the shaft into a pipe with about a 1" hole all the way through. I cut off the ends so there would be less metal to deal with.

Yesterday I started trying to split the pipe lengthwise. I used a carbide burr and a hacksaw, inserting the hacksaw blade in the pipe and reattaching it to the handle.

Today I decided to try heat before continuing. I heated the shaft to over 300 degrees, and I froze it afterward. I did this several times, and nothing moved.

I bought some sawzall blades and went to town. From time to time, I peeled the shaft shell away from the tube and used a hammer and punch to try to pry it off the tube.

Eventually, the shaft shell fell out while I was hammering the punch. I couldn't believe it.

If you look at the photo, you may be able to see that the rust that welded the shaft to the deck is extremely thin. A film. It could develop in a season. It was unbelievably dumb for Kubota to make the fit so tight. There was no reason for it. The penetrating oil was all over it, but it didn't help one bit.

I cut into the deck tube a little, but it's nothing JB weld or something won't fix. Once I paint it, it will be fine.

The starboard tube was even worse. One of the horizontal adjustment pins was stuck in it. The natural things were to oil it, try to turn it with vise grips, and tap the inboard (small) end with a hammer. I got it to turn freely, but the hammer (mine or a previous owner's) mushroomed the small end of the pin. I decided to cut off the head and see if I could push it out backward, and it worked. After I ordered a slide hammer. Which I should keep anyway, because I don't have one.

I am now in the process of cutting the starboard bracket or ear or whatever off the deck. It is easier to weld it back on than it is to work on it while it's attached. I'm going to put it in my hydraulic press, and if that doesn't work, which I really doubt, I will find a way with the mill or lathe. If all else fails, I can buy a piece of steel, make my own tube, throw out the old one and the shaft, and weld the new one on.

Tomorrow, I should have the starboard shaft out OR I should confirm that it's useless to try, so I can get started on making a new one.

I really like Kubota, but every manufacturer has at least a couple of stupid engineers, and it looks like Kubota assigned theirs to anti-scalp wheels.

My yard hasn't been mowed in two weeks. I can't bear to use the John Deere again after using the Kubota. The new parts arrive Tuesday, so by Wednesday night, the yard should be back on its way to recovery.

 

[D2Cat]

Maybe drill and tap a hole for a grease fitting?

 

[Hugo Habicht]

... It was unbelievably dumb for Kubota to make the fit so tight. ...

Reading this and all your other posts I think you are way smarter than all the Kubota engineers. For example replacing a safety electronics box by simply a few wires. This is ingenious !

I think you should design and build your own lawn mower.

Really.

Have a nice day.

 

[GeoHorn]

Without actually “being there”… it’s too easy to imagine my own methods would have been easier….but, of course that’s just over-simplification and unworthy of belief. (you shohld be congratulated for perseverance! That reads like a really frustrating experience.)
I imagined that first, …a torch should have been used to heat the tube/collar, …causing it to expand and free the shaft, which might then be driven out.

Who knows what the previous owner did to neglect that system so as to result in such a frozen/rusted mess…. but clearly, he didn’t keep it lubed or stored properly. (The front wheels having been cut-off completely are a clue as to the care not given the mower.

I don’t blame Kubota for poor-design…(too many other mfr’s use the same method without difficulties)…. I blame the previous owner for failure to properly maintain it.

A good waterproof grease should be used on bare, exposed shafts like that. A zerk might be useful, but even without zerks, the shafts could be pulled and wiped-down with grease.

While your’e at repairing it, you might wish to consider re-installing the front ant-scalp wheels. A junk yard out in the back of some mower-repair shops might be a good source for completely replacing those.)

 

[Mr Haney]

Reading this and all your other posts I think you are way smarter than all the Kubota engineers. For example replacing a safety electronics box by simply a few wires. This is ingenious !

I think you should design and build your own lawn mower.

Really.

Have a nice day.

Thank you for the recognition, but it's not that I'm clever. I just look smart when I expose and fix absurdly incompetent engineering.

It's actually very common for untrained people to improve products designed stupidly by experienced engineers.

 

[Hugo Habicht]

Thank you for the recognition, but it's not that I'm clever. I just look smart when I expose and fix absurdly incompetent engineering.

It's actually very common for untrained people to improve products designed stupidly by experienced engineers.

Has been mentioned already: what you encountered is absurdly incompetent operators.

I would suggest to consult the operator manual, section "maintenance".

 

[Mr Haney]

Without actually “being there”… it’s too easy to imagine my own methods would have been easier….but, of course that’s just over-simplification and unworthy of belief. (you shohld be congratulated for perseverance! That reads like a really frustrating experience.)
I imagined that first, …a torch should have been used to heat the tube/collar, …causing it to expand and free the shaft, which might then be driven out.

Who knows what the previous owner did to neglect that system so as to result in such a frozen/rusted mess…. but clearly, he didn’t keep it lubed or stored properly. (The front wheels having been cut-off completely are a clue as to the care not given the mower.

I don’t blame Kubota for poor-design…(too many other mfr’s use the same method without difficulties)…. I blame the previous owner for failure to properly maintain it.

A good waterproof grease should be used on bare, exposed shafts like that. A zerk might be useful, but even without zerks, the shafts could be pulled and wiped-down with grease.

While your’e at repairing it, you might wish to consider re-installing the front ant-scalp wheels. A junk yard out in the back of some mower-repair shops might be a good source for completely replacing those.)

The torch had no effect, unfortunately. Like the sledge, the oil, the pipe wrench...

The problem with zerks is that there is no journal. Also, these shafts don't turn, so the grease would not be distributed. I think anti-seize applied manually at least twice a year will work.

If Kubota had made these shafts a few thousandths smaller, like John Deere, they could never freeze up except possibly in extreme conditions. These Kubota shafts can lock up very quickly, even if kept indoors.

The humidity is high here, and we get big temperature swings, so water condenses on metal at night and causes rust during the day. This happens indoors as well as outdoors. This mower doesn't appear to have rain damage anywhere. It appears condensation ran down the sides of the shafts over and over on winter days, entering the tubes and causing rust.

I am tempted to put the new shafts on the lathe and knock 50 thousandths off the diameter. The plating is worthless, so removing it won't hurt anything. I could always plate them again with something better.

I ordered front wheel assemblies. There may be some shaft fragments stuck in the front tubes, so I might have to fix that.

The front tubes would have been fine if they had been greased. They have zerks and journals.

 

[Mr Haney]

Has been mentioned already: what you encountered is absurdly incompetent operators.

I would suggest to consult the operator manual, section "maintenance".

I have the manual, and there is nothing in it about greasing or cleaning the rear shafts. You should have read it before commenting. The previous owner had no warning from Kubota about this problem.

I don't see why you're angry. Forums exist to help consumers, not to exalt manufacturers and persecute people who expose them and provide fixes. Engineers make incredibly stupid mistakes all the time. Remember the Challenger?

 

[Hugo Habicht]

I have the manual, and there is nothing in it about greasing or cleaning the rear shafts. You should have read it before commenting. The previous owner had no warning from Kubota about this problem.

 

[Mr Haney]

Why are you proving my point?

 

[Russell King]

I have the manual, and there is nothing in it about greasing or cleaning the rear shafts. You should have read it before commenting. The previous owner had no warning from Kubota about this problem.

I don't see why you're angry. Forums exist to help consumers, not to exalt manufacturers and persecute people who expose them and provide fixes. Engineers make incredibly stupid mistakes all the time. Remember the Challenger?

The Challenger did NOT fail from an engineering error, it was launched outside the temperature range of the design parameters.

It seems you have trouble with engineers (as people) in general like many do for whatever reasons. Your statements about engineers are mostly derogatory or degrading.

Just because you disagree with the engineer’s decision does not mean that decision was wrong.

 

[Mr Haney]

Your statement about the Challenger sounds like something a defensive engineer would say. There was a huge investigation when the ship blew up, and if it had been well-known that the cold was an issue, it would have been a lot shorter. Instead, Richard Feynman had to point it out at a big meeting, after being nudged toward it by a general named Kutyna, who was apparently afraid to blow the whistle himself.

The O-rings that caused the problem were later changed, showing that they should have been better in the first place.

Saying I have a problem with engineers also sounds like something an emotional engineer or an engineer's dad might say. I think good engineers are fantastic. I wish I had gotten ME and EE degrees instead of physics. My uncle was a NASA liquid propulsion engineer, and I loved his familiarity with tools and materials.

I'm typing on a computer made possible by engineers, in a house with air conditioning made possible by engineers. My recliner's motor wouldn't exist without engineers. Engineers are wonderful. But some are bad at their jobs, and sometimes engineers do stupid things.

You haven't provided defenses for the engineers involved in the other disasters I mentioned, because there aren't any, and I could literally sit here and post more all day, every day, for a month.

I don't see why you are turning this into a personal, emotional issue. Everyone benefits from the exposure of bad products, except for the people who produce them.

 

[Russell King]

Then just state the problem you see and stop bashing the engineers. Yes I was an engineer so your comments are personally offensive to me and other engineers. But I don’t really get offended by your statements, they are somewhat amusing in their all encompassing breadth of engineers and repetitive nature.

You don’t seem to understand what a mistake is versus exceeding design limits or not maintaining the equipment properly. You brought up the Challenger disaster as a slam to the engineering profession making errors so I thought it acceptable to point out your error in that statement. You have made a second error in saying that making a change in the orings admits there was an error in the first place. That would fall under a design improvement or disaster mitigation plan to avoid further disasters in the future.

I see you are currently discussing the rear anti scalp wheels versus the front anti-scalp wheels. The non-mention of the rear in the service manual is not an engineering error, I am pretty sure a Japanese engineer would not write the manual, that is done by a technical writer usually. It was usually written in Japanese and translated into English so there is another problem you can probably state. But any user that read the manual and saw that there was front and rear wheels on the mower should have been able to make the mental leap to maintain them all in similar fashion. I further think the manual would state how to adjust the rear wheel height. As an engineer I would have assumed that most users of a mowers would adjust the height on a regular basis over each year and might maintain the shafts with something that would mitigate rust (just out of common sense), but I guess in your case they set it and forgot it leading to your predicament. I think if you open the clearance you may be likely to break the vertical shaft just below or at the static carrier on the mower deck. But you can certainly look at the physics of that joint and decide what is best for you as an individual.

 

[Mr Haney]

Then just state the problem you see and stop bashing the engineers. Yes I was an engineer so your comments are personally offensive to me and other engineers. But I don’t really get offended by your statements, they are somewhat amusing in their all encompassing breadth of engineers and repetitive nature.

You don’t seem to understand what a mistake is versus exceeding design limits or not maintaining the equipment properly. You brought up the Challenger disaster as a slam to the engineering profession making errors so I thought it acceptable to point out your error in that statement. You have made a second error in saying that making a change in the orings admits there was an error in the first place. That would fall under a design improvement or disaster mitigation plan to avoid further disasters in the future.

I see you are currently discussing the rear anti scalp wheels versus the front anti-scalp wheels. The non-mention of the rear in the service manual is not an engineering error, I am pretty sure a Japanese engineer would not write the manual, that is done by a technical writer usually. It was usually written in Japanese and translated into English so there is another problem you can probably state. But any user that read the manual and saw that there was front and rear wheels on the mower should have been able to make the mental leap to maintain them all in similar fashion.

I have to pat myself on the back for guessing your profession.

You repeatedly insist I bashed engineers as a whole ("all encompassing breadth") even though I successfully proved that I didn't. I never bashed all engineers. You shouldn't say I did. I bashed bad engineers and bad engineering.

You're not really amused by my statements. People often say they're amused when they're offended. It's a way of condescending. Sometimes they say, "I feel sorry for you," or, "I'll pray for you," but it's the same thing.

The folks who designed the Challenger seals should have foreseen 36-degree weather in Cape Canaveral. They should have known Cape Canaveral's record low was 17 F. It's pretty obvious. Failing to plan for it was a mistake.

The front and rear wheels on my mower are very different, as you will see if you look at a parts manual. The front wheels swivel continuously and have zerks and journals for greasing to prevent wear (not galling, which should not happen in a moving part). The rear wheels never move except when the deck has to be removed from the mower or the height has to be changed. The bores have no zerks or journals, and grease isn't intended to prevent galling anyway. The correct substance is anti-seize, and in the case of the rear wheels, it would have to be applied manually due to the lack of movement, zerks, and journals.

For many pros, changing the height of the wheels might be a frequent procedure, but not so for homeowners or people who mow on flat ground, which includes a lot of America. Not so for pros during the down season. The rust film that locked my wheels was a couple of thousandths thick, at best, so it is obvious it could have occurred in one yearly layoff.

Removing the deck is rarely necessary for this mower because it has a maintenance jack built in, and the gearbox and the top of the deck are accessible through a hatch. That means it's not realistic to rely on deck removals to keep the wheels loose.

Compare all this aggravation to simply making the shafts slightly thinner, as other manufacturers have. It causes no problems, and it prevents galling. My old JD is 34 years old, has loose shafts, and doesn't have any shaft or deck damage because of it. Its shafts require no greasing. There are no zerks. Kubota could have done the same thing, and given that its competition was doing it in 1984 and possibly earlier, failing to do so in a very expensive 21st-century mower is inexcusable.

You tell me, as an engineer. Is relying on unusual counterintuitive maintenance procedures done by the customer, with no mention in the manual, the best way to go, or do you simply design the product not to create a problem in the first place? Do colleges teach engineers to take the first option? No. Of course not.

The guy who bought this mower new definitely should have done better, but the engineers also set him up.

All this fuss reminds me of people who get mad when I criticize the failure-prone AR-15 and recommend reliable AK variants instead. A huge percentage of AR talk on the web is devoted to simply making the guns run nomally, which tells you they're unreliable. AK forums aren't bogged down in discussion of fixing FTF's and FTE's because AK's have much lower failure rates, but heaven help you if you point out the obvious to a guy who just dropped $4,000 on an AR made from titanium and platinum.

Knock a few thousandths off a ZD326 anti-scalp shaft, and it will never, ever seize, and it will not cause new problems. Kubota could have done this. That's the bottom line.

 

[JasonW]

That's the bottom line.

Bottom line is you bought an abused machine because of the price and it seems like you’re constantly complaining about fixing things on it.

I stoped responding in your other threads after you were concerned about the control levers being sun faded. And complaining when you ran it out of fuel stating the fuel gauge was hard to understand. Then the starting issues about the controller and safety switches.

 

[Mr Haney]

I bought a mower I didn't know had been abused because I was an inexperienced buyer, and it looks like the seller wasn't all that forthcoming. When I sell people stuff, I tell them everything that's wrong with it.

I took full credit for misunderstanding the fuel gauge. Kubota provided a sticker than explained it, but the stickers from the control panel were gone by the time I arrived, and I didn't know there had ever been one by the fuel gauge. I replaced it a while back.

I wanted to replace the lever grips because the mower was starting to look like it would work out really well, so I felt like spending some money on its appearance.

The mower did have starting issues, so I analyzed the system, wrote a detailed report, and posted it here to help other people. Thanks to me, other people can run their mowers after the ECM's die. I don't see the problem with that.

 

[Hugo Habicht]

I see you are currently discussing the rear anti scalp wheels versus the front anti-scalp wheels. The non-mention of the rear in the service manual is not an engineering error,

The wheels in question are referred to as "front anti scalp roller" in the manual. The rear wheels are the wide cylindrical ones that are maintenance free.