ZD21 Hole in Fuel Tank from Tire Rub

[Sebul]

I'm a nubie to the forum and would like to get some advice.

I've had a ZD21 diesel for years that recently developed a leak in the fuel tank. The leak in the tank was caused from the left tire rubbing the side of the plastic fuel tank. Has anyone had any experience with this happening before?
The tire was not overinflated. I don't see any evidence of the tire being damaged or out of alignment.
The only thing that I can think of is that the pressure in the tank caused it to swell over time. It is my
The fuel cap has two short tubes/openings on the bottom side of the cap. When I blow on them, neither one will allow air to pass.
I don't mind replacing the fuel tank and/or the fuel cap, but I do want to make sure that this will not happen again.
Any input on this would be appreciated.

Thank you

Follow up: At 200mps' recommendation, I added a photo.
Attached is a photo from the back of the ZD21, where the tire is rubbing to gas tank. (In the photo, you can see where I wedged a piece of plastic I cut out from a clear milk jug to direct the fuel into a drain pan, in lieu of it running down the tire. It was tight to get the plastic between the tire and gas tank.)

 

[Palmettokat]

It is touching it sitting still now with fuel tank full? Hard to believe the tank material got soft enough to swell unless pressure on it. If sitting still the tire is clear of the tank these are my thoughts: could the bearings that left rear tire rides on be worn or damaged so it can move into the tank? I think that tank bolts to the frame but have the bolts loosen or been loosen so the tank is able to move towards the tire? is it build up of mud on the tire rubbing the tank? Could you be making hard enough turns the tire is being pushed into the tank? I would suspect worn bearings or mud build up doing the damage.

 

[200mph]

Just a thought...
Several pictures of the situation might help others understand and provide more accurate responses.

 

[Sebul]

It is touching it sitting still now with fuel tank full? Hard to believe the tank material got soft enough to swell unless pressure on it. If sitting still the tire is clear of the tank these are my thoughts: could the bearings that left rear tire rides on be worn or damaged so it can move into the tank? I think that tank bolts to the frame but have the bolts loosen or been loosen so the tank is able to move towards the tire? is it build up of mud on the tire rubbing the tank? Could you be making hard enough turns the tire is being pushed into the tank? I would suspect worn bearings or mud build up doing the damage.

Thank you Palmettokat.
I haven't tried it with the tank full, but I feel sure that the tire would still be touching. I am with you about the rigidity of the tank. It may be a plastic tank, but it is very rigid.
There is no mud on the inside of the tire.
I doubt if hard turns would be an issue. (If i turn too hard, it tears up the grass.)
The tank bolts don't appear to be loose, but I have not checked.
I did not think about the wheel bearings. I will jack it up this evening to see if there is any play in that wheel. I am not sure what is involved in replacing the wheel bearing, but that seems like a logical candidate.

 

[Sebul]

Just a thought...
Several pictures of the situation might help others understand and provide more accurate responses.

Thanks for the suggestion. I edited the original post to add a photo. I may have some additional photos later this evening, after i jack it up and pull off the tire.

 

[Sebul]

UPDATE - PROBLEM SOLVED

It finally came to my attention that the tire was installed the wrong way on the shaft. The rim should have been flipped. The offset in the rim pushed the tire too close to the fuel tank, causing it to rub.

I noticed, when I check the air in the tires that the left stem was on the inside and that the right valve stem was on the outside. That should have thrown a flag them, but I didn’t think much about it.I’ve had the tractor for two, possibly three years and I never noticed it. Thankfully, I don’t put too many hours on it. Unfortunately, it was enough hours to wear a hole in the tank

Now I’m going to see if I can save some money and repair the tank, iieu of buying a new one.

Thanks for everyone’s input

 

[200mph]

Glad you found the root cause and at least that portion is easy to fix.

 

[Palmettokat]

The thought the tire could be on backwards did come to my mind and I said, nah. Also verify the simple first. lol

You might want to ask mower shop what to use to repair that tank.

 

[PoTreeBoy]

Good tor you! You might be able to weld it up, depending on how much fuel has soaked into that plastic. Otherwise you might sandwich it between something like 2 fender washers and use diesel resistant RTV. Good luck.

 

[Sebul]

Another Update:

I used a fiberglass repair kit to patch the hole in the tank. (I spoke to someone else who used the fiberglass kit to repair a tank. It has held for several years for them.) So far, the repair seems to be holding. Only time will tell.

Thanks to everyone who helped me out on this.