Flat tire, tube not leaking

[geneP]

My tractor rear tire was flat in the shed. I aired it up and drove it to the shop to repair it. I aired up the tire and checked the stem for a leak and found none. I removed the tube from the tire and aired it up expecting to find a hole in the tube, but none was evident. So I aired it some more and sprayed soap solution on it. Still nothing showing. It has been sitting a day and hasn't lost any air. What could be happening for a tire to go down with the tube in the tire and the tube not show a leak? I don't think it is a one-time fluke because a few weeks ago it was flat when I wanted to use it , so I aired it up to get the job done that day. I don't want to put it back together and have it go flat again. I'm 75 and breaking down a tractor tire isn't fun any more. I would buy a new tube if I knew that was the cause, but this one isn't loosing air. This isn't rocket science, what am I missing?

 

[Creamer]

Interesting problem. Obviously air has to be coming out somewhere for the tire to go flat. If you have the tube out of the tire it is not constrained and therefore stretches more than it would in the tire. so if it had a hole in it it would open more than it would in the tire and would leak. Holes in tubes do not seal themselves.

My bet is the valve is not functioning consistently. This could be a function of the valve or leaking around the fit of the valve into the stem. I would remove the valve and get a light and magnification and check the seat in the valve stem for any damage - if it is then it is obviously a new tube. If it doe snot appear damaged I would install a new valve and pump up the tube and let it set for a day and come back and see if it has leaked at all. If not I would put it back in the tire.

 

[CobyRupert]

Magic? Immaculate deflation? Did you anger a voodoo priest neighbor who sticks a pin in a toy tractor tire, then pulls it out when you pull the tube? Did you inflate tire with hydrogen molecules that can escape instead of air?

Probably not, I'd bet you have to be missing something. Maybe where the valve stem attaches to tube? Maybe if not being contacted by the rim it doesn't leak.
Like you said, breaking it down is a pain, splurge on a new tube and call it done. :2cents:

 

[teg]

Neighborhood kids letting the air out? I would replace it since you have it open and keep the tube as a spare...

 

[TractorGuy]

I would bend the stem around and check it.

The kid suggestion might be on to something?

Had a tubless leak drive me crazy one time. It was on a aluminum Miata wheel. Darn thing would go flat one day and you pump it up and then it might not go flat for a month. Couldn't find a leak pressure would stay constant then one day it would be flat again. I clean the wheels up and repainted them one day and it never leaked again.

 

[Creamer]

I would bend the stem around and check it.

The kid suggestion might be on to something?

Had a tubless leak drive me crazy one time. It was on a aluminum Miata wheel. Darn thing would go flat one day and you pump it up and then it might not go flat for a month. Couldn't find a leak pressure would stay constant then one day it would be flat again. I clean the wheels up and repainted them one day and it never leaked again.

I know that feeling. On my '99 Deville I lost four tires due to them going flat while I was driving and ruining them. It always happened on the coldest days and always rim leaks. i started asking around and one guy at a tire shop said it was a chemical interaction between the Michelin tires and the aluminum wheel. It always happened on cold days because the rubber was stiffer. He said to switch to Mastercraft tires and the problem would go away (MasterCraft was the only other tires made in a whitewall in that size). I did and have not had a flat in the last 100k miles so I think he was right.

 

[flyerdan]

If there are no leaks in the tube body it has to be leaking from the valve core. Swap it out, and if it still fails the bubble test, use a metal cap with a gasket in it. I have one on a filled tire on the Bobcat with a bad core, it keeps the fluid and pressure in.

 

[geneP]

Well, the tube stayed up over a day. I took the advice of Creamer and inspected and cleaned the seats of the valve stem lubed the seats and put it back together. I didn't want to drive 1.5 hours to get a tube. Still no leak at the stem after re-assembly. Hopefully it will be OK
Thanks for the advice.

 

[Creamer]

Uh-Oh. You took my advice - I'm keeping my fingers crossed now!'


Good luck!

 

[Gary Fowler]

And keep an eye out for those demon kids (or larger person) that might be doing their mischief.