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Valve stem rubber to brass air leak.

Posted: Mon Oct 06, 2025 2:57 am
by Novice
I have a model T with three tires with the same problem a leak in the valve stem where the rubber joins the brass threaded top section with the Schrader valve. The tubes are about five years old rubber on valve stems looks good on all of them. not cracked. last one started leaking after I aired it up to pressure. Had gone down over the last few months sitting.

Are there any fixes short of replacing the tube which may be the only answer. Seems like the right epoxy mix or other
sealer. using a o-ring and sealer to stop rubber to metal leak ? might work. Have not tried any repair yet. wanted to check with the old heads who have been there and done that to see what is recommended .

Thanks
Novice

Re: Valve stem rubber to brass air leak.

Posted: Mon Oct 06, 2025 6:41 am
by Humblej
Yes there is a simple repair. Lots of older posts about cutting off a valve stem and installing an original clamp on stem on an inner tube.

Re: Valve stem rubber to brass air leak.

Posted: Mon Oct 06, 2025 7:16 am
by Dan Hatch
Have seen that a lot on tubes in past. Think there was a batch of bad ones.
To get by you can put a small hose clamp on the stem just below the metal. Sometimes that will work as a temporary fix.

Re: Valve stem rubber to brass air leak.

Posted: Mon Oct 06, 2025 7:35 am
by Luxford
This is a common problem the tube valve stems are rubbish, the stems are not capable of dealing with the 60psi pressure .
Here is a photo of one cut open to show what the problem is.
Note there is no contact with the rubber except at the very end where the rubber is vulcanised to the metal stem by only about a millimeter of rubber. The white stuff is powder, it can go right up to the end of the metal stem.
On the road use a piece of wire, wrap it around the stem and twist it which will squeese the rubber tightly stopping the leak. Or use a small screw clamp for rubber hose to clamp the rubber.
When at home, get the correct metal valve stems and install them.
I had this problem when driving to Richmond for the 2008 centenial, I has soft wire in the tool box which I used until I went to an auto store and purchased the screw clamps. I still have one tire with the hose clamp on the valve stem now. So 14 years and the valve stem is still not leaking.

Re: Valve stem rubber to brass air leak.

Posted: Mon Oct 06, 2025 9:20 am
by TXGOAT2
I've had that happen on old stems and some not so old. I used the soft wire method with good results.