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inner tube valve stems


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I have the correct Schraeder valve stems for my spoke wheels but have been unsuccesful in having them installed leak tight. Out of 10 attempts by Coker, 7 have leaked. This has been a major problem because my powder coated wheels have suffered greatly during the removal and installation of the lock rings multiple times.

Recent discussions with Coker reveal that they will no longer install valve stems provided by customers. They don't sell an authentic alternative (90 degree bend at 1 1/2 inches, threaded).

I talked to Universal and they do not want to attempt it.

Does anyone know of anywhere I can have the stem installed into a new tube? These metal stems were installed in tubes for years. Why is it so impossible to do now? For information, Coker was just cutting off the stems on their tubes and then inserting the base of my stems into the hole with the bridge washer and nut installed after that. Nothing was used to seal around the stem in the tube. How did they do it originally?

Any help will be appreciated.

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  • 2 weeks later...

Alan,

The tubes for my car also call for the nickle plated stems. I am curious on where this stands with any manufacturer?

If the nickle stems just don't work I will resort in just purchasing the tires with the rubber stems. Authentic or not it would probably be our best bet.

I have been watching this thread also http://forums.aaca.org/f169/inner-tubes-beat-goes-323894.html

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I installed repro metal stems in an innertube by cutting off the rubber stem and carefully sanding the area smooth to remove any high spots. Then I coated the base of the valve stem with rubber cement and inserted it in the hole so that it would seal up from the inside. Then I added more rubber cement around the valve stem on the exterior of the tube before intalling the bridge washer and nut to seal it from the outside. I torqued that nut pretty tight. So far, no leaks.

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I have metal stems from coker. They were not glued on. 2 were fine and the others I had to tighten the fasteners and then they did not leak. I would maybe use some silicone rubber as a sealant if I did them myself instead of rubber cement but both ways would most likely work. There is no real trick to stopping a leak it is just the fact that it needs plugging or tightening.

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Thanks to everyone who provided their comments. Here's what I have learned and where I stand on this at the present time based upon discussions with others in the hobby and in the business:

First of all, 90 degree bent stems are available from the manufacturers, although I don't know if they are nickle plated and I don't know if they are threaded so they can be properly attached to the rims. I want mine to look exactly as original, plus those available bend at 2" and I need mine to bend at 1 1/2" to avoid contact with the spokes on my wheels. I know the 1 1/2" variety are not available.

Back when these stems were commonly used, they were apparently vulcanized to a patch, and then that patch was vulcanized to the tube. They weren't just stuck through a hole in the tube as Coker was doing. When my first six leaked I asked them why they didn't use any type of adhesive or sealant and they said it was not necessary.

One friend who had the same problem as I was having cut the tube open and found that the surface surrounding the hole where the stem had been cut off was not flat and even. His fix was to patch the original hole, then install another patch a few inches away where he could expect a smooth, flat surface on the inside of the tube. So that is what I did - over the strong objections of the tire repair shop manager saying this will never work.

I'll attach some pictures. I punched the new hole, then carefully enlarged it using a straight sided burr with my Dremmel tool to ensure there were no cuts that would tear when I forced the large end of the stem through the hole. I made the hole just large enough to accept the smaller diameter of the stem. This hole was much smaller than the one where the stem had been cut off. Then I injected liquid vulcanizing fluid (bought on the web in a small tube) alongside the stem so it would be forced onto the surface of the disk where it mates with the inside of the tube. I then installed the bridge washer and nut. It is now pressurized and holding so far, but only time will tell if it is actually leak free.

I still think there must be somebody out there that the stems could be sent to so they could be vulcanized to a patch for installation. I noted at the tire repair shop they used the same cold vulcanizing fluid to install the patch that I used, so maybe the industry thinks the cold fluid is just as good as the old hot vulcanizing. If that is the case, what I did is not too far from the original process except I installed the patch first and then inserted the stem. I could just as well have installed the stem into a patch, but I think that would be hard to align with a hole already in the tube. Maybe they cut a hole large enough to not be a problem aligning it. Not sure if I have the final answer, but this is where I am with it now.

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Alan,

Thank you very much for explaining your procedure and posting pictures. They sure do help us see and understand on how the stems are assembled to the tubes.

I gathered you tested the tubes for leaks before you installed them?

The stems for the wheels on my car come out straight per some of the old manufactor pictures I have seen. Sure hope when I order mine I don't have issues with them.

Please keep us posted on how yours hold up.

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AlanM, The only question I might have about moving the location of the stem is with the thickness of the tube in the new area. Where the stem was originally located, the tube is thicker and I imagine that it would therefore be more resistant to stretching out the hole where the stem penetrates as the tube is inflated up to pressure. The thinner tube material where you've relocated the hole might be more apt to stretch as the tube is inflated, pulling the rubber away from the stem. I don't know this to be a fact, just conjecture on my part.

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Pete O, You are correct. By moving the hole you are loosing the extra thickness in the area of the original rubber valve assembly. I had original NOS rubber inner tubes and the area where the metal stems were clamped into was reinforced by alternating layers of cloth fabric and rubber to give a solid clamping area. The correct way to use modern tubes with original or reproduction clamp in type valve hardware is to cut the rubber stem off above the surface of the inner tube. The remaining "stub" of the cut off rubber valve is then filed smooth and flush with the surface of the inner tube. What you will have remaining is the heavy reinforced area with a small hole that is the size of the inside of the rubber valve. I have had original tire valve hardware on my Model A Ford for over 20 years and on my 29' Dodge for 10. Rubber cement does not help seal rubber to metal. The easiest way to install the valve into the tube is to clamp the tube into a vise between 2 pieces of wood. You can then pull the tube to elongate the small hole and slip the metal valve into the elongated hole like buttoning a shirt. You may need to use a piece of coat hanger wire bent as a hook to stretch the hole. There has been a lot of discussion about the poor quality of inner tubes in the past few years. All of the tubes that I modified were of good quality.

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