Installing Metal Valve Stems in Rubber Stem Tubes

This example shows the installation of Model A reproduction valve stems into rubber tubes for 4.75x19 tires. The same approach has been used to install original metal stems into tubes for 30x3.5" Model T clincher tires. (This is just the way I do it - use it at your risk :-) )

Note that this example shows a tube that has an extremely difficult to remove brass tube. Other tubes can be cut off almost flush with the bottom of the valve stem and then skip these first few steps. When you try the first tube you will find if the type you have are a problem. In this example the longer stub of a valve stem is used to have something to be able to be gripped by the pliers to twist it out (if cut off too close to the base there is nothing to grab with the pliers). If you have the type of tube where there the brass tube just ends in the rubber instead of having a flared out base securely attached you can just go around the base of the stem with a knife (not cutting through the brass) and then twist the stem out with your hand. That type of stem leaves a smoother hole also. Hopefully this will all be clear when looking at the pictures...



0 - Cut off the stem about a 1/4" from the bottom.
metal stem 0
1 - This leaves a stub with the (now crushed) brass tube in the center.
metal stem 1
2 - Slice around the base with knife close to the base (the easier the stem comes out the closer that it can be cut to the base).
metal stem 2
3 - Cut away the rubber.
metal stem 3
4 - Brass tube is now left.
metal stem 4
5 - Twist the brass tube out. Cut around the edge if needed, but the goal is to leave the inside of the hole as round and smooth as possible.
metal stem 5
6 - The brass tube is now removed.
metal stem 6
7 - Trim close to the base. These multiple extra cutting steps are not necessary if the brass tubes are easy to remove and don't want to tear up the tube on the way out.
metal stem 7
8 - Try to end up with something reasonably flat, close to the surface of the tube.
metal stem 8
9 - Use a file or whatever you prefer to smooth it.
metal stem 9
10 - The final result after filing it smooth.
metal stem 10
11 - I use snap ring pliers to open up the hole. Others have used two hooks mounted in a vice to pull on either side of the hole to pull it open.
metal stem 11
12 - Don't be afraid to stretch it open.
metal stem 12
13 - These pliers open it up just enough to get the stem started in the hole.
metal stem 13
14 - Once the stem is in the hole the pliers can be removed to finish inserting the stem.
metal stem 14
15 - The stem is in the hole and the tube is snugged up right against the stem.
metal stem 15
16 - Put on the bridge washer. The ridges in the stem base and the bridge washer are enough to seal the air from coming out. I don't use any sealant because I don't know what will be compatible with the rubber but the results have been fine reusing old stems on clincher tires which get inflated to 65 lbs/psi. I have seen sealant on some old stems and might have used some bead sealer if I had some handy.
metal stem 16
17 - Put on the nut.
metal stem 17
18 - Tighten down the nut. I've heard some people express concern about making it too tight and squeezing out the rubber from between the washer and the base but I don't see that happening when I get it good and tight by hand.
metal stem 18
19 - Make sure the stem and washer stay in line with the tube and don't turn as they are tightened.
metal stem 19
20 - Put in a new Schrader valve (particularly if using old stems).
metal stem 20
21 - Tighten the valve with the cap.
metal stem 21
22 - Put the cap on - it is now ready to mount on the wheel.
metal stem 22
Questions or comments? Send mail to John Carter: cars @ sheepisland.com (remove the spaces).