 Many millions of valve
stems
were made, so they can often be found at swap meets.
Some of these were
priced at $2. Others were $3.
|
 Sometimes you find a
stem
with
the remains of an old tube still attached.
|
 |
These are the three most common valve stems. All are made by Schrader, by far the most common brand. Schrader #777 was used on tubes for Model T tires. It measures 3/8" by 3 1/8" (including the base). Even though the Model T was by far the most plentiful car of its time, this stem is relatively scarce compared to the others. Schrader #724 is one of the two most common stems. It measures ½" by 3 1/8". One side is marked with the Schrader number, and on the other side is TR-1. Schraeder #725 is the other most common stem. It measures ½" by 3 ¾". This is the size currently used on new metal stem tubes. One side is marked with the Schrader number, and on the other side is TR-2. |
 Let's convert a rubber
stem
tube
to a metal stem. The first step is to remove the rubber
stem. Cut it
near the base but not flush with the tube. You will find
a small brass
tube inside which extends down into
the tube. You have to pull out the brass tube, being
careful not to
split the rubber tube.
|
 Grind off the remains
of
the
rubber stem. You want to make a flat surface that will
be under the
bridge washer.
|
 Snap ring pliers are a
good
tool
to spread the hole so you can insert the stem. Note the
contact cement
slathered on top
of the stem base to help seal it agtainst the inside of the tube. |
 Spread the hole and
insert
the
base of the stem.
|
 With the stem in
the
hole
we're ready to install the hardware.
The flat sides of the stem should be parallel to the sides of the tire. |
 You want an original
style
bridge washer with a ridge that will press into the
rubber.
The new bridge washers are flat on the bottom. They're no good. |
 Put on the bridge
washer
and
tighten down the lock nut.
|
 After the tube and
tire are
mounted on the rim, the rim washer and the dust cover go
on. As the
diagram shows, the rim washer is actually a nut despite
the name. For
brass era stems
it's round and knurled. For nickel era stems it's
hexagonal.
|
 Brass era dust covers
available
today screw directly onto the stem.
Yes, it takes a lot of turning to put on or remove the cover. Sorry about that. |
 Many nickel era rim
washers
have
separate threads for the dust cover. There are many
different styles of
covers and rim washers.
|
 This is a common type of nickel era cover. |
 A cap inside the cover may prevent air loss if the valve develops a leak. |