Keiser Keiser 300, Parts And Maintenance Manual

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3. Rest the valve housing on the open jaws of a vise and drive out the spring pin with a
hammer and 3/16-drift punch (see illustration below). When the punch is removed,
the spool can be removed as shown.
4. Remove the O-rings off the spool. CAUTION : DO NOT CUT SPOOL! CUTS IN A
SPOOL ARE AREAS FOR POSSIBLE AIR LEAKS. Wipe the spool completely
dry with a clean dry cloth and inspect it carefully for signs of wear or deterioration.
Lightly coat the narrow part of the spool with silicon lubricant and slip on three new
O-rings.
5. Clean the inside passages of the valve housing with solvent and compressed air. Do
not use any kind of tool inside the housing. Inspect the bore for scratches or wear of
any kind. The housing should be replaced if there are any imperfections in the bore.
6. Assembly is the opposite of disassembly. Tap the spring pin into the spool until it is
just flush with the outside of the housing.
7. For increase valves, push the air hose from the filter over the barb on the high-
pressure side of the valve (see illustration), and the air hose to the manifold on the
low-pressure side. Push the hose all the way up to the flange. For decrease valves,
the air hose from the manifold is connected to the high pressure side, and the air hose
from the muffler is connected to the low pressure side.