Operating instructions
12
PTFE Slide Ring Replacement
(6a) The Teflon rings should be examined for scuffing and wear. If replacement is
necessary they should be fitted before the seals. A length of Teflon should be cut so
that there is a small gap between the ends when it is wrapped around the piston
groove. The piston should then be pushed into the receiving tube over its entire
length of travel. Should any tight spots be revealed, the PTFE should be thinned
down slightly with a sharp knife or abrasive paper, taking care to keep the thickness
as even as possible. This procedure should continue until the piston slides freely.
Piston replacement
When the mast is dismantled, the pistons should not be removed. They are fitted
during manufacture by heat shrinking the tube onto the piston, in the event of
removing the piston; they cannot be secured by the same system. It should be noted
that the smaller tubes have the extra security of screws into the piston spigot âFâ and
this must be used to refit a piston.
After removing the seal and PTFE ring, coat the piston spigot âFâ with a sealing
compound and insert into the tube. Drill two holes and countersink for the screw
head, clear away all swarf and fit self-tapping screws. Should air leaks be evident,
use further sealer on the screw heads and around the piston where it meets the end
of the tube.