SANDPIPER ST40 - Manual (Page 12)

st15dl4sm-rev0614 Models ST1½, ST40 Page 10
To re-install the sleeve and spool set, lightly lubricate the o-rings on the sleeve with
an o-ring assembly lubricant or lightweight oil (such as 10 wt. air line lubricant). Press
the set into the valve body easily, without shearing the o-rings. Re-install one end cap,
gasket and bumper on the valve body. Using the arbor press or bench vise that was used
in disassembly, press the sleeve back into the valve body. You may have to clean the
surfaces of the valve body where the end caps mount. Material may remain from the old
gasket. Old material not cleaned from this area may cause air leakage after reassembly.
Take care that the bumper stays in place allowing the sleeve to press in all the way.
Re-install the spool, the opposite end cap, gasket and bumper on the valve body.
After inspecting and cleaning the gasket surfaces on the valve body and intermediate,
re-install the valve body on the pump using new gaskets. Tighten the four hex head
capscrews evenly and in an alternating cross pattern.
PlLOT VALVE
This assembly is reached by removing the air distribution valve body from the pump
and lifting the pilot valve body out of the intermediate housing. Follow the instruction
above for the air distribution valve when servicing the pilot valve.
When reinserting an externally serviceable pilot valve, push both plungers out of the
path of the pilot valve so that they and the pilot valve are not damaged.
Service Note: If a problem arises with the pilot valve, it is usually corrected by
replacing only o-rings. Always grease the spool prior to inserting into the sleeve. If the
sleeve is removed from the body, reinsertion must be from the same side it was removed
from, the chambered side. Again, grease the o-rings so that it slides into the body. Make
sure the retaining ring has securely been inserted around the sleeve.
Service Note: When re-installing pilot valve (Item 6), make sure that plunger pins
(Item 5) are both pushed as far as possible in, toward the diaphragms. Large head as
close to casting as possible; otherwise, these items may be damaged.
PILOT VALVE ACTUATOR
The bushings for the pilot valve actuators are threaded into the intermediate bracket
from the outside. The plunger may be removed for inspection or replacement from the
inside by removing the air distribution valve body and the pilot valve body from the pump.
The plungers should be visible through the intermediate from the top. Depending on their
position, you may find it necessary to use a fine piece of wire to pull them out. Under
rare circumstances, it may be necessary to replace the o-ring seal.
To replace the o-ring, the bushing can be turned out through the inner chamber by
removing the outer chamber assembly to reach the bushing.
IMPORTANT
This pump is pressurized internally with air pressure during operation—always make
certain all bolting is in good condition and that all of correct bolting is reinstalled during
assembly.
WARRANTY
This unit is guaranteed for a period of five years against defective material and
workmanship.