Displacement Pump Service
307427ZAF
31
Displacement Pump Service
STAINLESS STEEL DISPLACEMENT PUMPS, with rubber packings
This procedure covers the following displacement
pumps. Refer to the parts drawings on the indicated
pages for an illustration of your pump.
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Before You Start
1.
Disconnect the displacement pump from the air
motor as explained on page 11.
2.
Be sure you have all the necessary repair parts on
hand to reduce downtime.
3.
Repair Kit 218112 is available. For best results, use
all the new parts in the kit even if the old parts look
good.
Intake Valve
1.
Unscrew the intake valve housing (23) from the
cylinder (13), using a strap wrench. Disassemble
the valve and clean and inspect all parts.
2.
Inspect the ball (28) and seat in the housing (23) for
wear or nicks.
3.
Replace parts as necessary. Reassemble as shown
in the applicable parts drawing.
Piston Valve
1.
Using a strap wrench, grip the cylinder (13) near the
outlet housing (6) and unscrew it from the housing.
Pull the cylinder down off the piston. Check the
inner surface of the cylinder for scoring or wear by
running a finger over the surface or holding the part
up to the light at an angle.
2.
On Model 220440, loosen the lower nut (16) and
unscrew the valve housing (18) from the connecting
rod (17). Unscrew the piston stud (22).
On Model 220439, remove the cotter pins (29) from
the ball stop pin (30). Remove the ball stop pin and
unscrew the piston stud (22) from the displacement
rod (15). Be careful not to drop the ball (25).
3.
Clean and inspect all piston parts. Be sure to
inspect the ball (25) and its seat on the piston stud
(22) for wear or nicks. Replace parts as necessary.
Reassemble the piston parts as shown, being sure
that the lips of the u-cup packing (21) are facing up.
Torque as specified on the applicable illustration.
Using a strap wrench, grip the cylinder (13) near the
outlet housing (6) and screw it into the housing.
NOTE: On Model 220440, when reassembling the
piston to the connecting rod (17), screw the connecting
rod all the way into the displacement rod (15). Tighten
the upper nut (16) against the displacement rod and
torque to 33 N•m (24 ft-lb). Adjust the lower nut (16) to
allow 3.1 mm (0.125 in.) free travel for the ball (25).
Also, when installing the cylinder (13), make sure that
the knurled end is at the bottom.
Throat Packings
1.
Remove the cylinder (13) and piston as explained
previously. Remove the packing nut (1) and pull the
displacement rod (15) out of the top of the outlet
housing (6). Inspect the outer surface of the
displacement rod for scoring or wear by running a
finger over the surface or holding it up to the light at
an angle.
2.
Remove the throat packings from the outlet housing
(6).
3.
Clean and inspect the parts for wear or damage.
Lubricate the packings before reassembly. Install
the parts one at a time, in the same position as
before. The lips of the v-packings must face down
against fluid pressure.
4.
Leave the packing nut (1) loose until the
displacement rod (15) has been installed.
5.
Tighten the packing nut just enough to prevent
leaking. Overtightening can damage the packings.
6.
Reconnect the displacement pump to the air motor
as explained on page 11.
CAUTION
Insert the displacement rod from the top of the outlet
housing to prevent shearing of the packings.
