Displacement Pump Service - Graco Dura–Flo Instructions-Parts List Manual

DISPLACEMENT PUMP SERVICE

Disassembly
When disassembling the pump, lay out all the removed
parts in sequence, to ease reassembly. Clean all parts
with a compatible solvent and inspect them for wear or
damage. Refer to Fig. 8.
NOTE: Repair Kits are available to replace the throat (T)
and piston (P) packings, and to replace the o-rings and
cylinder seals. For the best results, use all the new parts
in the kit. Kit parts are marked with an asterisk, for
example (8*). These kits can also be used to convert the
pump to different packing materials. Refer to pages 29
and .
1. Stand the displacement pump upright in a large
vise. Loosen, but do not remove, the packing nut
(3). Remove the six long cap screws (20) and
washers (33, if present), using a socket wrench.
2. Lift the outlet housing (19) straight up off the pump.
Be careful not to scratch the displacement rod (1)
while removing the housing.
3. Lift the cylinder (7), displacement rod (1), and piston
assembly off the intake housing (17).
4. Remove the seal (6), ball guide (14), intake ball (16),
intake seat housing (15), and o-ring (31) from the
intake housing (17). Inspect the ball (16) and the ball
seat (A) on the housing (15) for wear or damage.
5. Remove the seal (6) from the bottom of the outlet
housing (19). Unscrew the packing nut (3). Re-
move the glands and v-packings (T) from the
housing. Do not remove the outlet fitting (4) and
o-ring (5) unless they need replacement.
6. Unscrew the bleeder valve plug (33) completely
from the valve body (32). Clean the valve threads
and the bleed hole. It is not necessary to remove the
valve body from the pump outlet housing (19).
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Service
7. Stand the cylinder (7) upright on a wooden block.
Using a rubber mallet or an arbor press, drive the
displacement rod (1) and piston assembly down into
the cylinder as far as possible, then place the
cylinder on its side and continue to drive the rod out
the bottom until the piston comes free. Pull the rod
and piston from the cylinder, being careful not to
scratch the rod or cylinder.
To reduce the possibility of costly damage to the rod
(1) and cylinder (7), always use a rubber mallet or an
arbor press to drive the rod out of the cylinder. Be sure
to place the cylinder on a soft block of wood. Never
use a hammer to drive the rod.
NOTE: Service Tool 109508 is available as an
accessory. The tool fits over the top of the displacement
rod (1), making it easier to apply a 24 inch adjustable
wrench or 3/4 in. drive socket when disconnecting the
rod from the piston assembly.
8. Put the flats of the piston seat housing (12) in a vise.
Unscrew the rod (1) from the housing (12), leaving
the ball guide (9) assembled to the rod. Be careful to
catch the piston ball (10) as you separate the
housing (12) and ball guide (9), so that it doesn't fall
and suffer damage.
9. Remove the glands and v-packings (P) from the
piston seat housing (12). Inspect the ball (10) and
ball seat (B) on the housing (12) for wear or
damage.
10. Inspect the outer surface of the displacement rod (1)
and the inner surface of the cylinder (7) for scoring
or wear; replace either part if necessary. If the rod is
being replaced, remove the ball guide (9) as
explained in step 11.
NOTE: Do not remove the ball guide (9) from the
displacement rod (1) unless either part is damaged.
11. Place the flats of the ball guide (9) in a vise. Using a
24 in. adjustable wrench or 3/4 in. drive socket,
unscrew the rod (1) from the ball guide.
CAUTION