Repair; Pressure Relief Procedure; Disassembly - Graco A Series Instructions - Parts Manual

Repair

Repair
• Packing repair kit 247881 is available. Use all of the
parts in the kit for the best results. Kit parts are indi-
cated with an asterisk, for example, (3*)
• Have all necessary repair parts on hand. Recom-
mended spare parts are indicated in the parts list
with a checkmark, for example (2✓).
• The throat and piston packing stacks (11* and 12*)
are preassembled. Do not disassemble the stacks
when you install them.
• Use light, waterproof grease wherever lubrication is
indicated.

Pressure Relief Procedure

Trapped air can cause the pump to cycle unexpectedly,
which could result in serious injury from splashing or
moving parts.
1. Engage the trigger lock.
2. Close the bleed-type master air valve to shutoff the
pump.
3. Disengage the trigger lock.
4. Hold a metal part of the gun firmly to a grounded
metal pail. Trigger the gun to relieve pressure.
5. Engage the trigger lock.
6. Open all fluid drain valves in the system, having a
waste container ready to catch drainage. Leave the
drain valve(s) open until you are ready to spray
again.
7. If you suspect the spray tip or hose is clogged or
that pressure has not been fully relieved after follow-
ing the steps above, VERY SLOWLY loosen the tip
guard retaining nut or hose end coupling to relieve
pressure gradually, then loosen completely. Clear
the hose or tip obstruction.
4

Disassembly

1. Flush the pump, if possible. Stop the pump at the
bottom of its stroke. Relieve the pressure, page 4.
2. Disconnect the displacement pump from the air
motor as described in Hydra-Clean package manual
312585.
3. See the Parts drawing on page 6. Unscrew the four
tie bolts (7) and remove the intake valve housing (6).
4. Disassemble the intake valve, taking note of the
position of the ball stop pin (5). Inspect the ball (4)
and seat for nicks and scratches.
5. Pull the cylinder (2) straight off the outlet housing
(1), being careful not to scratch or damage the pol-
ished inner wall. Remove the o-rings (3).
6. Loosen the packing nut/wet-cup (15). Pull the dis-
placement rod (8) out the bottom of the outlet hous-
ing (1).
7. Inspect the polished inner surface of the cylinder (2)
and the outer surface of the displacement rod (8) for
scoring or scratches which can damage the pack-
ings.
8. Unscrew the piston body (13) from the displacement
rod (8). Disassemble the piston. Inspect the ball (4)
and seat for nicks or scratches. If you remove the
ball stop pin (9), take note of which set of holes it
was installed in.
9. Unscrew the packing nut/wet-cup (15). Remove the
bearing (14) from the packing nut. Remove the
throat packings (12) from the outlet housing (1).
10. Use a compatible solvent to clean parts. Inspect
parts for wear or damage and replace parts as
needed.
312745A