Graco Python A25011, Instructions - Parts Manual

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Repair
3A4386E 29
Replace Air Motor Seal
1. Remove the air piston o-ring (7) with a plastic pick
from the air piston (6), taking great care not to
scratch any of the groove surfaces on the piston.
2. Clean any debris or buildup from the piston (6) and
plunger (5) assembly, as well as the air piston cylin-
der (8) and return spring (4).
3. Apply a liberal amount of assembly grease to the
new air piston o-ring (7), and slide it over the piston
(6) and into the groove.
Fluid Plunger Replacement
1. Use the wrench flats (see F
IG
. 14) located on the
piston (6) and plunger (5) to loosen and remove the
plunger from the piston.
2. Clean the dried thread locker from the internal
threads of the piston (6) as much as possible.
3. Apply a thin bead of high strength thread locker to
the external threads of the new plunger (5).
4. Install the new plunger and tighten to 75 in-lbs
(8.5 N•m).
5. Allow thread locker to dry for 60 minutes before
operating the pump.
Air Piston, Fluid Plunger, and Upper
Cylinder Reassembly
1. Ensure that all parts are cleaned before reassem-
bly.
2. Apply a thin coat of grease to the inside of the air
piston cylinder (8) and piston o-ring (7), and insert
the piston (6) and plunger (5) assembly.
3. Apply a light coat of assembly grease to the end of
the plunger (5), making certain the tip is fully coated.
4. Place the return spring (4) inside the piston stop (2).
5. Reconnect the air piston cylinder (8) to the air motor
housing (1). Carefully guide the fluid plunger (5) into
the packing nut (16) and through the packing as the
air piston cylinder is brought closer to the air motor
housing. Light pressure is required to keep the air
piston cylinder in place. Ensure the cylinder (8) is
F
IG
. 14 Air piston and fluid plunger
Wrench Flats
7
6
5
F
IG
. 15 Reassemble air piston
8
10
6
5
4
1
7