Graco PGM Instructions - Parts Manual page 45

PGM-20 Pump Disassembly
1. Prepare Gear Meter Assembly for Repair,
page 35.
2. Refer to Gear Pump Maintenance Guide on
page 47 for special notes regarding gear pump
repair.
3. Remove six pump block shoulder bolts (4).
Pump section should be fully supported to prevent
damage being dropped. It is recommended that the
gear meter assembly be located on a work bench for
service.
4. Remove drive assembly. See F
Thicker materials may require heating prior to disas-
sembly. Do not expose the pump to thermal shock.
Raise temperature at a maximum rate of 180°F
(100°C) per hour. Do not exceed 400°F (204°C).
Exceeding this temperature could promote leakage in
the pump. Gradually cool the pump to room tempera-
ture.
5. Remove seal retainer fasteners (1515) seal retain-
ers (1512), spacers (1510) and (1511).
6. Remove pump dowels (1509) using an arbor press.
Do not use a hammer to remove dowel pins as this
will damage the pump.
7. Remove the pump plate screws (1514).
8. Separate the pump front plate (1501), gear case
(1502) and back plate (1503).
NOTE: Notches on the pump plates can be used to
separate the plates.
9. To remove drive shaft (1504) from the drive gear
(1506) several flat spacers 1/8 in. (3 mm) thick will
3A5185B
NOTICE
. 23.
IG
NOTICE
NOTICE
be needed. These will provide clearance for the
drive shaft key (1508) and the top plate (1501).
10. Support pump top plate (1501) and press drive shaft
(1504) through drive gear (1506). Stop when there
is enough clearance between the drive gear (1506)
and top plate (1501) to insert one spacer. Be sure to
allow clearance for drive key (1508).
11. Continue pressing the drive shaft (1504) and insert-
ing spacers until the shaft is free from the drive gear
(1506).
12. The stud (1505) for the driven gear (1507) is press
fit into the back plate (1503) and need not be
removed if not worn.
The PGM pump design relies on a lap fit between
components for performance and sealing. Be careful
not to drop the gears (1607, 1608) or damage the
mating surfaces of the pump plates (1601, 1603) and
gear case (1602). To prevent damage, do not use pli-
ers or screwdrivers to remove the gears.
13. Clean all components thoroughly before reassem-
bly. The use of an ultrasonic cleaner is recom-
mended.
NOTICE
Repair
45