Graco Husky 1590 DB3 Series Installation Manual page 19

4. Loosen but do not remove the diaphragm shaft bolts
(107), using a 15 mm socket wrench (1 in. on
stainless steel models) on both bolts. NOTE: This
step does not apply to pumps with overmolded
diaphragms.
5. Unscrew one bolt from the diaphragm shaft (24) and
remove the o-ring (108), fluid side diaphragm plate
(105), PTFE diaphragm (403, used on PTFE models
only), diaphragm (401), and air side diaphragm plate
(104). See F . 12.
IG
For overmolded diaphragms: Grip both diaphragms
securely around the outer edge and rotate
counterclockwise. One diaphragm assembly will
come free and the other will remain attached to the
shaft. Remove the freed diaphragm and air side
plate.
6. Pull the other diaphragm assembly and the
diaphragm shaft (24) out of the center housing (1).
Hold the shaft flats with a 19 mm open-end wrench,
and remove the bolt (107) from the shaft.
Disassemble the remaining diaphragm assembly.
For overmolded diaphragms: Pull the other
diaphragm assembly and the diaphragm shaft (24)
out of the center housing (1). Hold the shaft flats with
a 19 mm open-end wrench and remove the
diaphragm and air side plate from the shaft.
7. Inspect the diaphragm shaft (24) for wear or
scratches. If it is damaged, inspect the bearings (19)
in place. If the bearings are damaged, refer to page
21.
8. Reach into the center housing (1) with an o-ring pick
and hook the u-cup packings (402), then pull them
out of the housing. This can be done with the
bearings (19) in place.
9. Clean all parts and inspect for wear or damage.
Replace parts as needed.
Reassembly
1. Install the shaft u-cup packings (402*) so the lips face
out of the housing (1). Lubricate the packings. See
F . 12.
IG
2. Install the diaphragm assembly on one end of the
shaft (24) as follows. For pumps with overmolded
diaphragms, go directly to step g.
Service
a. Install the o-ring (108*) on the shaft bolt (107).
b. Install the fluid side diaphragm plate (105) on the
bolt so the rounded side faces in, toward the
diaphragm (401).
c. On PTFE models only, install the PTFE
diaphragm (403*). Make certain the side marked
AIR SIDE faces the center housing (1).
d. Install the diaphragm (401*) on the bolt. Make
certain the side marked AIR SIDE faces the
center housing (1).
e. Install the air side diaphragm plate (104) so the
recessed side faces the diaphragm (401).
f. Apply medium-strength (blue) thread locker to
the bolt (107) threads. Screw the bolt (107) into
the shaft (24) hand tight.
g. For overmolded diaphragms: Assemble the air
side plate (104) onto the diaphragm (403). The
wide, radiused side of the plate must face the
diaphragm. Apply medium-strength (blue) thread
locker to the threads of the diaphragm assembly.
Screw the assembly into the shaft (24) hand
tight.
3. Grease the length and ends of the diaphragm shaft
(24), and slide it through the housing (1).
4. Assemble the other diaphragm assembly to the shaft
as explained in step 2.
5. Hold one shaft bolt (107) with a wrench and torque
the other bolt to 20-25 ft-lb (27-34 Nm) at 100 rpm
maximum. NOTE: This step does not apply to pumps
with overmolded diaphragms.
6. Align the fluid covers (101) and the center housing
(1) so the arrows (A) on the covers face the same
direction as the air valve (B). Apply medium-strength
(blue) thread locker to the threads of screws (106)
and (112), and secure the covers with the screws
handtight. Install the longer screws (112) in the
bottom holes of the covers. See Fig. 11. Using a 13
mm socket wrench, torque the screws oppositely and
evenly to 190-220 in-lb (22-25 Nm). See Torque
Instructions, page 29.
7. Reassemble the ball check valves and manifolds as
explained on page 17.
308441ZAH 19