18 307-711
REPAIR INSTRUCTIONS
Repairs,
other than those
for which instructions are given
below,
should be performed by a trained and qualified re
-
pair
agency
.
WARNING
To
reduce the risk of serious injury
, including fluid in
-
jection, splashing
in the eyes or on the skin, or injury
from moving parts, always follow the Pressure Re-
lief Procedure Warning on page 11 before check-
ing
or repairing any part of the spray system.
Inlet Check V
alve
(See Fig 15)
1. Unscrew the inlet check valve (26) from the paint
pump (22).
2. Clean
the gasket (26a), the inlet valve (26), and the
paint
pump (22) threads and check for
erosion. If any
of
the parts are eroded, replace them.
3.
Be sure the threads in the paint pump are clean.
4. Lubricate the threads of the inlet valve with petro-
leum
jelly
. Install the gasket on the valve, then
install
the
valve and
torque it to 320–360 in–lb (36–41 N.m).
Outlet
Check V
alve
(See Fig 15)
1.
Unscrew the plug (28d) and the housing (28b).
2. Use a pick, such as a dentist’s pick, to remove the
seal (28a) from the paint pump (23). It may be hard
to remove.
DO NOT LEAVE THE SEAL IN THE
PAINT
PUMP HOUSING.
3. Clean the parts thoroughly, including the threads in
the
pump, with a compatible solvent.
Check all parts
for
wear or damage and replace as needed.
4.
Lubricate the threads of the housing (28b) and plug
(28d).
5. Install a NEW seal (28a) in the pump housing. AL-
WAYS
replace
the seal (28a). Do not try to reuse the
old
seal as it will be deformed.
CAUTION
Be
sure you do not install a new seal until the old one
is
removed. Having two seals in the valve will cause
performance
problems.
6. Install
the housing (28b) and torque to 125–150 in–lb
(14–17
N.m) .
7. The last coil on one end of the spring is turned in.
Place
this end over the stud in the plug (28d). Install
the ball (28e), washer (28f) and plug, and torque to
plug
to 380–300 in–lb (32–34 N.m).
Pressure Control
(See Fig 15)
1. When
removing the pressure
control (4) to check or
clean
it, always replace the seal (4a). When replac
-
ing the pressure control, torque the new control (4)
to
125–150 in–lb (14–17 N.m).
Starter Switch
(See Fig 15)
1. Remove
the cover of the switch box.
Remove the two
screws
holding the starter switch (18a). Remove
the
old
switch and install a new one.
Diaphragm
(See Fig 15)
1. Remove
the
inlet strainer (27). Remove the four paint
pump
screws (25) and lockwashers (24).
2. Remove the bypass valve (66) and the fluid outlet
nipple (67), and then remove the screws (35) and
shield (3).
3. Remove
the
screw (36) and lockwasher (37) from the
bracket (38).
4. Pull
the paint pump assembly away
from the hydrau
-
lic
housing (20) and remove the old diaphragm
(21).
CAUTION
Never
start the electric motor with the inlet valve (26)
removed,
as it
will severely damage the diaphragm.
Be
careful not to get any dirt or paint on the new dia
-
phragm or the hydraulic housing. Contaminants in
the hydraulic system can cause the sprayer to mal-
function
and result in costly damage to the sprayer
.
DO
NOT T
AMPER with the nut (C). The nut is factory
set
to hold the spring to a specific dimension.
CAUTION
5. Check
the gasket (22a) for wear or damage and
re
-
place it if needed. Clean the top of the paint pump
and
the hydraulic housing thoroughly
.
6. Install the new diaphragm assembly (21), lubricate
the internal threads of the housing (20), and reas-
semble
the parts.
7. Lubricate
the screws (25)
and then install and torque
them
to 170–200 in–lb (19–23 N.m ).
CAUTION
Whenever you remove the paint pump screws,
torque
them as instructed above,
and then retorque
them
after 3 to 5 hours of operation.
8. Check the hydraulic oil level and add Graco-ap-
proved
oil as necessary until the level is 1 in. (25 mm)
from
the top of the plate. See Fig 1
1.
9. Turn the pressure control fully counterclockwise
(no
pressure). Plug in the sprayer and turn it on. Run
the sprayer for two minutes to fill the hydraulic sys-
tem.
Increase the pressure to maximum
and turn the
sprayer
on and of
f
four times to help rid the hydraulic
system
of air
.
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