Graco Inc. 308-501 Pressure Washer User Manual


 
18 308-489
PUMP
SER
VICE
WARNING
To reduce the risk of serious bodily injury ,
including
fluid injection, splashing in the eyes or
on
the skin, or injury from moving parts,
always
follow the Pressure Relief Procedure
Warning
before proceeding.
NOTE: The following metric wrenches are needed:
M10, M13 and M30. Repair kits are available.
Refer to the individual repair sections and the
pump
parts page for more details. For the best
results,
use all parts in the kits.
NOTE: There are two dif ferent tool kits to aid in
servicing the pump. P/N 800–298 is used to
ease installation of packings. P/N 800–271
includes
the items in 800–298
and tools to aid in
the
removal of packing retainers.
Valves
NOTE:
For a set of six valves, order P/N 801–472.
1. Remove
the hex plug from
the manifold using an M30
wrench.
2. Examine
the o–ring under the hex plug and replace it
if
it is cut or distorted.
3. Remove the valve assembly from the cavity; the
assembly
may come apart.
4. Install
the new valve. Install
the o–ring and hex plug;
torque
to 75 ft–lb (103 Nm).
NOTE:
Retorque the plug after 5 hours of operation.
Pumping Section
1. Remove
the eight capscrews and lockwashers
from
the
manifold using an M13 wrench.
2. Carefully
separate the manifold from the crankcase.
NOTE: It
may be necessary to tap the manifold lightly
with a soft mallet to loosen.
CAUTION
Keep the manifold properly aligned with the
ceramic plungers when removing to avoid
damage
to the plunger or seals.
3. Carefully examine each plunger for any scoring or
cracking
and replace as necessary
.
Servicing the Plungers
NOTE: Plunger repair kit,
P/N 801–474 is available to
replace retainers, o–rings, washers and
backup
rings for three cylinders.
1. Loosen
the plunger retaining screw five to six turns,
using
an M10 wrench. Push the plunger towards
the
crankcase to separate the plunger and retaining
screw.
2. Remove
the screw from the plunger and examine the
o–ring, backup ring and copper bearing/gasket
washer. Replace these parts if necessary using kit
801–474.
3. Remove the plunger and flinger from the plunger
shaft. Clean, examine and replace parts as
necessary.
4. Inspect the plunger shaft for oil leakage from the
crankcase.
If leaking is obvious, replace the oil seals.
Otherwise, DO NOT remove these seals as they
cannot be reused. An oil seal kit is available to
replace
the seals.
5. Lightly grease the flinger and oil seal, if it is being
replaced and replace them on the plunger shaft.
Then
install the plunger
.
6. Lightly
grease the retaining screw and the outer end
of the plunger
. Place the washer
, o–ring and backup
ring around the screw and install the screw through
the
plunger
. T
orque to 14.4 ft–lb (19.5 Nm).
NOTE: If you plan to replace the packings, refer to
Servicing
the V–Packings.
7. Lubricate the outside of each plunger . Slide the
manifold onto the crankcase, being careful not to
damage
the seals.
8. Install the capscrews and washers finger–tight.
Torque
the screws to 21.7 ft–lb (29 Nm) following the
tightening pattern (Figure 4). Uneven tightening may
cause
the manifold to bind or jam.
Figure 4
14
2
3
5
8
7
6