Komatsu PC88MR-10 Shop Manual page 505

sealing surface of filter cartridge (1), and then
tighten it 1/4 to 1/2 turn.
a If the transparent cup is fastened too much,
the O-ring will be damaged and this leads to
leakage of fuel. If it is too loose, fuel will also
leak from gaps of the O-ring. Therefore, be
sure to observe the fastening angle.
10.Clean the filter head, fill the new filter cartridge
with clean fuel, thinly apply oil to the packing
surface, then install it to the filter head.
a Be sure to add fuel through 8 small holes (A)
on the dirty side without removing center cap
(B).
a After adding fuel, remove cap (B) and install
the fuel filter.
a Fuel for adding should be clean fuel. Be
careful to prevent any dirt or dust form
entering into it. In particular, center portion is
the clean side, so do not remove cap (B)
when adding fuel. Be careful to prevent dirt
or dust from entering into the center clean
side part.
11.When installing the cartridge, tighten it until the
packing surface contacts the sealing surface of
the filter head, then tighten it 3/4 of a turn.
a If the filter cartridge is fastened too much, the
packing will be damaged and this leads to
leakage of fuel. If the filter cartridge is too
loose, fuel will also leak from the packing.
Therefore, be sure to observe the fastening
angle.
a When using a filter wrench for tightening,
take care not to leave flaws or dents on the
filter.
12.Make sure that drain valve (4) is securely
closed.
13.Set valve (6) to OPEN position (O).
14.After completing the replacement of filter
cartridge (1), bleed air according to the following
procedure.
1) Fill up the fuel tank with fuel (to the level
where the float is at the highest position).
PC88MR-10
Related information on troubleshooting
2) Loosen the knob of fuel feed pump (8), pull it
out, then pump it in and out until the
movement becomes heavy.
15.After bleeding air, push in the knob of fuel feed
pump (8) and tighten it.
16.After replacing filter cartridge (1), start the
engine and run it at low idle for 10 minutes.
17.Check the filter seal surface and the mounting
face of the transparent cap for fuel leakage. If
there is any leakage of fuel, check the fastening
condition of the filter cartridge. If the fuel still
leaks, follow Steps 3) to 7) to remove the filter
cartridge, then check the packing surface for
damage or foreign material. If any damage or
foreign material is found in the packing, replace
the cartridge with a new one, then repeat steps
8) to 16).
a10. Check of main filter
Immediately after the engine is stopped, its
parts and oil are still very hot, and may cause
burn injury. Accordingly, wait until all parts
have cooled down before starting the work.
High pressure is generated inside the engine
fuel piping system when the engine is
running. Stop the engine and wait at least 30
seconds until the inner pressure is released
and then replace the filter.
Never bring open flames near fuel.
a A special filter with high-efficiency filtering
properties is adopted for Komatsu genuine fuel
filter cartridges. Be sure to use Komatsu
genuine parts when replacing.
a The common rail fuel injection system used on
this machine consists of more precise parts than
those in the conventional injection pump and
nozzles. If any cartridge other than a Komatsu
genuine fuel filter cartridge is used, foreign
material may enter, and it may cause problems
in the injection system. Do no use substitute
parts.
a During testing or maintenance of the fuel system,
take extreme care not to allow any foreign
material to enter the fuel system. If any dust or
other material sticks to any part, wash the part
thoroughly with clean fuel.
Prepare a container to receive drained oil.
Prepare a filter wrench.
1. Open inspection cover (1).
40 Troubleshooting
40-17