Oil Seals - Stihl MS 290 Manual

If the vacuum reading remains
constant, or rises to no more than
0.3 bar within 20 seconds, it can be
assumed that the oil seals are in
good condition.
However, if the pressure continues
to rise (reduced vacuum in the
crankcase), the oil seals must be
replaced.
– After finishing the test, open the
vent screw and disconnect the
hose.
– Remove the test flange.
Install in the reverse sequence.
MS 290, MS 310, MS 390
6.3

Oil Seals

It is not necessary to disassemble
the complete engine if only the oil
seals have to be replaced.
Clutch side
– Remove the clutch, b 5.5
– Remove the oil pump, b 10.4.1
1
: Apply puller (1) 5910 890 4400
with No. 3.1 jaws 0000 893 3706.
– Clamp the puller arms.
– Pull out the oil seal.
Take care not to damage the
crankshaft stub.
– Clean sealing face with standard
solvent-based degreasant
containing no chlorinated or
halogenated hydrocarbons,
b 13.
2
1
If the engine has not been
disassembled, only the so-called
"soft" oil seal 9639 010 1743 may
be installed.
: Place the oil seal (2) in position
with the clamping ring (1) facing
up.
– Lubricate sealing lip of oil seal
with grease, b 13.
– Apply thin coating of sealant to
the outside diameter of the oil
seal,
b 13.
If the engine has been dis-
assembled and the engine pan
removed, it is recommended that
the "hard" oil seal 9639 003 1743
be installed in place of the soft oil
seal 9639 010 1743 before the
engine pan is refitted.
Important:
Do not use a press to install the
hard oil seal 9639 003 1743.
Install hard oil seals as described in
b 6.7
Install in the reverse sequence.
27