Stihl TS 500i - Replacing the V-belt

44 TS 500i
: Push the suction hose (1) of
pump 0000 850 1300 onto the
connector (arrow)
6.2.2 Testing with negative
pressure
Oil seals tend to fail when subjected
to a vacuum. In other words, the
sealing lip lifts away from the
crankshaft during the piston's
induction stroke because there is no
internal counterpressure.
This kind of fault can be detected by
testing with pump 0000 850 1300.
During this test procedure, the oil
seals in the crankcase and in the
throttle shutter housing are
checked.
: Slide ring (1) to the left
: Operate lever (2) until the
pressure gauge (arrow) indicates
a vacuum of 0.5 bar
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If the vacuum reading remains
constant, or does not decrease
by more than 0.3 bar within
20 seconds, it may be assumed that
the oil seals are in good condition.
If the negative pressure continues
to drop, the leak must be located
and the faulty part replaced.
– If the oil seals in the crankcase
are defective, replace the oil
seals, b 6.3
– If the oil seals in the throttle
shutter housing are defective,
replace the throttle shutter
housing, b 11.2
– After testing, slide the ring on the
pump back to the right to vent the
pump
– Continue with pressure test,
b 6.2.3
6.2.3 Pressure test
The same preparatory steps are
required as for the vacuum test,
b 6.2.1.
– Before testing with gauge
pressure
– Complete testing with negative
pressure b 6.2.2
: Slide ring (1) to the right
: Actuate the lever (2) until the
pressure gauge (arrow) shows a
pressure of 0.5 bar. If this
pressure remains constant for at
least 20 seconds, the crankcase
is airtight.
– If the pressure drops, the leak
must be located and the faulty
part replaced.
To find the leak, coat the suspect
area with soapy water and
pressurize the crankcase. Bubbles
will appear if a leak exists.
– After testing, slide the ring on the
pump to the left to vent the pump
– disconnect the hose.
– Remove pressure testing tool
– Fit air filter, b 11.1
– Release the muffler and pull out
the sealing plate
– Tighten muffler according to
specifications, b 2.5
– Reassemble remaining parts in
reverse order
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