Operation Manual

20 MS 241 C
5. Chain brake
5.1 Checking operation of
chain brake
The chain brake is one of the most
important safety devices on the
chain saw. Its efficiency is
measured in terms of the chain
braking time, i.e., the time that
elapses between activating the
brake and the saw chain coming to
a complete standstill.
Fouling (particularly with chain oil,
chips, fine particles of abrasion,
etc.) and smoothing of the friction
surfaces of the brake band and
clutch drum impair the coefficient of
friction. This in turn extends the
braking time. A fatigued or stretched
brake spring has the same negative
effect.
– Starting the engine
– With the chain brake
activated (locked), open the
throttle wide for a brief
period (max. 3 seconds) – the
chain must not rotate
– With the chain brake released,
open the throttle wide and
activate the brake manually – the
chain must come to an abrupt
stop
Versions with QuickStop Super
When the trigger interlock is
pressed, the clutch drum must
rotate freely.
With the coasting brake released,
open the throttle wide and release
the trigger interlock in the rear
handle – the saw chain must come
to an abrupt stop
All versions
The braking time is in order if
deceleration of the saw chain is
imperceptible to the eye (less than 1
second).
If the chain brake does not operate
properly, refer to the
troubleshooting chart, b 3.2.
5.2 Brake band
– Remove the clutch drum, b 4.1
– Troubleshooting, b 3.2
: Remove screws (1)
: Remove the cover (2)
– Block chain brake
: Unscrew screw (1) on the bottom
of the machine
2410RA006 TG
12
1
2410RA007 TG
1
2
: Ease brake band (2) out of
guide (arrow)
– Remove brake band, taking care
not to overextend it
– Release the chain brake
: Turn brake band (1) slightly aside
and disconnect it from the brake
lever (2)
Install a new brake band if there are
noticeable signs of wear on large
areas on the inside diameter and/or
parts of the outside (arrows) and its
remaining thickness is less than
< 0.6 mm.
5902RA024 TG
1
2
219RA049 TG