Stihl MS 461 - 5 Chain Brake; Checking Operation; Brake Band

19MS 461, MS 461-R
5. Chain Brake
5.1 Checking Operation
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.
Contamination (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,
which prolongs the braking time. A
fatigued or stretched brake spring
has the same negative effect.
– Start 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.
The braking time is in order if
deceleration of the saw chain is
imperceptible to the eye (a fraction
of a second).
If the chain brake does not operate
properly, refer to troubleshooting,
b 3.2.
5.2 Brake Band
– Troubleshooting, b 3.2
– Remove the clutch drum,
: Take out the screw (1) and
remove the side plate (2).
: Take out the screws (1).
: Remove covers (2) and (3).
2
3443RA051 TG
1
3443RA052 TG
2
1
1
1
3
– Engage the chain brake
– Brake band no longer
tensioned in its seat.
: Take out the screw (1).
: Ease the brake band (2) out of its
seat (arrow) and lift it away.
Do not overstretch the brake band.
– Disengage the chain brake.
– the brake band can be
disconnected when the brake
lever is in this position.
: Turn the brake band (1) to one
side and disconnect it from the
brake lever (2).
3443RA023 TG
2
1
3443RA024 TG
1
2