Maintenance And Lubrication; Belt Changes - Bosch 4412 Operating/Safety Instructions Manual

Maintenance and Lubrication

Service
Preventive maintenance performed
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by unauthorized personnel may
result in misplacing of internal wires and components
which could cause serious hazard. We recommend
that all tool service be performed by a Bosch Factory
Service Center or Authorized Bosch Service Station.
Carbon Brushes
The brushes and commutator in your tool have been
engineered for many hours of dependable service. To
maintain peak efficiency of the motor, we recommend
every two to six months the brushes be examined.
Only genuine Bosch replacement brushes specially
designed for your tool should be used.
Motor Brush Replacement
To Inspect or Replace Brushes:
1. Unplug the saw.
The brush cap is spring loaded by
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the brush assembly.
2. Remove the brush cap on the motor using a wide
flat blade screwdriver.
3. Pull out the brush (Figure 39). Repeat for the
opposite side.
NOTE: If installing the existing brush or brushes,
make sure the brush goes in the same way it came
out. Otherwise a break-in period will occur that will
reduce motor performance and increase brush wear.
4. Inspect brushes for wear. On the wide flat side of
brush is a wear limit line. If the brush contact
face is at or beyond (no line visible) the limit
replace brushes as a set.
5. Install new brush. The two (2) tabs on the brush
terminal go in the same hole the carbon part fits
into.
6. Tighten the brush cap but do not overtighten.
Brush
Figure 39. Motor Brush
Brush
Terminal
32.
Drive Belt
The drive belt is a normal maintenance part and
should be inspected periodically for wear. If the drive
belt shows signs of drying out, cracking or tearing, it
should be replaced. If the drive belt will not track
properly or comes off the pulleys, it should be
replaced.
1. Installing new drive belt:
2. Loosen the two screws and remove the drive belt
cover.
3. Cut and remove the worn drive belt (Figure 40).
Before installing the new drive belt, clean both
pulleys thoroughly.
4. First place the new drive belt onto the drive pulley,
then rotate clockwise while pushing the belt onto
the driven pulley.
5. Reinstall the drive belt cover and securely tighten
screws.
Drive Belt
Driven Pulley
Figure 40. Belt Changes
Cleaning
To avoid accidents, always discon-
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nect the tool from the power supply
before cleaning or performing any maintenance. The
tool may be cleaned most effectively with com-
pressed air. Always wear safety goggles when clean-
ing tools with compressed air.
Ventilation openings and switch levers must be kept
clean and free of foreign matter. Do not attempt to
clean by inserting pointed objects through openings.
Check regularly to make sure the lower guard and all
moving parts are working properly.
Remove accumulated sawdust from working parts by
blowing with compressed air or wiping with a damp
cloth.
Certain cleaning agents and sol-
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vents damage plastic parts. Some
Drive Pulley