C8 Maintenance    8. Joint #4 
 
C Series Maintenance Manual Rev.2  347 
7.  Remove the Joint #4 pulley 1 and the drive boss from the motor 
shaft of the Joint #4 motor unit. 
Pulley 1 and drive boss screws 
Hexagon socket set screws: 2-M4×4 (with a brass bushing) 
Drive boss and motor shaft screws 
Hexagon socket set screws: 2-M4×4 
 
There is a brass bushing on one of the set screws fixing the drive 
boss and the pulley. Be careful not to lose it. 
A: Pulley and motor shaft screws 
B:  Pulley and drive boss screws 
C:  Bushing 
Pulley 
Drive boss 
A 
A 
C 
B 
 
 
 
 
 
 
 
8.  Remove the Joint #4 electromagnetic brake. 
Hexagon socket set screws: 3-M3×15 (with a spacer) 
Be careful not to lose the spacers. 
9.  Remove the motor plate from the Joint #4 motor. 
Hexagon socket head cap bolts: 2-M4×10