BENDIX BW1458 User Manual

The Bendix

®

 BEPA (Ford) 15" x 4" cam brake is designed 

for use on heavy duty highway vehicles. It is a mechanically 
actuated, leading/trailing shoe brake with a fi xed position 
cam and anchor.

The brake consists of two fabricated steel shoe assemblies 
anchored to a cast iron torque spider and actuated by a 
single forged S-cam shaft. Two retaining springs secure 
the shoe assemblies to the anchor pin. The twin webs of 
each shoe assembly are keyed to the anchor pin on one 
end and the cam roller on the other. A single shoe to shoe 
return spring is used to maintain constant contact between 
the shoe, cam roller and cam.

The Bendix

®

 cam brake operates in the following manner 

during a braking application. The force of the push rod of 
the actuator is converted from a linear force to a rotary 
torque. This is accomplished by use of the slack adjuster. 
This torque is transferred to the cam shaft of the foundation 
brake due to the spline of the cam shaft being connected to 
the gear of the slack adjuster. On the opposite end of the 
cam shaft is the S-cam which when rotated lifts the cam 
rollers. This spreads the brake shoe ends apart equally and 
pivots the shoes about the anchor pin so the brake lining 
comes in contact with the rotating brake drum. The friction 
created by the lining pressure against the drum generates 
the torque necessary to provide a retarding force to slow 
down the vehicle. The energy of the vehicle in motion is 
converted to heat at the surface of the drum and lining. 
This heat raises the temperature of the drum. The heat is 
stored in the drum, and fi nally dissipated to the air.