BENDIX SD-02-1302 User Manual

®

Clamp Ring (C)

Push Plate and Push 

Rod Assy.

Clamp Ring Nuts 

& Bolts

Center Inlet Port

Non-Pressure Plate (B)

Spring

Vent

Side Inlet Port

(shown plugged)

Pressure Plate (A)

Diaphragm

Push Plate

The brake chamber is a diaphragm-type actuator which 

converts the energy of air pressure into mechanical force. 

See Figure 2.  The diaphragm is held between the pressure 

plate (A) and non-pressure plate (B) by either a one- or  

two-piece clamp ring (C).

Different size brake chambers are identified by numbers 

which specify the effective area of the diaphragm.  For 

example, a brake chamber that has 30 square inches of 

“effective area” (the area of the diaphragm that generates 

force on the push plate), is commonly referred to as a type 

30 brake chamber.  See Figure 2.

Since one side of a brake chamber diaphragm is exposed to 

the applying air pressure and the other side to atmospheric 

pressure, the chamber has a pressure and a non-pressure 

side.  The non-pressure plate is usually vented to 

atmosphere by vent holes.  Installations where the chamber 

must be weather-proof, venting is accomplished through a 

variety of methods.  Consult the OEM for specific details.

The standard diaphragm material is a compound of natural 

rubber with a fabric interior of nylon. Neoprene-nylon 

diaphragms are optionally available.

Controlled air pressure enters the brake chamber through 

the inlet port and acts upon the diaphragm moving the push 

plate and rod assembly forward.

Lock Nut

Yoke

Mounting 

Bolts