BENDIX SD-02-4500 User Manual

®

The Bendix Piggyback Spring Brake is made up of a
conventional brake chamber and an emergency or parking
spring mechanism for use on vehicles equipped with cam
foundation brakes.  The Spring Brake Actuator provides:  (1)
Service Braking, (2) Parking and (3) Emergency Braking.
The actuator can be piped with various system arrangements
to be automatically or manually applied under emergency
braking conditions.

The spring brake is a diaphragm type actuator which converts
the energy of air pressure into mechanical force. The
diaphragm is held between the pressure plate and non-
pressure plate by a two piece clamp ring.

Different size brake chambers are identified by numbers
which specify the effective area of a diaphragm. For example,
a Type 30/30 Spring Brake has 30 square inches of effective
area on each diaphragm.

The standard diaphragm material is a compound of natural
rubber with a fabric interior of nylon.

PIGGYBACK CHAMBER

SERVICE PUSH-ROD

SERVICE

CHAMBER

SERVICE

DIAPHRAGM

Important:  Review the warranty policy before performing
any intrusive maintenance procedures. An extended warranty
may be voided if intrusive maintenance is performed during
this period.

Because no two vehicles operate under identical conditions,
maintenance intervals will vary. Experience is a valuable guide
in determining the best maintenance interval for a vehicle.

Every 300 operating hours, 8,000 miles, or one (1) month:

1. Check push rod travel and adjust travel at the slack

adjuster if needed. Push rod travel should be as short
as possible without the brakes dragging. Excessive push
rod travel reduces braking efficiency, shortens diaphragm
life, gives slow braking response and wastes air.