Bendix Commercial Vehicle Systems BEPA User Manual

Bendix® BEPA (Ford) 15" x 4" Cam Brake

SD-22-3250

FIGURE 1

GENERAL DESCRIPTION

The Bendix® BEP A (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.

OPERATION

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.

FIGURE 2 - BENDIX® BEPA (FORD) 15" X 4" CAM BRAKE

Key No. Description Qty.

1 Snap ring 1 2 Spacer washers # +reqd. 3 Yoke pin 1 4 Slack adjuster 1 5 Yoke 1 6 Cotter pin 1 7 Washer 1 8 Grease seal 2 9 Bushing 2 10 Cap screw 4 11 Lock washer 4 12 Chamber bracket and cam tube 1 13 Brake shoe assembly 2

Key No. Description Qty.

14 Cam roller assembly 2 15 Anchor pin 1 16 S-Cam shaft 1 17 Shoe return spring 1 18 Anchor spring 2 19 Spider 1 20 Dust shield 2 21 Rubber inspection plug 2 22 Cap Nut 6 23 Star Washer 6 24 Actuator 1 25 Mounting Nuts 2 26 Washers 2

PREVENTIVE MAINTENANCE 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.

1. BRAKE LUBRICATION Grease camshaft bracket with vehicle manufacturer’s

recommended chassis lube. Lube once every six months or at each chassis lubrication.

2. BRAKE RELINE The life of the brake lining is dependent on many factors

such as the material of the lining, type of operation the vehicle is used for, and the driver of the vehicle. If driving conditions require frequent braking, lining replacement will be required more often. Reline when lining thickness at center of shoe is 5/16". Refer to section “Reline Procedure”.

WARNING! PLEASE READ AND FOLLOW THESE INSTRUCTIONS TO A VOID PERSONAL INJURY OR DEATH:

When working on or around a vehicle, the following general precautions should be observed at all times.

1. Park the vehicle on a level surface, apply the parking brakes, and always block the wheels. Always wear safety glasses.

2. Stop the engine and remove ignition key when working under or around the vehicle. When working in the engine compartment, the engine should be shut off and the ignition key should be removed. Where circumstances require that the engine be in operation, EXTREME CAUTION should be used to prevent personal injury resulting from contact with moving, rotating, leaking, heated or electrically charged components.

3. Do not attempt to install, remove, disassemble or assemble a component until you have read and thoroughly understand the recommended procedures. Use only the proper tools and observe

all precautions pertaining to use of those tools.

4. If the work is being performed on the vehicle’s air brake system, or any auxiliary pressurized air systems, make certain to drain the air pressure from all reservoirs before beginning ANY work on the vehicle. If the vehicle is equipped with an AD-IS® air dryer system or a dryer reservoir module, be sure to drain the purge reservoir.

5. Following the vehicle manufacturer’s recommended procedures, deactivate the electrical system in a manner that safely removes all electrical power from the vehicle.

6. Never exceed manufacturer’s recommended pressures.

7. Never connect or disconnect a hose or line containing pressure; it may whip. Never remove a component or plug unless you are certain all

system pressure has been depleted.

8. Use only genuine Bendix® replacement parts, components and kits. Replacement hardware, tubing, hose, ﬁ ttings, etc. must be of equivalent size, type and strength as original equipment and be designed speciﬁ cally for such applications and systems.

9. Components with stripped threads or damaged parts should be replaced rather than repaired. Do not attempt repairs requiring machining or welding unless speciﬁ cally stated and approved by the vehicle and component manufacturer.

10. Prior to returning the vehicle to service, make certain all components and systems are restored to their proper operating condition.

11. For vehicles with Antilock Traction Control (ATC), the ATC function must be disabled (ATC indicator lamp should be ON) prior to performing any vehicle maintenance where one or more wheels on a drive axle are lifted off the ground and moving.

PREPARATION

1. Park vehicle on a level surface and prevent movement

by means other than the brakes.

2. If equipped with spring brakes, cage the spring on all

axles to be worked on.

3. Drain air from all reservoirs.

4. Raise the axle, to be worked on until the tires clear the

ground.

5. Turn the slack adjuster adjusting screw in the opposite

direction used to adjust the brakes until the cam rollers return to the start position on the S-cam.

6. Remove wheels and drums using the procedures

speciﬁ ed in the vehicle maintenance manual.

FIGURE 3 - REMOVING CAM ROLLERS

+ 5 hidden pages