BENDIX TCH-013-005 User Manual

Technical Bulletin

Bulletin No: TCH-013-005 Effective Date: 6/26/00 Cancels: NA Page: 1 of 3

Subject:

Bendix Commercial Vehicle Systems is reinforcing the importance of following proper installation and service
guidelines for installing, routing and securing whee l speed sensors, sensor cables and wire harnesses for Bendix
Antilock Braking Systems (ABS).

Bendix has discovered that if wheel speed sensor cables are not properly routed and secured, the cable could rub
on rotating components, causing damage which, in rare circumstances, could result in a temporary exhaust of
brakes for a few seconds at low speeds. Although this issue has only been reported on a small number of straight
trucks and buses, Bendix recommends that when servicing ABS, you ensure proper routing and securing of wheel
speed sensor cables.

Wheel Speed Sensor Cables

Wheel speed sensor cables coming directly out of the wheel ends should be routed at least 1.5 inches away from
moving components at all points and be properly secured to air lines and the axle to prevent excess cable slack
and potential chafing damage. Ensure that the wheel speed sensor cables attached along the length of the service
brake hoses are secured with tie wraps at intervals of approximately six (6) inches and are securely connected to
the wiring harness. In addition the wheel speed sensor cable should be secured with a tie wrap three (3) inches
from the sensor.

Wheel Speed Sensor Cable Chafing

Figure 1 - Photo of typical front wheel speed sensor cable installation

(View from Top)

Clamp

Tie Wrap 3 inches

from sensor

Tie Wraps

6 inches apart

Actuator

1.5 inch clearance at all points
from wheel or rotating

components with minim al

slack in cable

Tire

Wire Harness

Ensure all wiring routed along the frame rails is secured to frame members wherever possible. Secure every 12
inches throughout its length, preferably with non-metallic clamps or “Bow Tie” tie wraps. Route wires away
from sharp corners, heat sources, and moving or rotating components. If a harness is installed through a frame
member, grommets must be installed to prevent wire chafing. At all connectors, verify that the wires come out
straight for a minimum of three (3) inches before any bends. Be sure all connector seals are fully engaged in the
mating connector and secondary locks are snapped securely.

Figure 2 – Diagram of typical rear sensor routing and wire harness installation

Tie Wraps located

every 12 inches on

frame rail

Tie Wrap 3 inches

from sensor

1.5 inch clearance at all
points from wheels or

rotating components with

minimal slack in cable

Tie Wraps located

every 6 inches along

brake hose

As with all maintenance procedures before working on any vehicle follow the Safety Precautions outlined below.

IMPORTANT! PLEASE READ

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

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

2. Stop the engine when working around the vehicle.

3. If the vehicle is equipped with air brakes, make certain to drain the air pressure from all reservoirs before

beginning ANY work on the vehicle.

4. Following the vehicle manufacturer’s recommended procedures, deactivate the electrical system in a manner

that removes all electrical power from the vehicle.

5. When working in the engine compartment the engine should be shut off. 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.

6. 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.

7. Never exceed recommended pressures and always wear safety glasses.

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