Bendix Commercial Vehicle Systems TABS-6 TRAILER ABS MODULE - Manual (Page 5)

5
FIGURE 6 - BENDIX ® WS-24 ™ WHEEL SPEED SENSORS
90° Speed
Sensors
Straight Speed
Sensors
Sensor
Clamping
Sleeve
1. For increased corrosion protection we recommend
that a high-temperature rated silicon- or lithium-based
grease be applied to the interior of the mounting block,
the sensor, and to a new clamping sleeve.
2. Install the new clamping sleeve fully into the block,
with the retaining tabs toward the inside of the vehicle.
Please note that WS-24
™ wheel speed sensors must
use the correct clamping sleeve to avoid problems
associated with reduced retention force, such as sensor
movement and resulting ABS trouble codes.
3. Gently push (DO NOT STRIKE) the sensor into the
mounting block hole until it bottoms out on the face of
the tone ring. Secure the cable lead wire to the knuckle/
axle housing 3-6 inches from the sensor.
4. Apply a moderate amount of dielectric non-conductive
grease to both the sensor connector and harness
connector.
5. Engage the connectors, and push together until the
lock tab snaps into place.
NOTE: It is important for the wheel bearings to be
adjusted per the manufacturer's recommendations.
The friction fi t allows the WS-24 ™ sensor to slide back and
forth under force but to retain its position when the force
is removed. When the WS-24
™ sensor is inserted all the
way into the mounting block and the wheel is installed on
the axle, the hub exciter contacts the sensor, which pushes
the sensor back. Also, normal bearing play will “bump” the
sensor away from the exciter. The combination of these
two actions will establish a running clearance or air gap
between the sensor and exciter.
Excessive wheel end play can result in diagnostic trouble
codes in cases where the sensor is pushed too far away
from the tone ring.
BENDIX ® BR9235 ™ ABS
MODULATOR RELAY VALVES
Bendix ® BR9235 ™ modulator relay valves (MRV) are
required when additional modulator relay valves are
needed for multichannel brake systems (e.g. 2S/2M, 4S/3M
ABS confi gurations).
The MRV is an electro-pneumatic control valve and is the
last valve that air passes through on the way to the brake
chambers. The normally-open hold solenoid and normally-
closed exhaust solenoid are activated to precisely modify
the brake pressure on command. During normal braking,
the BR9235
™ MRV functions as a standard relay valve. As
brakes are applied or released by the driver, the control
signal from the tractor foot valve causes the BR9235
™ MRV
to apply proportional pressure to the trailer brake chambers.
The BR9235 ™ MRV is available in both tank and bracket
mounting styles.
BENDIX ® WS-24 ™ WHEEL SPEED SENSORS
Wheel speed data is provided to the TABS-6 module from
the WS-24
™ wheel speed sensors (see Figure 6). Vehicles
have an exciter ring (or “tone ring”) as part of the wheel
assembly, and as the wheel turns, the teeth of the exciter
ring pass the wheel speed sensor, generating an AC signal.
The TABS-6 module receives the AC signal, which varies in
voltage and frequency as the wheel speed changes. (The
default setting expects a 100-tooth tone ring to be used.)
Vehicle axle and ABS control confi gurations determine if
two or four wheel speed sensors are required. See page
17 for electrical system schematics showing wheel speed
sensor connector pin locations.
A proper sensor installation is critical to correct ABS
operation.
Typically, the WS-24 ™ sensor is installed in mounting blocks
that are welded to the axle housing. WS-24 ™ wheel speed
sensors are protected by a stainless steel sheath. They
are designed to be used with beryllium copper clamping
sleeves (sometimes referred to as a “retainer bushing”,
“friction sleeve” or “clip”) (See Figure 6). The clamping
sleeve provides a friction fi t between the mounting block
bore and the WS-24
™ sensor.
Logo Stamped
into Sleeve
FIGURE 7 - BENDIX ® BR9235 ™ MODULATOR RELAY
VALVE
3-Pin Modulator
Solenoid
Connector
3/8" NPT Supply
Port with Integral
Filter
Four 3/8" NPT Delivery Ports
(to Brake Chambers)