BRAK ES - ABS
TABLE OF CONTENTS
page page
BRAKES - ABS
SPECIFICATIONS - TORQUE CHART . . . . . . . . 30
ELECTRICAL
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 30
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
FRONT WHEEL SPEED SENSOR
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 31
REAR WHEEL SPEED SENSOR
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 32
TONE WHEEL
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 32
STEERING ANGLE SENSOR
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 32
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 33
LATERAL ACCELERATION SENSOR
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 33
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 34
YAW RATE SENSOR
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 35
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 36
HCU (HYDRAULIC CONTROL UNIT)
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 36
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 37
BRAK ES - ABS
SPECIFICATIONS - TORQUE CHART
TORQUE SPECIFICATIONS
DESCRIPTION N·m Ft. Lbs. In. Lbs.
Brake Lines To Hydraulic
unit
16 — 12
ELECT RI CAL
DESCRIPTION
NOTE: Wheel speed sensor should be installed all
the way into the clamping bushings, the wheel
speed sensor will self adjust when the vehicle is
moved.
The ABS bra ke system uses 4 wheel speed sensors.
A sensor is mount ed to each front hub/bear ings in
the front. A rear sensor is m ounted to each r ear sup-
por t plate.
OPERATION
The Wheel Speed Sen sor consist s of a magnet su r-
rounded by windings from a single strand of wire.
The sensor sends a small AC signal to the CAB. Th is
signal is gen erat ed by magnet ic induction. The mag-
netic in du ction is created when a toot hed sensor ring
(exciter ring or tone wheel) passes the sta tiona ry
magnetic WSS.
When the ring gea r is rot ated, the exciter ring
pa sses the tip of th e WSS. As the exciter rin g tooth
approach es the tip of the WSS, the magnetic lines of
force expa nd, ca using the m agnet ic field to cut across
the sensor’s windings. This, in tu rn cau ses current to
flow through the WSS cir cuit (Fig. 1) in on e direc-
tion. When th e exciter r ing t ooth moves awa y from
the sen sor tip, the m agnet ic lines of force collapse
cutting the winding in th e opposite dir ection . This
causes the current to flow in the opposite dir ection .
Ever y t ime a tooth of the exciter ring passes th e tip
of th e WSS, an AC sign al is generated. Each AC sig-
nal (positive to negat ive signa l or sinewa ve) is inter-
pr eted by th e CAB. It then compares the fr equen cy of
the sinewave to a time value to calcu late vehicle
speed. The CAB continues to mon itor th e frequency
5-30 BRAKES-ABS VA
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