brakes MERCEDES-BENZ SPRINTER 2005 Service Repair Manual
[x] Cancel search | Manufacturer: MERCEDES-BENZ, Model Year: 2005, Model line: SPRINTER, Model: MERCEDES-BENZ SPRINTER 2005Pages: 1232, PDF Size: 39.23 MB
Page 1 of 1232
GROUP TAB LOCATOR
Introduction
0Lubrication & Maintenance
2Suspension
3Differential & Driveline
5Brakes
7Cooling
8AAudio/Video
8BChime/Buzzer
8EElectronic Control Modules
8FEngine Systems
8GHeated Systems
8HHorn
8IIgnition Control
8JInstrument Cluster
8LLamps
8NPower Systems
8ORestraints
8PSpeed Control
8QVehicle Theft Security
8RWipers/Washers
8WWiring
9Engine
11Exhaust System
13Frame & Bumpers
14Fuel System
19Steering
21Transmission
22Tires/Wheels
23Body
24Heating & Air Conditioning
25Emissions Control
Component and System Index
Service Manual Comment Forms (Rear of Manual)
Page 24 of 1232
HUB / BEARING
DIAGNOSIS AND TESTING -
(1) Raise and support the vehicle.
(2) Remove the grease cap.
(3) Position a dial indicator against the face of the
wheel hub (Fig. 3).
(4) Tighten the locking screw on the clamping nut
(Fig. 3).
(5) Pull the wheel hub firmly back and forth and
read off the wheel bearing play on the dial gauge.
(Wheel bearing play should be 0.02 - 0.04 mm
(0.000787 - 0.00158 in.).
(6) If necessary, loosen the locking screw and
adjust the wheel bearing play by loosing or tighten-
ing the clamping nut.
(7) Retighten the locking screw and recheck the
wheel bearing play.
REMOVAL
(1) Raise and support the vehicle.
(2) Remove the front wheels (Refer to 22 - TIRES/
WHEELS/WHEELS - REMOVAL).
(3) Remove the disc brake caliper adapter (Refer to
5 - BRAKES/HYDRAULIC/MECHANICAL/DISC
BRAKE CALIPER ADAPTER - REMOVAL).
(4) Remove the wheel flange ring (if equipped with
dual rear wheels) (Fig. 5).
(5) Remove the disc brake rotor (Refer to 5 -
BRAKES/HYDRAULIC/MECHANICAL/ROTORS -
REMOVAL).
(6) Remove the grease cap (Fig. 4).(7) Loosen the bolt on the clamping nut and
remove the clamping nut (Fig. 4).
(8) Remove the thrust washer (Fig. 4).
(9) Remove the wheel hub and tapered roller bear-
ing from the stub axle assembly (Fig. 4).
Fig. 2 LCA BUSHING INSTALL
1 - SPECIAL TOOL C-4212F (PRESS)
2 - SPECIAL TOOL 9302-1 (DRIVER)
3 - BUSHING
4 - SPECIAL TOOL 9302-2 (SIZER CUP)
5 - LOWER CONTROL ARM
6 - SPECIAL TOOL 9302-4 (RECEIVER CUP)
Fig. 3 MEASURING & ADJUSTING WHEEL BEARING
1 - WHEEL HUB
2 - LOCKING SCREW
3 - DIAL INDICATOR
Fig. 4 FRONT WHEEL HUB WITH SINGLE REAR
WHEELS (SRW)
1 - CALIPER ADAPTER BOLT
2 - DISC BRAKE CALIPER
3 - INNER BEARING
4 - WHEEL HUB
5 - DISC BRAKE ROTOR
6 - OUTER BEARING
7 - THRUST WASHER
8 - CLAMPING NUT
9 - GREASE CAP
10 - LOCKING BOLT
11 - GREASE SEAL
12 - STEERING KNUCKLE
2 - 4 FRONTVA
BUSHINGS (Continued)
Page 25 of 1232
INSTALLATION
(1) Install the wheel hub with the tapered roller
bearing on the stub axle (Fig. 4).
(2) Grease the outer tapered roller bearing thor-
oughly and push onto the steering knuckle (Fig. 4).
NOTE: The smooth side of the thrust washer must
point toward the wheel bearing.
(3) Install the thrust washer (Fig. 4).
(4) Install the clamping nut (Fig. 4). Tighten to 12
N´m (9 ft. lbs.) and then loosen a half of a turn.
(5) Check for wheel bearing end play. End play
should be 0.02- 0.04 mm (0.000787 - 0.00158 in.)
(Fig. 3) (Refer to 2 - SUSPENSION/FRONT/HUB /
BEARING - DIAGNOSIS AND TESTING).
(6) Pack the grease cap half with grease and coat
at the edge with sealant and install the cap (Fig. 4).
(7) Install the disc brake rotor (Refer to 5 -
BRAKES/HYDRAULIC/MECHANICAL/ROTORS -
INSTALLATION).
(8) Install the disc brake caliper adapter (Refer to
5 - BRAKES/HYDRAULIC/MECHANICAL/DISC
BRAKE CALIPER ADAPTER - INSTALLATION).
(9) Install the wheel flange ring (if equipped with
dual rear wheels) (Fig. 5).(10) Install the front tire & wheels assembly
(Refer to 22 - TIRES/WHEELS/WHEELS - INSTAL-
LATION).
(11) Lower the vehicle.
KNUCKLE
REMOVAL
(1) Raise and support the vehicle.
(2) Remove the front wheels (Refer to 22 - TIRES/
WHEELS/WHEELS - REMOVAL).
(3) Remove the disc brake caliper adapter (Refer to
5 - BRAKES/HYDRAULIC/MECHANICAL/DISC
BRAKE CALIPER ADAPTER - REMOVAL).
(4) Remove the hub/bearing (Refer to 2 - SUSPEN-
SION/FRONT/HUB / BEARING - REMOVAL).
(5) Separate the outer tie rod from the steering
knuckle (Fig. 6) using special tool C-3894±A.
(6) Raise the lower control arm approximately 10
mm using a jack.In order to eliminate tensile
force in the damper strut.
(7) Remove the ABS sensor from the knuckle by
pulling straight out.
(8) Remove the strut at the knuckle (Fig. 6).
(9) Separate the lower ball joint from the steering
knuckle using special tool 9282 (Fig. 6).
(10) Remove the steering knuckle from the vehicle
(Fig. 6).
INSTALLATION
(1) Install the steering knuckle on the lower ball
joint stud (Fig. 6).
Fig. 5 FRONT WHEEL HUB WITH DUAL REAR
WHEELS (DRW)
1 - ADAPTER BOLT
2 - DISC BRAKE CALIPER
3 - INNER BEARING RACE
4 - WHEEL HUB
5 - DISC BRAKE ROTOR
6 - LOCKING BOLT
7 - WHEEL FLANGE RING
8 - OUTER BEARING
9 - THRUST WASHER
10 - CLAMPING NUT
11 - GREASE CAP
12 - WHEEL FLANGE RING MOUNTING BOLT
13 - GREASE SEAL
14 - STEERING KNUCKLE
Fig. 6 STEERING KNUCKLE
1 - STRUT
2 - STRUT BOLT
3 - STEERING KNUCKLE
4 - LOWER BALL JOINT NUT
5 - OUTER TIE ROD END RETAINING NUT
6 - INNER TIE ROD END
7 - LOWER CONTROL ARM
VAFRONT 2 - 5
HUB / BEARING (Continued)
Page 26 of 1232
(2) Install the lower ball joint nut (Fig. 6). Tighten
to 280 N´m (206 ft. lbs.)
(3) Install the strut to the steering knuckle (Fig.
6). Tighten to 185 N´m (136 ft. lbs.).
(4) Install the outer tie rod end to the steering
knuckle (Fig. 6) and tighten the nut to 130 N´m (96
ft. lbs.).
(5) Install the ABS sensor by pushing the sensor
all the way into the knuckle and the sensor will self
adjust when the wheel is turned.
(6) Install the hub/bearing (Refer to 2 - SUSPEN-
SION/FRONT/HUB / BEARING - INSTALLATION).
(7) Install the disc brake caliper adapter with the
brake caliper (Refer to 5 - BRAKES/HYDRAULIC/
MECHANICAL/DISC BRAKE CALIPER ADAPTER -
INSTALLATION).
(8) Install the front wheels (Refer to 22 - TIRES/
WHEELS/WHEELS - INSTALLATION).
(9) Lower the vehicle.
(10) Check and set toe if necessary (Refer to 2 -
SUSPENSION/WHEEL ALIGNMENT - STANDARD
PROCEDURE).
LOWER BALL JOINT
REMOVAL
(1) Raise and support the vehicle.
(2) Remove the front tire and wheel assembly.
(3) Remove the front strut (Refer to 2 - SUSPEN-
SION/FRONT/STRUT - REMOVAL).
(4) Remove the steering knuckle (Refer to 2 - SUS-
PENSION/FRONT/KNUCKLE - REMOVAL).
(5) Remove the lower ball joint using special tool
9294-1 (Driver) with 9294-2 (Reciever) and C-4212±F.
(Fig. 7).
INSTALLATION
(1) Install the ball joint into the lower control arm
using special tool 9294-3 (Installer ring) inserted in
9294-2 (Reciever) and C-4212±F (Fig. 7).
(2) Install the front strut (Refer to 2 - SUSPEN-
SION/FRONT/STRUT - INSTALLATION).
(3) Install the steering knuckle (Refer to 2 - SUS-
PENSION/FRONT/KNUCKLE - INSTALLATION).
(4) Install the tire and wheel assembly (Refer to 22
- TIRES/WHEELS/WHEELS - INSTALLATION).
(5) Lower the vehicle.
(6) Check the front wheel alignment (Refer to 2 -
SUSPENSION/WHEEL ALIGNMENT - SPECIFICA-
TIONS).
LOWER CONTROL ARM
REMOVAL
(1) Insert spring blocks special tool 9288 between
the spring and the spring clamp plates, While the
vehicles wheels are on the ground.
(2) Raise and support the vehicle.
(3) Remove the front wheels (Refer to 22 - TIRES/
WHEELS/WHEELS - REMOVAL).
(4) Remove the disc brake caliper adapter (Refer to
5 - BRAKES/HYDRAULIC/MECHANICAL/DISC
BRAKE CALIPER ADAPTER - REMOVAL).Hang
the caliper. Do not allow brake hose to support
the caliper weight.
(5) Remove the retaining nut holding the tie rod to
the steering knuckle (Fig. 8).
(6) Seperate the tie rod off the steering knuckle
(Fig. 8) using special tool C-3894±A.
NOTE: In order to remove tension from the strut,
Raise the lower control arm approximately 10 mm
with a jack.
(7) Remove the strut bolts from the steering
knuckle (Fig. 8).
(8) Remove the stop plate bolts and rotate the
plate upwards with the stabilizer link attached (Fig.
8).
(9) Lower the lower control arm.
(10) Remove the lower ball joint nut from the
steering knuckle (Fig. 8).
(11) Separate the lower ball joint from the knuckle
using special tool 9282.
(12) Remove the lower control arm nuts and bolts
from the frame (Fig. 8).
(13) Remove the lower control arm.
INSTALLATION
(1) Install the lower control arm to the frame.
Hand tighten the nuts and bolts.
Fig. 7 LOWER BALL JOINT
1 - LOWER CONTROL ARM
2 - LOWER BALL JOINT
2 - 6 FRONTVA
KNUCKLE (Continued)
Page 27 of 1232
NOTE: In order to remove tension from the strut,
Raise the lower control arm approximately 10 mm
with a jack.
(2) Install the lower ball joint into the steering
knuckle. Tighten to 280 N´m (206 ft. lbs.).
(3) Install the strut bolts to the steering knuckle
(Fig. 8). Tighten to 185 N´m (136 ft. lbs.).
(4) Install the stop plate (Refer to 2 - SUSPEN-
SION/FRONT/SPRING STOP PLATES - INSTALLA-
TION).
(5) Lower the lower control arm.
(6) Attach the tie rod to the steering knuckle (Fig.
8). Tighten the nut to 130 N´m (96 ft. lbs.)
(7) Install the disc brake caliper adapter (Refer to
5 - BRAKES/HYDRAULIC/MECHANICAL/DISC
BRAKE CALIPER ADAPTER - INSTALLATION)
(Fig. 8).
(8) Install the front tire & wheel assembly (Refer
to 22 - TIRES/WHEELS/WHEELS - INSTALLA-
TION).
(9) Lower the vehicle.
(10) Remove the spring blocks between the spring
and the spring clamp plates, While the vehicles
wheels are on the ground.
(11) Roll the vehicle approximately 1 mm forwards
and the backwards, and rock firmly.(12) Tighten the lower control arm nuts and bolts
to the frame to 150 N´m (110 ft. lbs.) (Fig. 8).
(13) Apply brake to actuate brake pressure.
SPRING
REMOVAL
(1)To do this next step the vehicle must be
on the ground.Remove the front and rear bolts on
the left and right spring clamp plates (Fig. 9).
(2) Raise and support the vehicle.
(3) Remove the front wheels.
(4) Remove the brake caliper adapter (Refer to 5 -
BRAKES/HYDRAULIC/MECHANICAL/DISC
BRAKE CALIPER ADAPTER - REMOVAL).Do not
allow the caliper to hang by the hose, support
the caliper accordingly.
(5) Remove the ABS sensor from the mounting
bore in the steering knuckle (Fig. 9).
(6) Remove the outer tie rod retaining nut and
separate the tie rod from the knuckle (Fig. 9) using
special tool C-3894±A.
NOTE: In order to remove tension from the strut,
Raise the lower control arm approximately 10 mm
with a jack.
(7) Remove the strut bolts from the steering
knuckle.
(8) Remove both stop plate bolts and rotate the
plates upwards with the stabilizer link attached.
(9) Lower the lower control arm.
(10) Remove the lower ball joint nut from the
steering knuckle.
(11) Separate the lower ball joint from the knuckle
using special tool 9282.
(12) Remove the lower control arm nuts and bolts
from the frame.
(13) Remove the lower control arm from the frame
(Fig. 9).
NOTE: To avoid damaging the transverse leaf
spring, cushion the pad on the jack accordingly.
(14) Support the transverse leaf spring in the cen-
ter with a jack.
(15) Remove the left and right spring clamp plates
(Refer to 2 - SUSPENSION/FRONT/SPRING CLAMP
PLATES - REMOVAL) (Fig. 9).
NOTE: The upper spring blocks between the engine
cradle and the spring are color coded, Make sure
not to mix the blocks per sides. The blocks are dif-
ferent in sizes to accommodate the weight of the
vehicle and driver in order for the vehicle to sit
level.
Fig. 8 LOWER CONTROL ARM
1 - STRUT
2 - LOWER CONTROL ARM BOLT
3 - STOP PLATE BOLT
4 - STOP PLATE
5 - CALIPER ADPTER BOLT
6 - DISC BRAKE CALIPER
7 - LOCKING BOLT
8 - DISC BRAKE ROTOR
9 - OUTER TIE ROD END RETAINING NUT
10 - OUTER TIE ROD END
11 - LOWER BALL JOINT NUT
12 - LOWER BALL JOINT
13 - LOWER CONTROL ARM NUTS
14 - STRUT BOLT
VAFRONT 2 - 7
LOWER CONTROL ARM (Continued)
Page 60 of 1232
(2) Slide axle shaft into axle tube.
(3) Install axle shaft hub nuts and tighten to N´m
65 (48 ft. lbs.).
(4) Install wheels.
AXLE HUB BEARINGS/SEALS
REMOVAL
(1) Remove brake caliper with support.
(2) Remove axle shaft.
(3) Back-off parking brakes.
(4) Remove outer hub nut with Wrench 9290 (Fig.
19).
(5) Remove locking plate, inner hub nut and thrust
washer (Fig. 19).
(6) Pull hub off axle tube.
(7) Pry out ABS sensor and remove seal from hub
(Fig. 20).
(8) Remove hub bearings from hub (Fig. 21).
(9) Remove inner and outer bearing cups from hub
with a hammer and drift.
INSTALLATION
(1) Install hub bearing cups with Installer 9291
and a hammer.
(2) Clean and thoroughly grease bearings with
Multi-purpose grease.
(3) Install inner wheel bearing.
(4) Coat outer circumference ofnewseal with
Hylomar SQ 32 M sealant.CAUTION: Do not coat seals rubberized sealing sur-
faces with sealant.
(5) Install seal into hub with an appropriate
installer.
NOTE: Sealing ring should be flush with wheel hub
or max. 3mm (0.12 in.) deep.
(6) Coat contact surface of ABS sensor ring with
Hylomar SQ 32 M sealant.
Fig. 19 HUB NUTS
1 - NUTS
2 - LOCKING PLATE
3 - THRUST WASHER
Fig. 20 SENSOR RING & OIL SEAL
1 - ABS SENSOR RING
2 - SEAL
Fig. 21 AXLE HUB BEARINGS
1 - REAR BEARING
2 - HUB
3 - FRONT BEARING
4 - ROTOR
3 - 20 REAR AXLEVA
AXLE SHAFTS - DUAL REAR WHEELS (Continued)
Page 61 of 1232
(7) Drive ABS sensor ring ring in as far as the
stop with a plastic hammer.
(8) Install hub on axle tube.
(9) Install outer hub bearing (Fig. 22).
(10) Install thrust washer (Fig. 23).
(11) Install inner hub nut (Fig. 24).
(12) Tighten inner hub nut with Wrench 9290 to
300 N´m (221 ft. lbs.) while spinning the wheel hub
constantly. Turn back inner nut and then tighten
until it touches the thrust washer without play. Then
tighten 1/8 turn.
(13) Install locking plate (Fig. 25).(14) Install outer hub nut and tighten with
Wrench 9290 to 250 N´m (184 ft. lbs.).
(15) Install axle shaft.
(16) Install brake caliper and support.
(17) Adjust parking brakes.
Fig. 22 OUTER HUB BEARING
1 - HUB
2 - BEARING
Fig. 23 THRUST WASHER
1 - HUB
2 - WASHER
Fig. 24 INNER HUB NUT
1 - HUB
2 - NUT
Fig. 25 LOCKING PLATE
1 - HUB
2 - PLATE
VAREAR AXLE 3 - 21
AXLE HUB BEARINGS/SEALS (Continued)
Page 65 of 1232
BRAKES
TABLE OF CONTENTS
page page
BRAKES - BASE........................... 1BRAKES - ABS........................... 29
BRAKES - BASE
TABLE OF CONTENTS
page page
BRAKES - BASE
DIAGNOSIS AND TESTING - BASE BRAKE
SYSTEM.............................2
STANDARD PROCEDURE
STANDARD PROCEDURE - MANUAL
BLEEDING............................4
STANDARD PROCEDURE - PRESSURE
BLEEDING............................5
HYDRAULIC/MECHANICAL
SPECIFICATIONS
SPECIFICATIONS - TORQUE CHART.......5
BASE BRAKE.........................6
SPECIAL TOOLS
BRAKES.............................7
BRAKE LINES
STANDARD PROCEDURE
STANDARD PROCEDURE - ISO FLARING . . . 8
STANDARD PROCEDURE - DOUBLE
INVERTED FLARING....................8
BRAKE PADS/SHOES
REMOVAL
REMOVAL - FRONT (SRW)...............9
REMOVAL - FRONT (DRW)...............9
REMOVAL - REAR (16º WHEELS) (SRW)....9
REMOVAL - REAR (15º WHEELS) (SRW)....9
REMOVAL - REAR (DRW)...............10
INSTALLATION
INSTALLATION - FRONT (SRW)..........10
INSTALLATION - FRONT (DRW)..........11
INSTALLATION - REAR (16º WHEELS)
(SRW) ..............................11
INSTALLATION - REAR (16º WHEELS)
(SRW) ..............................11
INSTALLATION - REAR (DRW)...........11
DISC BRAKE CALIPERS
REMOVAL
REMOVAL - FRONT (SRW)..............11REMOVAL - FRONT (DRW)..............12
REMOVAL - REAR (SRW)...............12
REMOVAL - REAR (DRW)...............12
INSTALLATION
INSTALLATION - FRONT (SRW)..........12
INSTALLATION - FRONT (DRW)..........13
INSTALLATION - REAR (SRW)...........13
INSTALLATION - REAR (DRW)...........13
DISC BRAKE CALIPER ADAPTER
REMOVAL
REMOVAL - FRONT....................13
REMOVAL - REAR.....................13
INSTALLATION
INSTALLATION - FRONT................14
INSTALLATION - REAR.................14
FLUID
DIAGNOSIS AND TESTING - BRAKE FLUID
CONTAMINATION.....................14
STANDARD PROCEDURE - BRAKE FLUID
LEVEL..............................14
SPECIFICATIONS
BRAKE FLUID........................14
FLUID RESERVOIR
REMOVAL.............................15
INSTALLATION.........................15
ALB LEVER
REMOVAL.............................15
INSTALLATION.........................15
ALB CONTROLLER
REMOVAL.............................15
INSTALLATION.........................15
ADJUSTMENTS
ADJUSTMENT........................16
MASTER CYLINDER
DIAGNOSIS AND TESTING - MASTER
CYLINDER/POWER BOOSTER...........16
VABRAKES 5 - 1
Page 66 of 1232
STANDARD PROCEDURE - MASTER
CYLINDER BLEEDING..................17
REMOVAL.............................17
INSTALLATION.........................18
PEDAL
REMOVAL.............................18
INSTALLATION.........................19
POWER BRAKE BOOSTER
DESCRIPTION.........................19
OPERATION...........................19
REMOVAL.............................19
INSTALLATION.........................19
ROTORS
REMOVAL
REMOVAL - FRONT (SRW)..............19
REMOVAL - REAR (SRW)...............20
REMOVAL - FRONT (DRW)..............20
REMOVAL - REAR (DRW)...............20
INSTALLATION
INSTALLATION - FRONT (SRW)..........21
INSTALLATION - REAR (SRW)...........21
INSTALLATION - FRONT (DRW)..........21
INSTALLATION - REAR (DRW)...........21
SUPPORT PLATE
REMOVAL - REAR......................22
INSTALLATION - REAR...................22
PARKING BRAKE
SPECIFICATIONS
TORQUE CHART......................22SPECIAL TOOLS
PARK BRAKE........................23
CABLE TENSIONER
REMOVAL.............................23
INSTALLATION.........................23
CABLES
REMOVAL
REMOVAL - FRONT....................24
REMOVAL - REAR.....................24
INSTALLATION
INSTALLATION - FRONT................24
INSTALLATION - REAR.................25
ADJUSTMENTS
ADJUSTMENT - PARKING BRAKE CABLES . 25
LEVER
REMOVAL.............................26
INSTALLATION.........................26
SHOES
REMOVAL
REMOVAL - (SRW)....................26
REMOVAL - (DRW)....................26
CLEANING - REAR DRUM IN HAT BRAKE....27
INSTALLATION
INSTALLATION - (SRW).................27
INSTALLATION - (DRW).................27
ADJUSTMENTS
ADJUSTMENT........................27
BRAKES - BASE
DIAGNOSIS AND TESTING - BASE BRAKE
SYSTEM
Base brake components consist of the brake pads,
calipers, brake drum in hat rotor in the rear, rotors,
brake lines, master cylinder, booster, and parking
brake components.
Brake diagnosis involves determining if the prob-
lem is related to a mechanical, hydraulic, or vacuum
operated component.
The first diagnosis step is the preliminary check.
PRELIMINARY BRAKE CHECK
(1) Check condition of tires and wheels. Damaged
wheels and worn, damaged, or underinflated tires
can cause pull, shudder, vibration, and a condition
similar to grab.
(2) If complaint was based on noise when braking,
check suspension components. Jounce front and rear
of vehicle and listen for noise that might be caused
by loose, worn or damaged suspension or steering
components.(3) Inspect brake fluid level and condition. Note
that the brake reservoir fluid level will decrease in
proportion to normal lining wear.Also note that
brake fluid tends to darken over time. This is
normal and should not be mistaken for contam-
ination.
(a) If fluid level is abnormally low, look for evi-
dence of leaks at calipers, wheel cylinders, brake
lines, and master cylinder.
(b) If fluid appears contaminated, drain out a
sample to examine. System will have to be flushed
if fluid is separated into layers, or contains a sub-
stance other than brake fluid. The system seals
and cups will also have to be replaced after flush-
ing. Use clean brake fluid to flush the system.
(4) Check parking brake operation. Verify free
movement and full release of cables and pedal. Also
note if vehicle was being operated with parking
brake partially applied.
(5) Check brake pedal operation. Verify that pedal
does not bind and has adequate free play. If pedal
lacks free play, check pedal and power booster for
being loose or for bind condition. Do not road test
until condition is corrected.
(6) Check booster vacuum check valve and hose.
(7) If components checked appear OK, road test
the vehicle.
5 - 2 BRAKES - BASEVA
Page 67 of 1232
ROAD TESTING
(1) If complaint involved low brake pedal, pump
pedal and note if it comes back up to normal height.
(2) Check brake pedal response with transmission
in Neutral and engine running. Pedal should remain
firm under constant foot pressure.
(3) During road test, make normal and firm brake
stops in 25-40 mph range. Note faulty brake opera-
tion such as low pedal, hard pedal, fade, pedal pulsa-
tion, pull, grab, drag, noise, etc.
(4) Attempt to stop the vehicle with the parking
brake only and note grab, drag, noise, etc.
PEDAL FALLS AWAY
A brake pedal that falls away under steady foot
pressure is generally the result of a system leak. The
leak point could be at a brake line, fitting, hose, or
caliper/wheel cylinder. If leakage is severe, fluid will
be evident at or around the leaking component.
Internal leakage (seal by-pass) in the master cylin-
der caused by worn or damaged piston cups, may
also be the problem cause.
An internal leak in the ABS or RWAL system may
also be the problem with no physical evidence.
LOW PEDAL
If a low pedal is experienced, pump the pedal sev-
eral times. If the pedal comes back up worn linings,
rotors, drums, or rear brakes out of adjustment are
the most likely causes. The proper course of action is
to inspect and replace all worn component and make
the proper adjustments.
SPONGY PEDAL
A spongy pedal is most often caused by air in the
system. However, thin brake drums or substandard
brake lines and hoses can also cause a spongy pedal.
The proper course of action is to bleed the system,
and replace thin drums and substandard quality
brake hoses if suspected.
HARD PEDAL OR HIGH PEDAL EFFORT
A hard pedal or high pedal effort may be due to
lining that is water soaked, contaminated, glazed, or
badly worn. The power booster or check valve could
also be faulty.
PEDAL PULSATION
Pedal pulsation is caused by components that are
loose, or beyond tolerance limits.
The primary cause of pulsation are disc brake
rotors with excessive lateral runout or thickness vari-
ation, or out of round brake drums. Other causes are
loose wheel bearings or calipers and worn, damaged
tires.NOTE: Some pedal pulsation may be felt during
ABS activation.
BRAKE DRAG
Brake drag occurs when the lining is in constant
contact with the rotor or drum. Drag can occur at one
wheel, all wheels, fronts only, or rears only.
Drag is a product of incomplete brake shoe release.
Drag can be minor or severe enough to overheat the
linings, rotors and drums.
Minor drag will usually cause slight surface char-
ring of the lining. It can also generate hard spots in
rotors and drums from the overheat-cool down pro-
cess. In most cases, the rotors, drums, wheels and
tires are quite warm to the touch after the vehicle is
stopped.
Severe drag can char the brake lining all the way
through. It can also distort and score rotors and
drums to the point of replacement. The wheels, tires
and brake components will be extremely hot. In
severe cases, the lining may generate smoke as it
chars from overheating.
Common causes of brake drag are:
²Seized or improperly adjusted parking brake
cables.
²Loose/worn wheel bearing.
²Seized caliper or wheel cylinder piston.
²Caliper binding on corroded bushings or rusted
slide surfaces.
²Loose caliper mounting.
²Drum brake shoes binding on worn/damaged
support plates.
²Mis-assembled components.
²Long booster output rod.
If brake drag occurs at all wheels, the problem
may be related to a blocked master cylinder return
port, or faulty power booster (binds-does not release).
BRAKE FADE
Brake fade is usually a product of overheating
caused by brake drag. However, brake overheating
and resulting fade can also be caused by riding the
brake pedal, making repeated high deceleration stops
in a short time span, or constant braking on steep
mountain roads. Refer to the Brake Drag information
in this section for causes.
BRAKE PULL
Front brake pull condition could result from:
²Contaminated lining in one caliper
²Seized caliper piston
²Binding caliper
²Loose caliper
²Rusty caliper slide surfaces
²Improper brake pads
²Damaged rotor
VABRAKES - BASE 5 - 3
BRAKES - BASE (Continued)