wheel torque CHEVROLET DYNASTY 1993 Owner's Manual

REAR WHEEL DRUM BRAKES INDEX
page page
Brake Drum Refacing ..................... 21
Brake Shoe Assemblies ................... 19 Description
............................. 18
Service Procedures ....................... 18
DESCRIPTION
Rear wheel drum brakes (Fig .2&3)aretwoshoe,
internal expanding type with an automatic adjuster
screw assembly that is activated each time the
brakes are applied. The automatic adjuster screw is
located directly below the wheel cylinder as shown in
figure (Fig .2&3).
WARNING: DUST AND DIRT ON BRAKE PARTS
GENERATED DURING THE NORMAL USE AND
WEAR OF MOTOR VEHICLE BRAKE SYSTEMS MAY
CONTAIN ASBESTOS FIBERS. BREATHING EXCES-
SIVE CONCENTRATIONS OF ASBESTOS FIBERS
CAN CAUSE SERIOUS BODILY HARM, SUCH AS
ASBESTOSIS AND CANCER. EXTREME CARE
SHOULD BE EXERCISED WHILE SERVICING
BRAKE ASSEMBLIES OR COMPONENTS. DO NOT CLEAN BRAKE ASSEMBLIES OR COM-
PONENTS WITH COMPRESSED AIR OR BY DRY
BRUSHING; USE A VACUUM CLEANER SPECIFI-
CALLY RECOMMENDED FOR USE WITH ASBES-
TOS FIBERS. IF A SUITABLE VACUUM CLEANER IS
NOT AVAILABLE, CLEANING SHOULD BE DONE
WET USING A WATER DAMPENED CLOTH. DO NOT CREATE DUST BY SANDING, GRINDING,
AND/OR SHAVING BRAKE LININGS OR PADS UN-
LESS SUCH OPERATION IS DONE WHILE USING
PROPERLY EXHAUST VENTILATED EQUIPMENT. DISPOSE OF ALL DUST AND DIRT SUSPECTED
TO CONTAIN ANY ASBESTOS FIBERS IN SEALED
BAGS OR CONTAINERS TO MINIMIZE DUST EXPO-
SURE TO YOURSELF AND OTHERS. FOLLOW ALL RECOMMENDED PRACTICES PRE-
SCRIBED BY THE OCCUPATIONAL SAFETY AND
HEALTH ADMINISTRATION AND THE ENVIRON-
MENTAL PROTECTION AGENCY. FOR THE HAN-
DLING, PROCESSING, AND DISPOSITION OF DUST
OR DIRT WHICH MAY CONTAIN ASBESTOS FI-
BERS. IT IS RECOMMENDED NOT TO BREATH ANY
TYPE OF BRAKE LINING MATERIAL DUST EVEN
ASBESTOS FREE, DUE TO THE FIBROUS NATURE
OF THE MATERIALS BEING USED.
SERVICE PROCEDURES
REAR BRAKE DRUM REMOVAL
If the rear brake drum is difficult to remove, fur-
ther clearance can be obtained by backing off the
brake automatic adjuster screw. Remove rubber plug
from the top of the support plate and rotate the au-
tomatic adjuster screw assembly with an upward mo-
tion, using the Brake Adjuster, Special Tool C-3784. See adjusting rear service brakes in the Service
Adjustments section in this group of the service man-
ual for the specific adjustment procedure. Remove wheel bearing grease cap (Fig. 1).
Remove cotter pin, nut lock, retaining nut, thrust
washer and outer bearing cone (Fig. 1). Remove brake drum and hub and bearing assembly
from the rear spindle (Fig. 1). Inspect brake linings for wear, shoe alignment and
contamination.
BRAKE DRUM INSTALLATION
Install brake drum and hub and bearing assembly
on rear spindle. Install outer wheel bearing, thrust washer and nut.
Tighten wheel bearing adjusting nut to 27 to 34
N Im (240 to 300 in. lbs.) torque while rotating hub.
This seats the bearings. Back off adjusting nut 1/4 turn (90É) then tighten
adjusting nut finger tight. Position lock on nut with one pair of slots in-line
with cotter pin hole. Install cotter pin.
Fig. 1 Brake Drum and Hub Assembly
5 - 18 BRAKES Ä

Install grease cap and wheel and tire assemblies.
Tighten wheel stud nuts to 115 N Im (85 ft. lbs.)
torque on all models. Install wheel covers.
BRAKE SHOE ASSEMBLIES
Three brake shoe assemblies are used on the front
wheel drive passenger cars. Vehicles will have axle
sets of either 200 or 220 mm Kelsey Hayes (Fig. 2),
or Varga (Fig. 3). Varga brake shoes are HANDED
for right or left side. Except for brake shoe to support plate, park brake
lever retention and automatic adjuster positioning
guide buttons, service procedures for either assembly
are essentially the same.REMOVAL
Remove automatic adjuster spring and lever (Fig.
4).
Rotate the automatic adjuster screw assembly so
that each shoe assembly moves out far enough to be
free from the wheel cylinder boots (Fig. 5).
Disconnect the parking brake cable from the park-
ing brake lever (Fig. 6).
Fig. 2 Kelsey Hayes 200 And 220 (Left) Rear Wheel Brake
Fig. 3 Varga (Left) Rear Wheel Brake
Fig. 4 Remove or Install Adjuster Lever Spring
Fig. 5 Expand or Retract Adjuster Screw
Ä BRAKES 5 - 19

BRAKE SUPPORT ASSEMBLY
REMOVAL
Back off parking brake adjusting nut to provide
slack in cable. With wheel and brake drum removed, disconnect
hydraulic tube from wheel cylinder.Disconnect park-
ing brake cable and adjuster lever spring (Fig. 1).
Using a suitable tool such as an aircraft type hose
clamp, install the clamp over the retainer on the end
of the parking brake cable (Fig. 2). Compress cable
housing retainer and start housing out of support
plate (Fig. 2). Remove clamp when retainer is free
from the park brake cable mounting hole in the rear
brake support plate. Alternate method is to slide a
14 mm box wrench over housing end fitting com-
pressing the three fingers. Remove attaching bolts and washers and separate
brake support and spindle from rear support trailing
arm.
INSTALLATION
Insert parking brake cable and housing into sup-
port plate. Install support plate, spindle and gasket between
support plate and spindle on to rear suspension mem-
ber. Tighten support plate attaching bolts to 71 N Im
(53 ft. lbs) torque. Attach cable to parking brake lever.
Connect brake tube to wheel cylinder. Tighten
brake tube to wheel cylinder fitting to 17 N Im (145
in. lbs.). Install brake drum and wheel. Adjust and bleed
service brakes. Adjust parking brake.
Fig. 1 Removing Adjuster Lever Spring
Fig. 2 Removing Park Brake Cable From Support Plate
Ä BRAKES 5 - 25

material, (Fig. 7). Be sure inboard brake shoe assem-
bly is correctly positioned against anti-rattle clip
(Fig. 6). (4) Reinstall the Braking Disk on the hub, by in-
stalling it over the wheel studs until it is seated
against the face of the hub (Fig. 6). (5) Slide the new outboard brake shoe assembly on
the adapter abutment, (Fig. 5). (6) Carefully lower caliper over the braking disk and
brake shoe assemblies (Fig. 3). Make sure that the
caliper guide pin bolt, bushings and sleeves are clear of
the adapter. (7) Install the caliper guide pin bolts and tighten to
34 to 37 N Im (25 to 35 ft. lbs.). Extreme caution
should be taken not to cross the threads of the
caliper guide pin bolts. (8) Install the wheel and tire assembly. Tighten the
wheel mounting stud nuts in proper sequence (Fig. 9)
until all nuts are torqued to half specification. This is
important. Then repeat the tightening sequence to the
full specified torque of 129 N Im (95 ft. lbs.).
(9) Remove jackstands or lower hoist. Before mov-
ing vehicle, pump the brake pedal several times
to insure the vehicle has a firm brake pedal to
adequately stop vehicle. .
(10) Road test the vehicle and make several stops to
wear off any foreign material on the brake linings and
to seat the brake shoe linings.
Fig. 8 Remove Or Replace Anti-Rattle Clip
Fig. 9 Tightening Wheel Nuts
Ä BRAKES 5 - 37

iper, by installing retaining clip into the bore of the
piston (Fig. 5).
CAUTION: Use care when installing the caliper as-
sembly onto the steering knuckle, so the seal on the
sealed for life bushings does not get damaged.
(5) Carefully lower caliper over braking disc and
guide holddown spring under machined abutment on
knuckle assembly (Fig. 8).
(6) Install caliper guide pin bolts and tighten to
24-34 N Im (18-25 ft. lbs.) torque. When installing guide pin bolts, use extreme caution not to cross
thread the guide pin bolts.
(7) Install wheel and tire assembly. Tighten stud
nuts in proper sequence until all nuts are torqued to
half specification. This is important. Then repeat
sequence to full specification. (8) Remove jackstands or lower hoist. Before mov-
ing vehicle be sure it has a firm pedal, pump
pedal several times. (9) Road test vehicle and make several stops to
wear off any foreign material on the brakes and
to seat the linings.
DISC BRAKE CALIPER DISASSEMBLY
CLEANING AND INSPECTION
Check for piston fluid seal leaks (brake fluid in and
around boot area and inboard lining) and for any
ruptures of piston dust boot. If boot is damaged, or fluid
leak is visible, disassemble caliper assembly and in-
stall a new seal and boot,(and piston if scored). Refer to
procedures titled Disc Brake Caliper Disassembly. Check the caliper dust boot and caliper pin bushings
to determine if they are in good condition. Replace if
they are damaged, dry, or found to be brittle. Refer to
Cleaning And Inspection Of Brake Caliper. (1) Remove caliper from braking disc (See Brake
Shoe Removal). Hang assembly on a wire hook away
from braking disc, so hydraulic fluid cannot get on
braking disc (See Fig. 3 in Brake Shoe Removal). Place
a small piece of wood between the piston and caliper
fingers. (2) Carefully depress brake pedal to hydraulically
push piston out of bore. (Brake pedal will fall away
when piston has passed bore opening.) Then prop up
the brake pedal to any position below the first inch of
pedal travel, this will prevent loss of brake fluid from
the master cylinder. (3) If both front caliper pistons are to be removed,
disconnect flexible brake line at frame bracket after
removing piston. Plug brake tube and remove piston
from opposite caliper. Using the same process as above
for the first piston removal.
WARNING: UNDER NO CONDITION SHOULD AIR
PRESSURE BE USED TO REMOVE PISTON FROM
CALIPER BORE. PERSONAL INJURY COULD RE-
SULT FROM SUCH A PRACTICE.
(4) Disconnect brake flexible hose from the caliper.
To disassemble, mount caliper assembly in a vise
equipped with protective jaws.
CAUTION: Excessive vise pressure will cause bore
distortion and binding of piston.
Fig. 7 Installing Outboard Shoe Assembly onto Cali- per
Fig. 8 Guiding Holddown Spring Under MachinedAbutment
5 - 40 BRAKES Ä

each brake shoe assembly is returned to its origi-
nal position on the wheel of the vehicle from
which it was removed. (2) Install inboard brake shoe by inserting shoe
retaining clip into piston cavity. Be sure brake shoe is
seated squarely on the face of the piston. (Fig. 5). (3) Install outboard shoe by sliding retaining clip
over caliper fingers. Be sure the brake shoe is installed
on the caliper, so the retaining clip is past the raised
area on the caliper fingers (Fig. 6). (4) Install lower end of caliper on to adapter. Make sure the lower tabs on the brake shoes and the cast-
ing projections on the caliper are under the adapter
rail (Fig. 7). (5) Rotate caliper down over rotor.
(6) Install caliper attaching bolts and tighten to 22
N Im (193 in. lbs.) torque (Fig. 8).
(7) Install wheel and tire assembly. Tighten stud
nuts in proper sequence until all nuts are torqued to
half specification. This is important. Then repeat
sequence to full specification. (8) Remove jackstands or lower hoist. Before mov-
ing vehicle be sure it has a firm pedal.
Fig. 5 Remove and Install Inboard Brake Shoe
Fig. 6 Installing Outboard Shoe
Fig. 3 Removing Caliper
Fig. 4 Removing Outboard Shoe
Ä BRAKES 5 - 47

knuckle. Position stem so it contacts hub face near
outer diameter. Care must be taken to position stem
outside the stud circle but inside the chamfer on the
hub rim. Clean hub surface before checking. (See
Fig. 3)
Runout should not exceed 0.08 mm (0.003 inch). If
runout exceeds this specification, hub must be re-
placed. See Suspension Group 2. If hub runout does
not exceed this specification, install disc on hub with
chalk marks two wheel studs apart (Fig. 4). Tighten
nuts in the proper sequence and torque to specifica-
tions. Finally, check runout of disc to see if runout is
now within specifications. If runout is not within specifications. Install a new
braking disc or reface disc, being careful to remove
as little as possible from each side of disc. Remove
equal amounts from each side of disc. Do not reduce
thickness below minimum thickness cast into the un-
machined surface of the rotor. Thickness variation measurements of disc should
be made in conjunction with runout. Measure thick-
ness of disc at 12 equal points with a micrometer at
a radius approximately 25.4 mm (1 inch) from edge
of disc (Fig. 5). If thickness measurements vary by
more than 0.013 mm (0.0005 inch) disc should be re-
moved and resurfaced (Figs. 6 and 7), or a new disc
installed. If cracks or burned spots are evident in the
disc, disc must be replaced. Light scoring and/or wear is acceptable. If heavy
scoring or warping is evident, the disc must be refin-
ished or replaced (See Refinishing/Refacing Braking
Disc). If cracks are evident in the disc, replace the
disc.
BRAKING DISC REMOVAL
(1) Raise vehicle on hoist or jackstands. Remove
wheel and tire assembly. (2) Remove caliper assembly, as described under
Brake Shoe Removal in this Group, (but do not dis-
connect brake line). Suspend caliper from wire hook
or loop to avoid strain on flexible hose. (3) Remove braking disc from the hub.
INSTALLING BRAKING DISC
(1) Slide braking disc on hub. Clean both sides of
braking disc with alcohol or suitable solvent. (2) Install caliper assembly, as described in Brake
Shoe Installation paragraph.
Fig. 2 Marking Braking Disc and Wheel Stud
Fig. 3 Checking Hub for Runout
Fig. 4 Index Braking Disc and Wheel Stud
5 - 54 BRAKES Ä

INSTALLING PARKING BRAKE SHOES
(1) Install rear parking brake shoe and holddown
clip (Fig. 6). (2) Install lower parking brake, shoe to shoe re-
turn spring (Fig. 7). (3) Pull forward parking brake shoe over anchor
block until properly located on adapter. (4) Install upper parking brake, shoe to shoe re-
turn spring (Fig. 8). (5) Install parking brake shoe adjuster assembly
with star wheel forward (Fig. 9). (6) Install front, parking brake shoe holddown clip
(Fig. 10). (7) Adjust parking brake shoes to a diameter to
171 mm (6.75 inch). (8) Install hub assembly on spindle.
(9) Install outer bearing, thrust washer and nut.
(10) Tighten wheel bearing adjusting nut to 27 to
34 N Im (240 to 300 in. lbs.) torque while rotating
hub. This seats the bearings. (11) Back off adjusting nut 1/4 turn (90É) then
tighten adjusting nut finger tight. (12) Position lock on nut with one pair of slots in
line with cotter pin hole. Install cotter pin. (13) Install grease cap.
(14) Install rear braking disc.
(15) Install rear, disc brake caliper on the adapter
(See Brake Shoe Removal).
Fig. 3 Removing Upper Spring
Fig. 4 Removing Shoe and Lower Spring
Fig. 5 Removing Rear Holddown Clip and Shoe
Fig. 6 Installing Rear Shoe and Hold-Down Clip
5 - 64 BRAKES Ä

(7) Unfasten brackets on steel heater water line at
dash panel and left frame rail. On Manual Transmis-
sion vehicles, unfasten clutch cable bracket at shock
tower and move aside. (8) Slide the power brake unit up and to the left
(mounting holes are slotted) on the dash panel, then
tilt inboard and up to remove.
CAUTION: Do not attempt to disassemble power
brake unit as this booster is serviced ONLY as a
complete assembly.
INSTALL (1) Position power brake booster onto dash panel.
(2) Install and tighten the 4 power brake booster to
dash panel mounting nuts (Fig. 5) to 29 N Im (250 in.
lbs.) torque. (3) Install steel heater water line and clutch cable
bracket, if so equipped. (4) Carefully position master cylinder on power
brake unit. (5) Install and tighten the 2 master cylinder to
power booster mounting nuts (Fig. 4) to 29 N Im (250
in. lbs.) torque. (6) Connect vacuum hose onto the check valve, lo-
cated on the power brake unit. (7) Using lubriplate, or equivalent, coat the bearing
surface of pedal pin (Fig. 5). (8) Connect power brake booster input rod to brake
pedal pin and install a NEW retainer clip. Use only a
new retainer clip DO NOT USE the old clip. (9) Check stop light operation.
WHEEL BEARINGS
FRONT WHEEL BEARINGS
Front wheel drive vehicles are equipped with per-
manently sealed front wheel bearings. There is no
periodic lubrication or maintenance recommended for
these units. However if during servicing of the brake
system, service to the front wheel bearing is required
refer to Group 2, Suspension in this service manual.
REAR WHEEL BEARINGS
NORMAL SERVICE
The lubricant in the rear wheel bearings should be
inspected whenever the hubs are removed to inspect
or service the brake system. Or at least every 30,000
miles (48,000 km). The bearings should be cleaned
and repacked with a High Temperature Multipurpose
E.P. Grease whenever the disc brake rotors are re-
surfaced.
INSPECTION
Check lubricant to see that it is adequate in quan-
tity and quality. If the grease is low in quantity, con-
tains dirt, appears dry or has been contaminated
with water, it will appear milky. The bearings then must be cleaned and repacked.
Do not add grease to
a wheel bearing that already has grease packed
in it. Relubricate completely. Mixing of different
types of greases in wheel bearings should be
avoided since it may result in excessive thinning
and leakage of the grease.
REMOVAL AND INSTALLATION
For the servicing, removal and installation of the
rear wheel bearings follow the procedure listed below. (1) Remove the rear tire and wheel assembly.
(2) On rear disc brake equipped vehicles remove the
caliper and rotor. Support the caliper out of the way.
Do not allow the caliper to hang by the hydraulic
hose. See disc brake section in this group for caliper
removal procedure. (3) Remove grease cap, cotter pin, nut lock, nut,
thrust washer and outer wheel bearing. (4) Carefully slide hub or drum from spindle. Do not
drag inner bearing or grease seal over stub axle
(thread, bearing, and oil seal may be damaged.) Using
an appropriate tool remove the grease seal and inner
bearing from the drum or hub. Discard grease
Fig. 5 Power Brake Booster Mounting
5 - 70 BRAKES Ä

(7) With the pressure bleeder turned on, open the
caliper bleed screw 3/4 to one full turn allowing brake
fluid to flow into the container. Leave bleed screw open
until a clear, bubble-free flow of brake fluid is coming
from the hose in the container. If the reservoir has been
drained or the hydraulic assembly removed from the
car before the bleeding operation. Slowly pump the
brake pedal one or two times while the bleed screw is
open and fluid is flowing. This will help purge any
trapped air from the hydraulic assembly. Tighten
bleeder screw to 10 N Im (7.5 ft. lbs.) torque.
(8) Step 7 above should be done at all wheel brakes,
following the order wheel by wheel as listed below. a) Left rear.
b) Right rear.
c) Left front.
d) Right front.
(9) After bleeding is completed at all four wheel
brakes. Remove pressure bleeding equipment and
adapter by closing pressure bleeder valve and slowly
unscrewing bleeder adapter from hydraulic assembly
reservoir. Failure to release pressure in the reser-
voir will cause spillage of brake fluid, and could
result in personal injury or damage to painted
surfaces. (10) Using a syringe or equivalent method, remove
excess fluid from the reservoir to bring the brake fluid
to the required fill level (Fig. 1). If brake fluid is below
the proper level add Mopar tbrake fluid or equivalent
conforming to DOT 3, requirements. (11) Install the reservoir caps and turn on the igni-
tion to allow the (ABS) pump to charge the accumula-
tor.
MANUAL BLEEDING
Brake lines can be bled, using the manual bleeding
method. Manual bleeding is a two person operation,
one to pump the brake pedal and the other to bleed
each wheel brake. The following procedure should be
used: De-pressurizing the hydraulic accumulator is done
by following the steps described below. (1) Verify that the ignition switch is in the off posi-
tion. (2) Fully de-pressurize the hydraulic accumulator by
pumping brake pedal a minimum of 40 times. Use the
procedure as described in De-Pressurizing Hydraulic
Accumulator listed earlier in this section.
WARNING: FAILURE TO DE-PRESSURIZE HYDRAU-
LIC ACCUMULATOR, PRIOR TO PERFORMING THIS
OPERATION, MAY RESULT IN PERSONAL INJURY
AND/OR DAMAGE TO PAINTED SURFACES.
(3) Connect a transparent hose to the bleed screw on
the wheel cylinder or brake caliper that is to be bled (Fig. 3). Submerge the free end of the hose in a
clear glass container, which is partially filled with
clean, fresh brake fluid.
(4) Slowly pump the brake pedal several times,
using full strokes of the pedal and allowing approxi-
mately five seconds between pedal strokes. After two or
three strokes, continue to hold pressure on the pedal,
keeping it at the bottom of its travel. (5) With pressure on the pedal, open the bleed screw
3/4 to 1 full turn. Leave bleed screw open until fluid no
longer flows from the hose. Tighten the bleed screw
and release the pedal. Be sure that the bleed screw
it tightened before brake pedal is released, or air
may be drawn back into hydraulic system. (6) Repeat Steps 3, 4 and 5 on each wheel brake,
until clear, bubble-free fluid flows from the hose. (7) Repeat the above sequence at each wheel brake,
in the following order: a) Left rear.
b) Right rear.
c) Left front.
d) Right front.
(8) Fill the hydraulic assembly to the proper fill level
(Fig. 1) using Mopar tor equivalent brake fluid meet-
ing DOT 3, requirements. (9) Install both reservoir caps on reservoir.
(10) Turn the ignition switch to the RUN position to
allow the Pump/Motor to turn on and recharge the
accumulator.
Fig. 3 Bleeding Brake System
Ä ANTI-LOCK 10 BRAKE SYSTEM 5 - 95