Hummer H1 Service Manual page 449

7-10 Brake System
1. Inspect dust boot for tears or deterioration (Figure 7-6).
2. Inspect rotor for heat cracks, spotting, discoloration,
pitting, or scoring. Resurface rotors if discolored, pitted,
or scored. It is not recommended that rotors be turned
when spotted or heat cracks.
3. Inspect brake pads for glazing, oil saturation, or wear. If
glazed, oil saturated, or if brake lining thickness is less
than 1/8 in. (3.2 mm), replace brake pads. Brake pads
should be replaced as an axle set (front or rear).
Installation
1. Check brake pad backing plate notches for burrs or excess
coating and ensure that the pad will fit the adapter slide
with enough clearance to afford stick-free movement.
2. Lubricate caliper guide pins, sleeves and adapter slides
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with Permatex Ultra Disc Brake Caliper Lube prior to
installation.
WARNING: Ensure brake pads are installed with lin-
ings facing rotor. Failure to do this will cause poor per-
formance, damage to equipment, and may result in
injury.
3. Position brake pads on adapter.
NOTE: When installing yoke and caliper, use a suitable tool to
compress the piston.
4. Apply a non-hardening thread-locking compound to
tapped holes of adapter. Using crowsfoot, secure yoke and
caliper to adapter with two washers and capscrews.
Tighten capscrews to 30-40 lb-ft (41-54 N•m).
LINING AND ROTOR BURNISHING
After you replace brake pads and/or refinish rotors, it is recom-
mended that the new braking surface be broken in, or "bur-
nished." To do this, make 20 stops, one every one to two miles
at 30 mph, using medium pedal effort. The amount of time it
takes to stop should be approximately five seconds. During this
procedure, use care to avoid overheating the brakes.
DUST BOOT
Figure 7-6: Caliper Assembly
4-1-00
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CALIPER
PISTON
FRONT SERVICE BRAKE CALIPER REPLACE-
MENT
NOTE: The following procedure applies to the front brake
system only. If removing left front caliper, halfshaft must be
removed.
Removal
1. Disconnect brake line from coupling (Figure 7-7).
2. Using crowfoot, remove two capscrews and washers
securing yoke and caliper to adapter.
NOTE: Note positioning of brake pad surfaces for installation.
3. Remove yoke, caliper, and two brake pads from adapter.
4. Slide yoke and caliper guide pins out from caliper.
Remove coupling and washer from caliper.
Cleaning and Inspection
NOTE: Clean all components, examine for wear or damage,
and replace if necessary.
1. Clean mating surfaces of caliper and adapter (Figure 7-7).
2. Inspect caliper and caliper piston for pitting, or damage
(Figure 7-6).
3. Inspect caliper guide pins and sleeves for wear.
4. Inspect dust boot and bushings for tears or deterioration.
5. Inspect yoke and caliper guide pins for corrosion. Perform
step 6 if corroded. If not, perform step 8 (Figure 7-7).
6. Remove caliper guide pins from yoke. Discard caliper
guide pins.
7. Inspect rotor for heat checks, discoloration, pitting, or
scoring. Check rotor thickness variation.
NOTE: Replace brake pads in sets only. Replace brake pads if
brake lining thickness is less than 1/8 in. (3.2 mm) and opera-
tion in wet and muddy conditions is expected.
8. Inspect brake pads for glazing, oil saturation, or wear. If
glazed, oil saturated, or if brake lining thickness is less
than 1/8 in. (3.2 mm), replace both pads and pads from
opposite caliper.
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