Hummer H1 Service Manual page 469

7-30 Brake System
6. Install thrust screw as follows:
a. Align slot in thrust screw with centering pin.
b. Insert thrust screw in caliper and seat it on centering pin
and on ball bearings.
c. Compress thrust screw retaining ring with fingers and
install it in caliper bore below piston seal groove.
CAUTION: Do not use metal tools to install the retaining ring.
Metal tools will score or scratch the caliper bore.
d. Push assembly into bore as far as possible.
e. Seat retaining ring using unassembled caliper piston.
Lightly coat piston with DOT 3 brake fluid and insert it
in bore. Then push piston sharply downward two or
three times to seat retaining ring. Remove piston after
ring is seated.
7. Install new O-ring on centering pin plug. Then position
spacer on top of centering pin and install plug. Tighten
plug securely with hex wrench or socket.
8. Install new caliper piston seal. Start square cut seal into
groove at top of bore and work it into place with your
fingers. Lubricate seal and bore with fresh DOT 3 brake
fluid.
9. Assembly caliper piston as follows;
a. Install cone clutch in piston.
b. Lubricate bearing and race with DOT 3 brake fluid and
install them on cone clutch. The open side of bearing
goes toward race.
c. Install wave washer (either side up).
d. Install retaining ring with internal-type ring pliers. Flat
side of ring goes toward wave washer.
10. Install caliper piston as follows:
a. Install new dust boot on caliper piston.
b. Lubricate caliper piston with fresh brake fluid. Then in-
sert it through dust boot, into caliper bore, and onto
thrust screw.
c. Install parking brake lever on actuator shaft and rotate
lever to extend thrust screw.
d. Rotate piston onto thrust screw by hand, then with suit-
able size socket.
e. Turn parking lever to normal (non-applied) position and
complete piston installation as needed.
f. Seat piston dust boot in groove at top of caliper bore.
Use suitable size boot installer tool or flat punch.
11. Install new O-ring on piston retaining screw and install
screw. Tighten screw securely.
12. Install parking brake lever retainer and bolt. Apply 1-2
drops Loctite to bolt threads before installation.
13. Install and seat parking brake lever return spring in cable
housing slot.
14. Install bleed screw, if removed Apply anti-seize
compound to screw threads beforehand.
_____________________________________________________________
®