Bendix Master Cylinder - GMC 1989 Light Duty Truck Repair Manual

5-6 BRAKES
Figure 10—Composite Master Cylinder Components
5. Primary piston assembly (30).
6. Snap ring (31).
• The primary piston must be compressed to
install the snap ring.
7. Diaphragm (23) into the cover (22).
8. Cover (22).
Figure 11—Removing the Reservoir
Cover
Diaphragm
R e se rvo ir
G rom m et
Q uick Take-Up
Valve
Spring
Spring R etainer
Primary Seal
Secondary Piston
Secondary Seal
Snap Ring
Primary Piston
A ssem bly
Body
F-00770
9. Tube seats (if removed).
• Seat the tube seats with a spare brake tube
nut (figure 18).

BENDIX MASTER CYLINDER

The Bendix Master Cylinder has identifying information
stamped into the front surface of the body. The first digit
indicates the plant where it was built. The second digit
indicates the year it was built (a 5 means 1985 or a 6
means 1986). The last digits indicate the day it was built
(271 means the 271st day of the production year).
NOTICE: Do not hone the master cylinder bore.
When the brake master cylinder is overhauled,
it is recommended that the cylinder body be
replaced rather than "cleaned up" by honing
the bore. The master cylinder has a hard, highly
polished " bearingized" surface, which is
produced by diamond boring followed by ball or
roller burnishing under heavy pressure. Honing
will destroy this surface which will cause rapid
wear of rubber cups.
NOTICE: Do not use kerosene, gasoline, or any
other unapproved solvents for cleaning or
flushing master cylinder and components. The
use of these as solvents or any other with a
trace of mineral oil will damage rubber parts.
Figure 13—Installing the Reservoir