Pontiac Fiero 1988 Service Manual page 239

5A3-2 COMPOSITE MASTER CYLINDER
GENERAL DESCRIPTION
This master cylinder is a composite design
(plastic reservoir and aluminum bore) incorporating a
conventional front to rear brake system split. The
primary piston provides the fluid pressure to the front
brakes, while the secondary piston provides the fluid
pressure to the rear brakes. If pressure is lost from
either system, the remaining system will function to
stop the vehicle.
A quick take-up feature is incorporated which
provides a large volume of fluid to the wheel brakes at
low pressure with initial brake apply. The low pressure
fluid quickly provides the displacement requirements
created by the seal retraction of the pistons into the
front calipers.
Important
Replace all components included in repair kits
used to service this master cylinder.
Lubricate rubber parts with clean brake fluid to
ease assembly.
Do not use lubricated shop air on brake parts as
damage to rubber components may result.
If any hydraulic component is removed or
disconnected, it may be necessary to bleed all or
part of the brake system.
The torque values specified are for dry,
unlubricated fasteners.
• Perform service operations on a clean bench free
from all mineral oil materials.
ON-CAR SERVICE
MASTER CYLINDER A S S E M B L Y
[<h+j Remove or Disconnect (Figure 5A3-2)
1. Tube nuts (14) and hydraulic lines.
• Plug open lines to prevent fluid loss and
contamination.
2. Two attaching nuts (15).
3. Master cylinder (13).
• See NOTICE on page 5-1.
Install or Connect (Figure 5A3-2)
1. Master cylinder (13) with attaching nuts (15) to
27N-m(201b-ft).
2. Hydraulic lines and tube nuts (14) to 23 N-m (17
lb-ft).
3. Fill master cylinder to proper level with clean
brake fluid.
• Bleed hydraulic system.
• Recheck fluid level.
13. M A S T E R C Y L I N D E R
A S S E M B L Y
14. T U B E N U T
15. N U T
HM0002-5A3-BG
1.
Figure 5A3-2 Removing Master Cylinder Assembly
UNIT REPAIR
MASTER CYLINDER OVERHAUL ' '
1 * 1 * 1 Disassemble (Figure 5A3-1)
Important
Reservoir cover and diaphragm can be
inspected and/or serviced without
removing the master cylinder from the
vehicle.
Master cylinder (13) completely from vehicle as
previously described.
Reservoir cover (1) and diaphragm (2).
• Wipe reservoir cover clean before removing.
• Empty fluid from reservoir (only if master
cylinder is to be completely removed and
overhauled).
Inspect
Reservoir cover (1) and diaphragm (2) for:
• Cuts
• Cracks
• Nicks
• Deformation
Replace damaged parts.
Retainer (5) while depressing primary piston
assembly (6).
• Take care not to damage the piston, bore, or
retainer groove.
Apply low pressure dry compressed air into
outlet port at blind end of bore (other outlet port
plugged) to remove:
• Primary piston assembly (6).
m Secondary piston (10).
• Spring (11).
• Spring retainer (8).
From secondary piston (10):
• Seals (7 and 9).
• Spring retainer (8).
4.