1998 Oldsmobile LSS Brake Service (ONLINE REPAIR MANUALS)

Master Cylinder Overhaul

Except Aurora, Bonneville, Eighty-Eight, LeSabre, LSS, Park Avenue, Regency & Riviera

Disassemble

Refer to Figs. and when performing the following procedures.

• Remove master cylinder from vehicle as follows:
• Disconnect and plug hydraulic lines.
• Remove two master cylinder attaching nuts, then the master cylinder.
• Remove reservoir cover and diaphragm. Discard old brake fluid in reservoir.
• Inspect cover and diaphragm.
• Remove fluid level switch, if equipped.
• On models with compact master cylinder, remove proportioner valve assembly, Fig. .
• On all models, depress pri...

Brake System Bleed

Auto Bleed

Perform manual or pressure bleeding as outlined under " Manual Bleed" or "Pressure Bleed" before auto bleeding system

• Turn ignition switch to Off position.
• Raise and support vehicle. remove all tire and wheel assemblies.
• Inspect brake system for leaks and damage. Repair as necessary.
• Connect suitable programmed scan tool to Data Link Connector (DLC) located on lefthand side of instrument panel below steering column.
• Turn ignition switch to On position. Do not start engine.
• Establish scan tool communications by selecting ABS/TCS, Special Functions and Automate Bl...

Two basic types of power assist mechanisms are used: vacuum assist diaphragm assemblies, which use engine vacuum or, in some cases vacuum pressure developed by an external vacuum pump. The second type is a hydraulic pressure assist mechanism, which use pressure developed by an external pump (usually the power steering pump). Both systems act to increase the force exerted on the master cylinder piston by the operator. This in turn increases the hydraulic pressure delivered to the wheel cylinders, while decreasing driver effort necessary to obtain acceptable stopping performance.

V...

Replace

• Remove approximately ^2/3 of brake fluid from master cylinder.
• Raise and support front of vehicle, then remove wheel and tire assembly.
• Using suitable C-clamp, push piston back into caliper bore, Fig. .
• If caliper assembly is being removed for service, remove inlet fitting attaching bolt, copper washer, and inlet fitting from caliper housing. Plug opening in inlet fitting to prevent fluid loss and contamination. Do not crimp brake hose, as this may damage internal structure of hose. If only shoe and lining assemblies are to be replaced, do not disconnect brake line fitting fr...

AC-Delco Tandem Diaphragm Type

This unit utilizes a vacuum power chamber, consisting of a front and rear shell, housing divider, front and rear diaphragm, plate assemblies, hydraulic pushrod and a diaphragm return spring, Figs. and .

In normal operating mode, with service brakes in released position, the booster operates with vacuum on both sides of its diaphragms. When brakes are applied, air at atmospheric pressure is admitted to one side of each diaphragm to provide power assist. When the service brake is released, atmospheric air is shut off from one side of each diaphragm. The a...

• If any parts are of doubtful strength or quality due to heat discoloration, or are worn, replace them.
• Inspect wheel cylinder dust boots for signs of excessive wear or damage. If any leakage is apparent replace wheel cylinder.
• Clean dirt and/or rust from brake drum, backing plate and all other components. Do not use compressed air or dry brush to clean brake parts. Many brake parts contain asbestos fibers which, if inhaled, can cause serious injury. Clean brake parts with a water soaked rag or a suitable vacuum cleaner to minimize airborne dust.

Brake Drums

Any time the brake drums are r...