2000 Buick Lesabre Brake Service (ONLINE REPAIR MANUALS)

• If any components 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 components. Many brake components contain asbestos fibers which, if inhaled, can cause serious injury. Clean brake components with a water soaked rag or a suitable vacuum cleaner to minimize airborne dust.

Brake Drums

Any time t...

• Grease or any other foreign material must be kept off brake linings, caliper, surfaces of disc and external surfaces of hub during service procedures.
• Handling brake disc and caliper should be done in a way to avoid deformation of disc and nicking or scratching brake linings.
• If inspection reveals worn or damaged rubber piston seals, they should be replaced.
• During removal and installation of a wheel assembly, ensure not to interfere with or damage c...

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 required to obtain acceptable stopping performance.

Vac...

Master Cylinder Overhaul

Except Aurora, Bonneville, Corvette, CTS, Eighty-Eight, LeSabre, Park Avenue, Riviera & Vibe

Disassemble

Refer to Figs. and , when performing the following procedures.

• Disconnect and plug hydraulic lines.
• Remove mounting nuts and 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 equipped with compact master cylinder, remove proportioner valve, Fig. .
• On all models, depress primary piston and remove lock ring.
• Plug primary fluid outlet (outlet...

System Operation

The Anti-Lock Brake System (ABS) minimizes wheel lock-up during heavy braking. The ABS monitors each wheel's speed and controls brake fluid pressure to each wheel independently. A separate hydraulic line and solenoid valve for each wheel allows hydraulic pressure to be modulated, preventing wheel lock-up. The ABS can decrease, hold or increase hydraulic pressure.

The system continuously monitors all components, using several methods to determine faults and notify the driver of malfunctions. When the engine is started, the ABS electrical circuit is checked. As the veh...

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, then remove all tire and wheel assemblies.
• Inspect brake system for leaks and damage.
• Ensure battery is fully charged.
• 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...