1998 Oldsmobile Regency Brake Service (ONLINE REPAIR MANUALS)

When troubleshooting the hydraulic brake system, perform the following checks and inspections as outlined below. If problem still exists within system, refer to Fig. first, then to Figs. and as necessary.

Master Cylinder Internal Fluid Leakage Check

Start engine and depress the brake pedal. If the pedal gradually falls under constant pressure, the hydraulic system may be leaking. Raise the vehicle on a lift and check all tubing lines and backing plates for signs of leakage. It may be necessary to ...

AC-Delco Tandem Diaphragm Type

This brake booster is not serviceable and should be replaced as an assembly.

AC-Delco Single Diaphragm Type

This brake booster is not serviceable and should be replaced as an assembly.

Toyota/GM Single Diaphragm Type

Overhaul

Disassemble

• Attach holding fixture tool No. J-22805-01, or equivalent, to front of booster, then mount fixture in vise. Mounting holes of holding fixture may have to be elongated toward inside in order to accommodate booster master cylinder studs.
• Scribe matching marks between front and rear booster shells to aid assembling.
• R...

Brake Roughness

The most common cause of brake chatter on disc brakes is a variation in thickness of the disc. If roughness or vibration is encountered during highway operation or if pedal pulsation is experienced at low speeds, the disc may have excessive thickness variation. To check for this condition, measure the disc at 12 points with a micrometer at a radius approximately one inch from edge of disc. If thickness measurements vary by more than .0005 inch,...

• 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...

When working on or around brake assemblies, care must be taken to prevent breathing asbestos dust, as many manufacturers incorporate asbestos fibers in the production of brake linings. During routine service operations the amount of asbestos dust from brake lining wear is at a low level due to a chemical breakdown during use, and a few precautions will minimize exposure.

• Do not sand or grind brake linings unless suitable local exhaust ventilation equipment is used to prevent excessive asbestos exposure.
• Wear a suitable respirator approved for asbestos dust use during all repair proced...

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