GM Cavalier/Sunbird/Skyhawk/Firenza 1982-1994

Brake Master Cylinder



When adding fluid to the brake master cylinder, always use Delco Supreme fluid part no. 1052535 or equivalent DOT-3 brake fluid from a clean, sealed container.

Brake fluid damages paint. It also absorbs moisture from the air; never leave a container or the master cylinder uncovered longer than necessary. All parts in contact with the brake fluid (master cylinder, hoses, plunger assemblies, etc.) must be kept clean, since any contamination of the brake fluid will adversely affect braking performance.


See Figures 1, 2, 3 and 4

Once a month, the fluid level in the brake master cylinder should be checked.

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Fig. Fig. 1: For 1982-86 vehicles, the proper brake fluid level is approximately 1/4 in. below the lip of the master cylinder

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Fig. Fig. 2: The fluid level full mark is located on the inside of the reservoir on 1987-94 models

  1. Park the car on a level surface.
  3. Clean off the master cylinder cover before removal.
  5. On early models without a filler cap, the cover simply snaps onto the master cylinder body. Use your thumbs to press up on the two tabs on the side of the cover to unsnap it. Later model master cylinders have a fill cap.
  7. Remove the cover or cap, being careful not to drop or tear the rubber diaphragm underneath. Be careful also not to drip any brake fluid on painted surfaces; the stuff eats paint.

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Fig. Fig. 3: Clean off the master cylinder cover, then remove the cap

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Fig. Fig. 4: If necessary, add fluid from a fresh, sealed container

Brake fluid absorbs moisture from the air, which reduces effectiveness, and will corrode brake parts once in the system. Never leave the master cylinder or the brake fluid container uncovered for any longer than necessary.

  1. The fluid level should be about 1 / 4 in. (6mm) below the lip of the master cylinder well on early models or the full mark on the inside on later models.
  3. If fluid addition is necessary, use only extra heavy duty disc brake fluid meeting DOT 3 specifications. The fluid should be from a fresh, sealed container, because brake fluid deteriorates with age.
  5. Replace the cover or cap, making sure that the diaphragm is correctly seated.

If the brake fluid level is constantly low, the system should be checked for leaks. However, it is normal for the fluid level to fall gradually as the disc brake pads wear; expect the fluid level to drop not more than 1 / 8 in. for every 10,000 miles (16,000 km) of wear.