Spongy Pedal

CAUSES
- Air is trapped in the hydraulic lines. The spongy feeling is a result of the air being compressed when the brakes are applied. Clean fresh brake fluid is non-compressible and will produce a firm brake pedal.
- Brake fluid is contaminated with water. During prolonged or severe braking, localized brake fluid temperatures can quickly exceed 220 degrees F. Any water in the brake fluid boils off into steam and creates a spongy pedal. As the brakes cool off the steam condenses back into water and the spongy feeling disappears.
- The rear drums are worn to thin. The spongy feeling is a result of the drums actually flexing into an oval as the brakes are applied.

WHAT TO CHECK FOR
- Verify that the master-cylinder reservoir is filled with clean fresh brake fluid.

NOTE: If at any time the master-cylinder reservoir has been emptied, the master-cylinder will need to be bled.

- Verify that the shoes/linings are properly adjusted, adjust if necessary.
- Bleed the brakes at all four wheels.

NOTE: Refill the master-cylinder after bleeding at each wheel.



- Remove the rear drums and measure the inside diameter of each. If either drum exceeds the maximum diameter specification, both must be replaced.

NOTE: Always replace both drums on an axle. Replacing only one drum will result in a different braking ability from side to side. This will produce a steering "pull" when the brakes are applied.

- If the brake pedal is still soft or spongy, flush the hydraulics and replace with clean fresh brake fluid, then bleed the brakes at all four wheels again.