Unusual Brake Problem
I have an ’82 Chevy c10 pickup with a 6.2 L Diesel with probably 300+ kmiles on it. It has a power brake booster driven by the power steering pump. My wife was driving it the other day and said that when she applied the brakes they felt soft, almost as if there were air in the lines. She also noticed that when this happened the red “Brake light” on the instrument panel “flashed on” momentarily. Once she pumped the brakes they felt fine. She said this happened twice, both times after driving on the freeway for about 15 minutes without using the brakes. When the brakes were used over short time intervals they felt normal.
I did a quick check and the fluid levels were tiptop and there is no leakage of any fluids anywhere. Any ideas on what might be going on?
i would bleed the brakes and make sure theres no air in the lines. If it continues after you bleed them, i would test the master cylinder.