my brake pedal is stiff when my car is not running . when i start it the pedal, when pushed goes right to the floor
its your brake booster and like my b2600i, it probably has an internal leak. in other words replace both booster and master cylinder or check for vaccuum leaks or worn hoses and fluid leaks underneath the truck at all 4 corners. if there is none then depending on what year and how many miles and weather you've had the brakes serviced lately or ever. replace both. The cost is worth the insurance of being in an accident or not because your brakes failed.
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