![I have a 88 legend coupe. After the a/c has been on for about 30 minutes, the brakes lose pressure and the pedal will go I have a 88 legend coupe. After the a/c has been on for about 30 minutes, the brakes lose pressure and the pedal will go](https://www.justanswer.com/uploads/acuramstr/2009-03-08_072542_SHOT0403.jpg)
I have a 88 legend coupe. After the a/c has been on for about 30 minutes, the brakes lose pressure and the pedal will go
Can a failed brake booster (or vacuum pump) cause a slowly sinking-to-floor brake pedal under sustained pedal pressure (with engine on only), and in detail, how? Assuming brakes otherwise work normally. -
![Defender 130 - Brakes well but pedal slowly sinks to the floor - Defender Forum (1983 - 2016) - LR4x4 - The Land Rover Forum Defender 130 - Brakes well but pedal slowly sinks to the floor - Defender Forum (1983 - 2016) - LR4x4 - The Land Rover Forum](https://content.invisioncic.com/r226025/monthly_2018_11/82_avatar_ad90b2f971d969379324d9e791c2f535_big.thumb.jpg.5dea0314576af45b2b7dd98a67bc4ccd.jpg)