Posted by Karl Koenig on January 28, 1999 at 23:58:59:
In Reply to: e12 Brake Booster posted by Wietse Wullink on January 28, 1999 at 23:02:16:
: OK e12ers, here is another one.
[snip}
: Here is the operating conditions;
: Engine idles great, but after the first 30% of the brake pedal travel I can hear an audiable "hiss" inside the car and the idle changes (gets rough, like there is a vacuum leak).
I think this is the clue that the brake booster is dying.
: The brakes also do not have that "launch you into the dash" feeling and I can not lock up any of my wheels with full pedal pressure. I used to have brakes like this.
: First 30% of the travel, no issue and great power assist.
: Is this hiss normal? [snip]
Both the hiss and the action of your brakes are not normal. I do not know a way to test a brake booster that only leaks when the pedal is depressed.
Wish you luck
karl