I drove my wife's 1993 Integra LS on the weekend. First time I had eny extensive driving in it. Brakes felt a little soft, but nothing seemed too bad.

While coming through California's central valley (where we needed some air-conditioning) I noticed the brakes were a little softer. Little did I realize (until after we got off the freeway and had to deal with some traffic lights) that while sitting with my foot on the brake it was sinking to the floor!

I mentioned this to her, she said "Oh it always does that when the air conditioning is on, it's been like that since I bought it". I freaked. For one thing, I noticed that braking was lame everywhere.

I am going to get her a new master cylinder and install it one night this week. No doubt that is the problem.

What I don't get is how come this is really only apparent when the air conditioning is running. Anyone know why?

Thanks,
madkiwi

 

When my MC went, it seemed worse when it was really hot. Running the AC makes it hotter under the hood. But it seems like there'd be more to it than that. Like on a cooler rainy day when you run the AC to clear fog from the windshield? Or like my car would do it on a really hot day even without the AC...