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A/C & braking - vacuum relationship?

1994 GTi 2.0. 100k miles. When the A/C is turned on, the car requires more "foot effort" to brake. I can be pressing he brake pedal and if I turn the A/C off, the pedal goes a little bit inwards, because of the lower effort required. The A/C has recieved maintenance. I thnik it must be something vacuum related. The A/C compressor does have a lot of internal resistence, the car gets noticeably slower, with no low end torque at all (far below normal).

Are the a/c and the vacuum system related? Maybe because of the increased power the engine needs no turn the a/c compressor?

thanks

Bob

Reply to
ghinghis
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Maybe a leak in vacuum controls for the A/C.

Reply to
Joseph Meehan

YES!

Reply to
Woodchuck

Reply to
Woodchuck

That's what I was thinking of.

Reply to
Joseph Meehan

When you turn on the A/C, the ECU will open up a valve to allow more air / fuel to the engine. This will reduce the vacuum in the manifold (increase absolute pressure) and thus you will get less boost from the brake booster. It is normal for this to be noticeable, if it actually reduces brake performance you might have a vacuum leak in or around the booster.

Reply to
Randolph

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