Q: poor brake performance when car's ac is on

asked by on April 30, 2016

When driving with ac system on. Usually in warm / hot weather. Braking performance is significantly poor. Pushing harder on the brake pedal doesn't seem to help. Wondering if this is common? How would I fix the issue?

My car has 230000 miles.
My car has an automatic transmission.

Hi there. Most of the time this is due to a loss of vacuum in the engine. A loss of vacuum drastically reduces the performance of the power brakes. I typically start by checking for any vacuum leaks in the engine. If there are none, then it may need a new vacuum booster. If you are going to have this repaired, consider YourMechanic, as a certified mechanic can come to your home or office to inspect your braking issue and make any repairs that are necessary.

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