Skip the auto shop - Our mechanics make house calls

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

asked by on

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.

A: Hi there. Most of the time this is due to a...

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.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: During ignition Taurus gagged for air, then backfired w/ smoke. Now engine light stays on & runs rough(timing off) 2005 Ford Taurus SE

Hello - the first task is to check for the problem codes which are setting the Check Engine light. This may be helpful in identifying the initial problem as well as the current problem(s). Usually, backfiring in the intake is...

Q: Hi Shaun! Can you help me determine whether my mechanic was being legit re: my AC issue?

Hello, thanks for writing in about your Kia Rondo. Unfortunately we can't confirm whether your mechanic is being legit because we don't know the complete conversation between you and the mechanic. Shops have their own prices for their services. You...

Q: Advice on how to find the exhaust manifold leak

The first thing to do is check it when the engine is cold. When it is cold the metal shrinks and if it is leaking, it will leak more. Also, since it's cold you can feel around with your hands....

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...