Having issues with your vehicle’s braking system? Noticing your brake pedal feels spongier than usual or you have to press down much harder to slow your vehicle? You may have a faulty brake booster that needs repair or replacement. Keep reading to learn more about brake boosters, symptoms of problems, whether you can repair it yourself, and when to call the pros.
Here’s a quick answer: You can attempt minor DIY repairs on a brake booster like replacing damaged hoses, testing the vacuum check valve, or replacing worn seals and gaskets. However, repairing or replacing the brake booster is generally best left to professional auto technicians since it’s a complex vacuum-assisted system that requires special tools, proper calibration and adjustments during service to avoid compromising brake safety through improper repairs or installation.
What is a Brake Booster?
A brake booster is a vacuum-assisted system that amplifies the pressure you apply to the brake pedal before it pushes brake fluid through the lines to slow and stop your vehicle. It makes braking easier and more effective.
Without a properly working brake booster, you’d have to press extremely hard on the brake pedal to stop the vehicle. Most cars have brake boosters, except for those with air brakes.
Here’s how it works:
When you press the brake pedal:
- A valve opens allowing engine vacuum into the brake booster unit
- The vacuum pressure helps push a diaphragm and rod against the master cylinder
- This adds force to the master cylinder piston, amplifying pressure
- More brake fluid is pushed through the lines applying the brakes
- When you release the pedal, the valve closes and vacuum is stored ready for next use.
Signs of a Faulty Brake Booster
Watch for these common indicators that your brake booster may be malfunctioning:
- The brake pedal feels very stiff and is difficult to press down
- The pedal seems to get stuck or doesn’t return quickly after braking
- Longer stopping distances – brakes feel less effective
- Brake pedal sinks to floor when engine running but firms up with engine off
- Brake pedal vibrates under heavy braking
- Unusual noises when braking, like hissing, groaning or whining
- Check engine light comes on due to engine vacuum leak
Don’t ignore these warning signs. Driving with brake problems is extremely hazardous. Have your vehicle inspected right away if you notice any of these issues.
Can You Repair a Brake Booster Yourself?
Repairing or replacing a brake booster is usually best left to professional technicians for a few reasons:
- Brake boosters have complicated vacuum-assisted mechanisms. Improper repairs could render it useless.
- All brake system components need proper calibration and adjustments during service for safety.
- Removing/reinstalling brake boosters requires disconnecting other components that could introduce leaks or air in lines if done incorrectly.
- Small errors or oversight in brake booster service could lead to brake failure and accidents.
That said, here are a few do-it-yourself fixes you could attempt:
- Check/replace vacuum hoses: Faulty, cracked or disconnected hoses can disrupt vacuum flow to the booster. Inspect hoses and replace damaged ones.
- Test/replace vacuum check valve: A bad check valve won’t hold vacuum for brake assist. Test or swap in new valve if faulty.
- Inspect/replace seals: Damaged or worn seals and gaskets allow vacuum leaks. Replace leaky seals if found.
Even these repairs require care to avoid creating bigger problems. Consider letting a professional handle it unless you have advanced DIY skills and tools.
When to Call a Professional
Most brake booster problems will require a trip to a professional mechanic’s shop. Here are some signs it’s time to get professional help:
- Brake pedal is extremely stiff and difficult to press
- Brakes feel completely ineffective making it hard to stop
- Brake pedal sinks to floor when engine runs indicating vacuum leak
- Brake light or Check Engine light comes on
- Odd brake noises, longer stopping distance, or vibration when braking
- Evidence of brake fluid leaks from booster unit
- Any symptoms get worse over time
Don’t delay repairs if you experience any of these issues, as driving with compromised brakes can lead to accidents. Call a trusted mechanic right away.
Brake Booster Replacement Cost
What can you expect to pay if your brake booster does need replacement? Prices can vary quite a bit based on:
- Vehicle make and model – parts cost between $100-$900+
- Whether just the booster needs replacement or other brake components
- Shop labor rates – expect 1-3 hours for installation
- Your location – rates vary across regions
On average, you can expect to pay $325 to $1250 for a brake booster replacement job, with most falling in the $500 to $800 range. Get quotes from a few shops before authorizing the repair.
Maintain Your Brakes
The best way to avoid an unexpected brake booster failure is proper maintenance. Follow your vehicle owner’s manual for recommended brake inspection intervals.
Signs it’s time for a brake inspection include:
- Squealing, grinding or other brake noises
- Vibration in steering wheel when braking
- Longer stopping distances
Replacing brake pads, rotors, and fluid on schedule will help prevent undue wear and damage to the brake booster and other components.
FAQs About Brake Booster Repair
Can you drive with a bad brake booster?
No, it is not safe to drive with a malfunctioning brake booster. Driving with compromised braking power risks accidents. Have the vehicle towed to a repair shop.
What if brake pedal is hard with engine on?
A brake pedal that’s stiff with the engine running indicates a loss of vacuum assist from the booster. Could be due to leaks, hose issues, bad check valve, or booster failure. Requires immediate repair.
Can low vacuum cause brake booster problems?
Yes, the brake booster relies on sufficient engine vacuum to operate. Weak vacuum from issues like intake leaks, head gasket failure, or valve problems can lead to booster malfunction.
How do mechanics test a brake booster?
Shops test brake boosters by pumping the pedal to eliminate vacuum, then checking that pedal firms up when engine is started. Measurements and tests verify proper boost assist, vacuum leaks, pedal ratio, and more.