Power Brake Booster

A power brake mainly uses hydraulic pressure with the help of a vacuum canister that allows air to enter the booster on one side while sealing off air on the other side. This creates an immense amount of pressure, causing the rod in the booster to push on the piston in the master cylinder responsible for your brakes. When you release the brakes, the vacuum reopens the valve and returns to its original position. In this process, you'll have stronger braking action.

If it's harder to press on your brakes, your power brake booster doesn't have as effective hydraulic power to assist you in braking. If this occurs, you must either inspect it yourself or hire a mechanic to diagnose the issue to prevent any further issues on the road, especially regarding your safety.

As mentioned, the most common sign of a failing power brake booster is a hard brake pedal. However, other signs may indicate your power brake booster may be in the process of failing instead of already being broken. If you find a longer stopping distance or hear a hissing noise when you brake, your power brake booster may need repair or replacement. In addition, your engine may stumble or stall, as your booster may be drawing air from other engine components. If this happens, your check engine light may also turn on.

We strongly advise against driving with a broken power brake booster, as you won't be able to brake efficiently. Stopping your vehicle with little effort is imperative to avoid an accident. You must replace the power brake booster immediately with the help of a mechanic.

Often, power brake boosters typically last just as long as the engine or the vehicle itself. However, you should inspect it regularly to spot disconnected hoses or broken valves in the booster that could affect your braking performance.

Your power brake booster may be failing for various reasons. For one, the entire booster may be unable to maintain enough vacuum pressure from the engine. However, the booster's vacuum hose or check valve can also fail, preventing the power brakes from building enough pressure. This occurs mainly from faulty parts or improper installation, as these parts are supposed to last more than 100,000 miles.

At Advance Auto, the cost of a power brake booster depends on whether you need one with or without the master cylinder. Without the master cylinder, we sell power brake boosters starting at $48, whereas brake boosters with the master cylinder can reach the end range around $615. The cost also depends on your vehicle's manufacturer's preference and the make and model of your vehicle. You may also want to consider the cost of labor to install the power brake booster if you can't install it yourself.

Typically, you'll need the help of a mechanic to replace an entire power brake booster. However, if it's simply a broken valve or hose, you can probably replace these parts yourself without the tools and experience of a professional mechanic. To diagnose the specific issue, spray dish soap mixed with water over your power brake booster while the engine runs. If you find bubbles or water getting sucked in a specific area, such as the joints, the check valve, the hose, or the seams, you've found the source of the issue. To determine if it's the vacuum supply, replace the vacuum hose with a gauge. If the gauge indicates pressure, the power brake booster itself is the issue. However, if there isn't pressure, there might be a broken hose or issues in the engine.

A vacuum booster uses engine vacuum to assist braking, while a hydraulic booster uses hydraulic pressure from the power steering pump. Each type has specific applications depending on vehicle design and performance requirements.