Are you planning to service the hydraulic portion of your car’s brake system? If you service the brakes, like replacing the brake fluid or installing new parts, you should bleed the brakes afterward. A brake bleed is one of the most important jobs in car maintenance. Never skip brake bleeding to save time and cost in the short term. Otherwise, the brakes might develop issues down the road, making it more difficult to slow down or stop your vehicle.
Not bleeding the brakes can cause the following conditions:
It is the most noticeable issue caused by not bleeding the brakes. You have probably gotten used to the brake pedal resting at a specific height when you’re not engaging the brakes. When the pedal sits lower than usual, the abrupt gap can take you by surprise when your foot doesn’t immediately find it. You might also glance at the footwell and notice that the brake pedal has sunk down.
When the brake system doesn’t have enough hydraulic pressure, the brake pedal can end up sitting lower than it should. The most common reason is air bubbles trapped in the brake fluid. If you skip the brake bleed process, the air remains in the brake system, which reduces pressure and leads to issues like insufficient braking ability.
When you step on the pedal and encounter a spongy sensation, you might regret skipping the brake bleed.
A soft or spongy brake pedal gives way more readily than it should. You might need to press it harder before it applies the brakes. The delay between stepping on the pedal and the application of the brakes can cause traffic accidents.
When you step on the brake pedal, you trigger the braking process. While applying more force to the pedal increases the braking power, you don’t have to step very hard to engage the brakes in the first place.
If you don’t bleed the brakes, you might need to pump the brake pedal multiple times before it finally applies the brakes. This causes a potentially unsafe delay.
While failing to bleed the brakes will cause these issues, there are other reasons behind them. For example, brakes become spongy because of insufficient hydraulic pressure. While air bubbles are the most common cause for the drop in pressure, they aren’t the only possible one.
Brake fluid leaks in other parts can also decrease hydraulic pressure. If a brake line or the brake master cylinder leaks, the brake pedal might feel too soft.
The master cylinder can leak in two ways. Brake fluid can bypass the front seal near the pushrod and peel off the paint on the brake booster. Alternatively, an internal leak in the master cylinder compromises the seals inside the hydraulic part. Either way, you’re forced to pump the brake pedal.
Always perform thorough checks to determine what caused the brake pedal issue in the first place. Otherwise, you might replace a costly part, only to find that the pedal still looks low, feels spongy, or needs pumping.
Bleeding the brakes is a maintenance procedure that forces brake fluid through the hydraulic system. The influx of fluid expels air from the brake system, eliminating air bubbles that can block the passageways and reduce pressure.
There are several methods on how to bleed the brakes. While you should usually hire a professional to do the job, you can bleed brakes by yourself if you have the required tools and experience in DIY auto repair. Consult the appropriate repair manual or database for the recommended way to bleed your vehicle’s brakes. You also need a brake bleeder kit.
Air inside the braking system is not good news. Brake fluid is non-compressible, a property that lets it efficiently transmit hydraulic pressure easily. In contrast, air is compressible. If air bubbles are present in the brake fluid, they affect the lubricant’s compressibility.
The brake system needs hydraulic pressure to engage the mechanisms that decelerate the wheels and stop your vehicle. But if the brake fluid becomes more compressible because of air bubbles, it cannot transmit sufficient pressure.
There are several ways for air bubbles to appear in the brakes. Air can get inside the brake system when you open one of the hydraulic parts, such as a brake line or brake caliper. It’s the reason you should always bleed the brakes after servicing the hydraulic system.
Air can also enter the braking system through the brake lines. The lines are rubber, a flexible material with many tiny holes. When you release the brake pedal, air can enter through the tiny pores in the rubber hoses.
Additionally, a brake line’s connections might become loose enough to draw air into the brakes. Issues like excessive brake pressure can loosen one of the line’s ends, opening a gap that can admit air into the brake system.
If the brake fluid absorbs moisture, it can create air bubbles in the braking system. Moisture lowers the lubricant’s boiling point, the temperature at which a liquid or fluid boils. That’s because water has a lower boiling point than brake fluid.
Applying the brakes generates plenty of heat because of the friction between various brake parts. Usually, the brake fluid can handle the ensuing spike in temperatures. However, if the fluid has absorbed moisture, it can boil because of its reduced boiling point.
Boiling brake fluid creates air bubbles that travel through the hydraulic system. Eventually, they can reach the highest part of the brake system, which is usually the top of the master brake cylinder.
Bleed the brakes before flushing the old brake fluid. The interval between brake fluid flushes can vary between models. Some vehicles need new brake fluid every two years or 20,000 miles, while most professionals recommend every three or four years or 50,000 miles. Consult your owner’s manual for the manufacturer-recommended schedule.
If you opened the braking system to replace parts like the brake calipers, brake hose, and brake master cylinder, you should also perform a brake bleed. When you open the brakes, air can enter the hydraulic system and become trapped inside after you close it.
Are you having worn-out or damaged brake parts like the pads and rotors replaced? It’s a good time to perform a brake fluid inspection on your vehicle. Bleed the brakes and flush the dirty fluid as necessary.
Bleeding the brakes is worth the extra time, effort, and cost. It can save you from more serious problems with the brake system, especially if it involves your safety on the road.
Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.