Air is essential for life. That’s a correct statement. You need air to breathe. No argument there. But air isn’t good everywhere, all the time. Take your brake system, for example. Air in your car’s brake system can have disastrous consequences – not only for brake parts like the pads, rotors and master cylinder, but for safety reasons, too.
If you’re interested in fixing your brakes, whether it’s simply changing the brake pads or a more in-depth project like rotor and caliper replacement, you should know 2 things:
1. Bleeding the brakes is an important – and often ignored – part of the process.
2. How to bleed your brakes.
Get those two items in order, and your braking will remain responsive and robust for miles to come.
When In Doubt, Bleed Your Brakes
Why is bleeding your brakes so important? And when should you do it? Generally speaking, anytime the brake fluid reservoir is opened. Whenever the cap comes off, a tiny bit of air enters into the hydraulic fluid system. Just a little bit of air can cause big problems.
Your car’s brake system depends on a strong, ready flow of brake fluid – and brake fluid only. The master cylinder takes a signal (every time you press the brake pedal) to compress each caliper’s inner piston to squeeze each rotor with the brake pads. A similar process takes place with drum brakes, although in a slightly different manner.
Regardless, your car’s brakes are only as good as the hydraulic fluid moving back and forth from the master cylinder to the calipers, drum brakes and so forth. And to ensure the best possible performance, the only thing in your brakes lines should be brake fluid, period. No air, no oxygen bubbles, nothing else. Whenever there’s something else besides brake fluid inside, problems can literally bubble to the surface. That’s why it’s crucial to bleed your brakes every time you work on your brakes.
One Man’s Brake Blunder from not Bleeding
The author of this article, in fact, knows all too well about the importance of bleeding brakes. Yours truly once changed the brakes on a 1989 Ford Festiva, back during the early 1990s, when Pearl Jam was popular and George Bush (the "first" Bush) was in the White House.
Mind you, the Ford Festiva was never known for its safety characteristics. With a flimsy body, suspect handling and barely enough horsepower to safely enter a highway, the Festiva wasn’t exactly a hot commodity. But a full gas tank back then cost less than $10, and the car’s 12-inch donuts meant a paltry $99 bill for four brand-new tires – mounted, balanced, out the door. Always an affordable silver lining.
Back to the brake job – I replaced the brake pads and rotors on the front axle. That's four pads and two rotors if you're counting at home. Nothing spectacular; just run of the mill, routine maintenance. Once the new parts were in place, I slowly took the Festiva for a half-mile spin on my quiet residential street. Immediately, I knew something was wrong. The brakes had that sloshy, unresponsive feel. In fact, approaching the first stop sign, I had to repeatedly pump the brake pedal multiple times to the floor to stop the car, which had drifted into the intersection. Thankfully, no other cars were around.
Carefully driving the car back home the half-mile, I tried to figure out what was wrong. And once I asked my dad (who happened to be at work during my brake job adventure), I found out immediately: “Well, did you bleed the brakes?” Not only did I not know how to bleed the brakes, I didn’t even know what the term meant. Leave it to dad to fill in the knowledge gap. After a quick brake bleed, the Festiva was back on the road, brakes fully functional.
How To Bleed Your Brakes
The process of bleeding brakes purges all air out of the brake fluid system. It’s a pretty simple process. You only need a few items, and just 5 minutes or so. And since you’ve already spent the better part of an hour or two working on your brakes, what’s another 5 minutes?
Checklist
Before bleeding your brakes, collect the following things:
- A clear glass jar
- A small wrench to turn the brake bleeder nozzle
- Some flexible hose, at least a foot long
- Brake fluid
- A buddy
Step-by-step process
1. Locate the brake bleeder nozzle / screw. It’s usually located on the inside of the wheel, on the side of the caliper.
2. With the proper tool, loosen the nozzle. If it’s stuck, try some WD-40 to free up the nozzle. Be careful not to break off the nozzle bleeder – repairs for this part are expensive!
3. Take the flexible hose and place one end over the bleeder nozzle. Place the other end in the glass jar, and put enough brake fluid in the jar to immerse the end of the hose.
4. Make sure you have some cardboard or newspaper underneath to catch any extra liquid.
5. Have your buddy press the brake pedal a few times.
6. With the brake pedal all the way down, slightly open the bleeder nozzle.
7. Take note of any air bubbles flowing into the jar with brake fluid.
8. Before your buddy releases the brake pedal, tighten the bleeder screw. Failure to tighten the screw will result in air back in the brake fluid, and that’s what you’re trying to avoid.
9. Repeat steps 5-8 until no air is noticeable in the brake lines.
10. Add brake fluid to the brake reservoir as required.
11. Repeat as necessary for each wheel.
12. When finished, take your car for a test drive. Pay attention to anything abnormal. If required, repeat bleeding process to purge any extra air out of the system.
A less popular method is the solo route,but we recommend bleeding the brakes with a friend. The job will be done quicker, you’ll have someone to pass the time with, and you can also get a different perspective, either down by the brakes or behind the wheel.
We hope this how to article – and a brief interlude into a past brake job blunder – helps you avoid brake troubles down the road. The next time you take on a brake replacement, remember to bleed the brakes. Whether you go it alone or use the buddy system, you’ll give your car the best possible braking performance, no matter what year, make & model you drive.
To start your next brake replacement today, get started at BuyAutoParts.com. If you have any questions about our line of brake parts, give our auto parts consultants a call at (888) 907-7225, or visit ourcontact page to chat with a BuyAutoParts.com representative.
