When you try to slow down and an unfamiliar squishy sensation results, it points to one thing: air in the brakes. Trapped air can affect brake performance; if the problem worsens, the brakes could fail. Fortunately, the problem can sometimes be resolved by bleeding the brakes. Here’s five tips for bleeding brakes and staying safe while doing it. Keep in mind that some modern brake systems require special diagnostic tools to be serviced correctly, so it may be best to let the experts at your local NAPA AutoCare can handle it for you.
1. Always Place Your Vehicle On Jack Stands
At some point, you’ll remove each wheel to reach the brake bleeder screw. Any time you plan on being underneath a car, regardless of how short a time you think it will be, always use jack stands. More than likely you will be reaching in, around, and under the car to access the brake bleeder screws. There are zero excuses for not using jacks stands when working under a car. Speaking of safety, put on a pair of safety glasses as well. Between splashing brake fluid and nasty crud from under the car, your eyes will thank you.
2. Go The Distance
Begin with the brakes located the furthest away from the master cylinder. Typically, this would represent the rear brake on the passenger side. Move to next furthest away and so on. Always wear gloves and eye protection, as brake fluid is toxic.
3. Be Kind To Your Bleeder Screws
Use a bleeder or box end wrench to loosen the bleeder, not pliers. The last thing you want is to strip the hex head on the bleeder screw. If the screw is very tight, apply WD-40 or another lubricant to loosen it. While the bleeder may be tight, be wary of applying too much torque while loosening it. It is better to soak the bleeder screw with lubricant and let it sit, than to risk breaking off the bleeder screw.
4. Check the Master Cylinder
Not to be neglected in this process is the master cylinder — a hydraulic pump that sends pressurized brake fluid through the brake lines to the calipers or wheel cylinders. Check the brake fluid level and use a funnel to add fresh fluid if it drops below the minimum line. Do not overfill. Clean the inside of the cap to remove dirt or debris before reattaching it. Refer to your owner’s manual to find the correct brake fluid type for your car.
5. Check Brake Feel
Once each of the brakes has been bled and the master cylinder replenished, check the pedal pressure to ensure that the squishy feeling is gone. If the pedal feels firm to the touch, then you’re done. Otherwise, repeat the brake bleeding process until all air is removed. When you’re satisfied with your work, reattach the wheels and remove the car from the jack stands. You can recycle old brake fluid in the same way as motor oil.
In addition to regularly checking your brake pads and discs for wear, examine the brake lines. Brake lines are prone to corrosion, cracking and stiffening, which can lead to leaks and damage to key components of your car.
Check out all the brake system products available on NAPA Online or trust one of our 16,000 NAPA AutoCare locations for routine maintenance and repairs. For more tips on bleeding brakes, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.
Photo courtesy of Flickr.
Bleed your Trailer Brake System
After replacing the backer and tightening the brake line to the wheel cylinder, follow these steps to bleed your trailer brake system.
Remove the master cylinder cap and fill the reservoir to three-quarters full with brake fluid.
Note: To manually bleed the system, you will need two people to make the job easier.
With a Demco or Dexter brake actuator, pulling the breakaway cable lever will actuate your brakes. While one person is slowly pulling the breakaway lever, the other should loosen the bleeder screw on the back of the wheel cylinder, then tighten the bleeder screw back before pulling the breakaway lever back to its normal position (You will need to repeat this procedure several times until you have fluid coming out of the bleeder screw with no air bubbles visible in the fluid). After you have a steady flow of fluid coming out of the bleeder, as the breakaway lever is pulled forward, you can then switch to the next wheel and repeat this method until all brakes have been bled. As you move around the trailer, you should continue to check the fluid level in the reservoir as the fluid level will drop as you pump fluid back to the brakes.Note: Brake fluid will damage any painted surface. If you happen to get some fluid on your trailer’s painted areas, be sure to wipe the fluid off immediately.
- If your brakes feel spongy and faint or are not working properly, there may still be air in the brake system and the system will have to be re-bleed.