When you press on the brake pedal, it’s never good to get that sinking feeling. Instead, it should feel firm underfoot, providing the feedback that tells you all is well. If not, then something has definitely gone wrong.
How can you fix a sinking brake pedal?
Wouldn’t you know it? #savagescotty has the answer.
He says to:
- Look for leaks and repair any you find
- Replace the master cylinder
- Take it for a test drive
As with all auto repairs, even these three tips aren’t quite that simple. But with help from lifelong mechanic Scotty Kilmer, you can give it a go. If all else fails, you can always take your car into the shop to get the work done.
Start by Looking for Leaks
Scotty urges you to get down on the ground and look for leaks whenever your brake pedal feels far too soft. He states that your problem likely comes down to an internal or external leak.
So, you must check out the calipers, shoes, and lines for signs of a problem. Don’t forget to check all four wheels and all along the brake lines under the car. If anything looks wet, then you likely have an external leak and need to replace broken parts.
Replace the Master Cylinder
If there’s no noticeable leaks, then you can turn your attention to the master cylinder. This important part not only holds the brake fluid, but also pushes it through the lines when you press down the pedal.
If anything has gone awry inside, it won’t create enough pressure, causing your pedal to sink. Here’s how to fix it.
1. Buy a New Master Cylinder
Before you start taking anything apart, use a different car to drive down to the auto parts store. Pick up a replacement master cylinder and a bottle of brake fluid.
Kilmer points out that it’s always best to buy a new master cylinder instead of a refurbished one. The rebuilt ones are not likely to last as long and could even fail to work right from the start.
2. Loosen up the Lines
The installation process starts with the removal of the old master cylinder. Start by disconnecting the brake lines going to it using hand tools.
On the car in the video, Scotty uses a 10mm flare nut wrench to loosen the lines. Then, he uses his thumb and finger to unscrew the lines the rest of the way.
3. Remove the Bolts
Next, you’ll need to take off the two nuts at the rear bracket of the master cylinder. This time, Kilmer uses a 10mm socket to unscrew both nuts.
After setting the nuts to the side, just give the master cylinder a wiggle and pull it right off. Then, empty the old fluid into a container for proper disposal and throw the old part away.
4. Install the New Master Cylinder
Grab your new master cylinder and fit its bracket over the two studs. You’ll need to use the two nuts you removed in the prior step to secure it in place. Use your fingers to thread the nuts onto the studs, then tighten them down with hand tools.
5. Bleed the Air Out
Fill the reservoir with new brake fluid. Don’t reuse your old fluid. After that, attach the brake lines to the two ports on the master cylinder, but keep them loose for now.
Have a friend press the brake pedal to the floor. If you don’t have a helper nearby, wedge a screwdriver between your seat and the pedal instead. With the pedal pressed down all the way, tighten the lines on the master cylinder, and then release the brake pedal.
Repeat this process about five times to get all the air out of the system. Once that’s complete, go check that your brake pedal feels firm underfoot. If not, you may need to keep bleeding the brakes until it feels right.
Time to Enjoy Your Brakes Feeling Like New Once Again
After you bleed all the air out of the lines, all that’s left to do is go on a test drive. If your pedal still doesn’t feel 100%, visit your preferred auto shop and let a mechanic take a look. Just remember to pull your Vehicle History before you go, so you have all the info you need on hand.
