Solving Brake Problems
There are a lot of differing opinions on how to go about bleeding your brake system. No matter what, your brake system needs to be free of air in order to operate properly. If you’ve replaced a master cylinder, you can often just bleed the lines going into the master cylinder and be done.
However, sometimes you need to bleed all four wheels, and this is where the difference of opinion comes in. Some people like to bleed the brakes starting with the wheel that’s farthest from the master cylinder; in fact, this is how most people do it. After reading a Honda manual one day, I discovered that Honda actually wants you to start with the wheel that’s closest to the master cylinder. This might seem strange, but I tried it and it works pretty good.
Most brake systems are designed on what is called a split diagonal. This means that one front wheel and one back wheel are on the same master cylinder circuit. For example, the left front wheel is tied to the right rear wheel, and the right front wheel is tied to the left rear wheel. Manufacturers do this so you don’t lose just your front or rear brakes. If you did lose the front brakes, you would have a heck of a time stopping your vehicle. This is because the rear brakes only do about 20% of the braking on your vehicle.
To combat this issue, manufacturers came up with the split diagonal setup. This way, you should always have at least one front wheel and one rear wheel working. This is important when bleeding brakes, because you always bleed one front wheel, then go to the opposite side rear wheel and bleed there.
Conventional bleeding goes like this: right rear to left front, left rear to right front. I personally prefer left front to right rear and right front to left rear. But honestly, do what you feel is best. The main point is that you get all the air out of the system, how you do that is up to you.
You should periodically change the brake fluid in your vehicle; about every 30,000 miles is a good round number. The reason for this is because over time, brake fluid absorbs moisture and becomes acidic. This acid eats away at the internals of the brake system and can eventually cause a failure. In addition, as brake fluid ages, its boiling point gets lower. If your brake fluid boils, it can cause your brakes to fail. (I’ve never seen this happen on a street car; this would be a bigger concern on a race car or something like that.) Remember that brakes turn speed into heat. Your brake fluid has to deal with that heat. The newer the brake fluid, the better equipped it is to deal with that heat. To change your brake fluid is fairly simple. Just be sure to use the type of fluid your manufacturer calls for. It should be printed on the cap of the master cylinder or listed in the owners’ manual. Here’s a video on changing brake fluid.
At some point you might need to replace a brake line. Your local auto parts store might carry different lengths of brake line that already have fittings and flares. I suggest you go this route if you find you need to replace a brake line. If you do decide to do your own brake line flares, I strongly suggest you invest in the best flaring tool you can buy. Cheap flaring tools can wreck your day. A good flaring tool can save your day. I hope to do a video on this process as soon as I get my hands on one of those awesome flare tool sets.
Every once in a while, you run into a brake hose that gives you trouble. Sometimes they’re easy to spot. Sometimes you can see where the outer layer of a brake hose comes apart.
When you see this, replace the brake hose. Sometimes a brake hose fails and causes a caliper to hang up. You can find these by hitting the brake pedal several times and then opening the bleeder valve. If brake fluid comes out under pressure, it’s possible the brake hose has failed internally. What can happen inside the hose is that part of the inner hose collapses and it acts like a check valve. It will allow fluid to flow in one direction but not the other. When this happens, you can have an issue that seems like a faulty caliper, but it’s really a bad brake hose. So if you replace a caliper and you’re still having issues with that wheel hanging up, check the brake hose. By the way, one of the best upgrades you can do to your brake system is install steel-braided brake lines. You’ll be amazed at how good your brake pedal feels after you do this.
If you’ve done a bunch of work on your brake system and you’ve bled the wheels several times and you still can’t get a good brake pedal out of it, try this. Take the vehicle into a vacant parking lot and accelerate fast enough to lock up the wheels when you apply the brakes. Lock the brakes up several times and recheck your brake pedal. You might find that your brake pedal feels great after doing this. Just be sure that you’ve exhausted all other possibilities before doing this. It does work though. Here’s a video.