How to Bleed Brakes

Here's a tool that you have gotta know about. Here's what happens, you go to do a brake job on a vehicle and when you get to the end of that brake job, you can do everything by yourself except for the bleeding part. Because what happens is, the typical scenario, you top off the master cylinder, somebody sits in the cab, pumps on the brake pedal, somebody else is under the vehicle, opening and closing the bleeder valves. So here's a solution to that problem. Pretty low tech but very, very handy.

What we need to do is create some kind of a vacuum at the bleeder that would let us just draw fluid through the system instead of pushing it through the system using the brake pedal. So here's one solution to that. What I can do is hook this using a hose up to the bleeder. As I pump this, manually here, I'm creating a vacuum. As I create a vacuum, that's also then created inside here.

That pulls fluid in. The idea is exactly the same. I can see into this cylinder. So as I'm watching in here, I'm watching for the part where I start to get fluid only, no air bubbles. That's gonna tell me I'm okay.

So this is gonna do it for ya, this is a manual system. This one's a little bit higher tech. This one requires compressed air. It's got a couple aspects to it. I hook it up to air.

As I squeeze this, my high pressure air shoots across the top of this chamber. That creates a vacuum which is then gonna draw through this line, which is like the other one, connected up to my bleeder valve. Now the purpose of this thing is that we wanna make sure we don't run the system dry. So I can take this, fill it full of brake fluid, various adapters available for it, invert it on the reservoir, turn it open. This is gonna make sure that my fluid stays ahead of the fluid that's in the reservoir so that I don't accidentally drain the whole system dry.

It's great to know about this stuff for a couple reasons. One, of course, if you do the brake job, then you know you gotta get in there and bleed the system. Now additionally, let's say you pick up a used vehicle you don't know anything about, the life of the brake fluid that's in there. It's a good idea to swap it off for new. Brake fluid is capable of just grabbing ambient humidity out of the air and pulling that moisture right into the brake system.

So if you don't know what you've got, your best bet is to start from scratch. These tools are gonna make it a lot easier to do 'cause instead of shagging down a buddy, finding him, having him pump that brake pedal for ya, you're gonna be able to do everything yourself. This is a great set of tools that you gotta know about.