How to Flush Brake Fluid System 2000-06 Chevy Silverado 2500 Diesel

Hi, I’m Mike from 1A Auto. We’ve been selling auto parts for over 30 years!

So our vehicle has poor braking performance even though the brakes are new, so we went and checked the brake fluid reservoir, and it turns out, when you open it up and look inside, it's real dirty and gross. So this brake fluid is old, and it needs to be changed. Because what happens is brake fluid is hygroscopic, and it will absorb water over time, and with that, it pulls in dirt and stuff because there's just moisture in the air, and eventually, just follow your recommendations in your owner's manual.

There's usually a time span when this stuff needs to be flushed, so we're going to flush it on this vehicle, but just to give you an idea, this is a turkey baster. Don't go grabbing one from your kitchen. Get a new one just for this cause once you use it for brake fluid, it can't be used for anything else.

If we look over here in our bottle, this is brand new brake fluid. It's nice and clean and clear and kind of a golden yellow. Let me take some of this out of the reservoir. We're actually going to use this turkey baster to empty this reservoir so we don't have to flush dirty fluid through the system, but I'll take some out so you can see it, and it's not really that clear or bright yellow. It's kind of greenish, dark and gross, so we're going to suck it all out, and then flush it and put fresh stuff in.

So brake fluid is toxic, and it damages paint, so you're going to wear some gloves and also put it in a container and dispose of it properly. So we're going to just take out the old stuff and just repeat this until you get as much out of the reservoir as you can. And here's as much as we can get out. The rest will have to get flushed through. You can see that stuff is really, really dirty. It's not clean and clear, and instead of flushing this all through the system, we took it out of the reservoir first.

This is a liter bottle, so it's quite a bit of fluid. Here's an even clearer example. This is the old, dirty fluid that's got dirt—brake fluid is hygroscopic, so water has mixed with this, and you basically pieces of rust and stuff from inside the brake system. This is brand new fluid. You can see it's nice and clear and clean. It doesn't have water in it, so what will happen when this gets dirty like this—it's got a lot of water in it, and it reduces your braking performance because the water can actually boil when it gets hot.

In the cold weather, some of this brake fluid can actually freeze. You can get little ice particles in it. It'll reduce your braking performance, so you really want to follow your vehicle's recommended intervals for changing the brake fluid, and like on this vehicle, we're going to flush it out. Now that we've disposed of this fluid properly, you can see that it's collected on the bottom, some of these dirt particles. That is floating in the fluid. It can clog up your braking system.

I'm going to clean up the spilled brake fluid using the turkey baster to remove the old stuff. I'll put a funnel in. Take some fresh fluid and top it off before we got to flush the system. Right on the cap. This vehicle recommends dot three, but always check your reservoir cap or your owner's manual for the proper type of brake fluid.

To flush your brake fluid, you're going to need to remove at least one of your wheels at a time. It's easiest if you can remove all of your wheels at the same time, so you may need to have your car jacked up on four jack stands. We're using a two-post lift. You could do it one wheel at a time. If you can get to the bleeder screw without putting the wheels up and underneath the vehicle, you could do it that way too, but you're going to want to start with the passenger side rear. That's the further most brake from the reservoir, and then we're going to move to this wheel, which is the second further most.

This is the driver's side rear. Then you'll do the passenger side first, and then finally the driver side front because that is the closest to the reservoir. The lines that run to the driver's side rear to the passenger side rear are the longest, so you'll want to flush those first. Some three-sixteenths fuel hose with this bottle, and I drilled a hole that fits it through the cap and also a little vent hole in it. Put a little zip tie on there so it can't pull back through. So I'm going to screw this back in, and what's going to happen when I loosen the bleed screw, this hose will be over the top of it, and the fluid will flow down into the bottle, and it'll catch the fluid so it doesn't go all over the floor. Put that aside for now.

The bleed through looks a little bit rusty and we're missing the cap. Let's say some rust penetrant on it. Take our wire brush and knock as much rust off of it as I can. Take some brake parts cleaner to clean around it. I'm going to crack the bleeder screw free using the boxed in of a 10mm wrench, so it's moving, which is good. And there's already fluid coming out, which is also good, so I'm going to close it. I'm going to force the end of the hose. It's going to be real tight, which is good because we don't want it to leak.

That's going to go right over the bleeder screw. Just like that. Now I know the bleeder screw will move, so I can open it. There is goes. So now I'm going to go inside the vehicle and just gently pump the brake pedal. I'm going to do this about three times. So I'm going to close this, and then I'll pump it up again and open it. Ideally, you'd use a clear hose. Sometimes it's difficult to find clear hose. Tighten the bleeder. Then I'll pump it up and open it up again. I'm just going to repeat this three or four times to try and flush out all that fluid.

With the bleeder closed, I'm actually going to empty this bottle, and then I'll reconnect it, and I'll keep pumping it until this bottle fills with clear fluid. Just make sure the master cylinder remains topped off. Continue the process. So that's significantly better. It's not 100%. It's not perfectly clean and clear, but the reservoir is dirty in the truck, so aside from replacing the reservoir, I think this is about as clean as we'll get it. It's a significant improvement, and we'll move on to the next wheel. And just drain that in.

Take some brake parts cleaner. Just clean that up. So just repeat these steps going in order. So starting at the passenger side rear, to driver's side rear, to passenger side front, to driver's side front. When you're done, put the rubber cap on if you still have it. Make sure you clean up any brake fluid that you may have spilled, and that your reservoir is topped off to the max level that's on the side, and, of course, replace your cap.

As a comparison, this is brand new, clear fluid right out of the bottle. This is what we ended up getting out of our vehicle, so it's not 100%, but it's a huge improvement over what was in there, and pretty much the reservoir for the master cylinder is dirty. It would have to be replaced to get it fully cleaned, but this is a huge improvement, and definitely improved braking in this vehicle. This is why you should never neglect your brake fluid as a service.

Thanks for watching. Visit us at 1AAuto.com for quality auto parts, fast and free shipping, and the best customer service in the industry.