Trail Maintenance: Bleeding Brake Fluid on a 5th Gen 4Runner

Bleeding Brake Fluid on a 5th Gen 4Runner – Step by Step Guide + Brake Fluid + Tools & Materials

The brake system is one of the most important systems on any 4Runner or any vehicle for that matter. When talking about brake maintenance what usually comes first to mind is probably changing pads and rotors. The brake fluid however probably comes in fourth after “should I upgrade to a big brake kit? I’m already changing the pads and rotors” Why doesn’t the brake fluid get the attention it needs? Probably because it doesn’t squeal every time when the brake pedal is pushed to let you know it needs some TLC.

So why does brake fluid need to be changed?

Well, two main reasons; firstly brake fluid absorbs moisture from the atmosphere which in turn evaporates during braking and creates air pockets within the brake line. Since air compresses this will lead to a reduction in braking performance. Additionally, the moisture build-up within the lines can also corrode the metallic components within the system.

Secondly, the brake system is not a sealed system, therefore outside contaminants such as dirt can enter the system. This combined with wear and tear of the pads and rotors the brake fluid will degrade over time. So yea, show that DOT-3 some TLC.

Find it online:

• DOT 3 Brake Fluid (x2 32 oz.): Check Price

Toyota Maintenance Info

• Recommended Service Interval: 2 years or 60,000 miles which ever comes first
• Brake Fluid Type: DOT-3
• Note: The procedure below is written for a solo job, but having an extra person definitely helps.

Installation Overview

Tools & Materials:

• 10mm wrench
• 3/16 ID Clear Tubing (2-3 feet)
• Syringe or Turkey Baster
• Plastic Bottle (x2 ~48 oz.)
• Brake Cleaner
• Shop Towels
• Disposable Gloves
• Weights (I used a filled ammo can)
• GoPro + Tablet (optional)

Step 1. Remove cover to brake fluid reservoir

Pull the rubber gasket above the brake fluid reservoir outwards and slide the gasket off of the hook holding it in place. Depress the two tabs and lift the cover up and out of the way.

Once you have full access to the reservoir clean it thoroughly.

Step 2. Make the brake fluid catch bottle

Cut about 2 feet of clear tubing. Take the bottle cap of the catch bottle and drill a hole for the tubing, the tube should fit snug thru the cap. Drill a second hole through the cap this will function as a vent hole so a small hole will do.

Now assemble the cap, hose, and bottle together. Position the hose so that the open end touches the bottom of the bottle. I have mine coiled around the base of the bottom.

Once the bottle is complete open up the brake fluid reservoir. Using a syringe suck out the old brake fluid and deposit it into the catch bottle. Do this until most of the old fluid has been sucked out (I stopped when the fluid level reached “MIN”).

Check and make sure that the tube is submerged under the old brake fluid.

Step 3. Top off Brake Master Cylinder Reservoir

Slowly pour the new brake fluid into the reservoir until it reaches slightly past “MAX”. Put the lid back on the reservoir. Brake fluid is very corrosive so take extra care when pouring.

Step 4. Bleeding Front Brakes

*Flushing brakes does not require removing the wheels, I’ve removed mine in order to take better pictures.

1. Start with the front passenger side brake. Locate the bleeder valve on the brake caliper and remove the rubber protective cover.

2. Attach the hose from the brake fluid catch bottle. Make sure the bottle and tubing are positioned so that the tubing makes an upward arc between the bleeder valve and the bottle. This will ensure any air from the brake lines travels up and away from the bleeder valve.

3. Get in the driver’s seat and slowly pump the brake pedal a few times.

4. Using a 10mm wrench unscrew the bleeder valve about a quarter turn. At this point, brake fluid should be flowing out of the valve slightly. If not that’s ok once the brake pedal is depressed fluid should come out.

5. Get back into the driver’s seat and slowly pump the brake pedal 5 times. Get out and verify that nothing is leaking and that there is still plenty of brake fluid in the reservoir.

If everything looks good continue pumping the brake pedal in increments of 5-10 times and checking the brake fluid reservoir and catch bottle.

Once the brake fluid in the tube is the same color as the new brake fluid and no air bubble is present stop and close (Torque: 8 FT-LBS) the bleeder valve and reinstall the rubber protective cover.

6. Remove the tube from the bleeder valve and snip off about an inch, this will ensure a tight fit on the next bleeder valve. Reinstall the rubber protective cover.

7. Top off the brake fluid reservoir and repeat the process again on the front driver side.

8. Once both front brakes are complete pump the brake pedal to check for pedal pressure and leaks around the bleeder valves.

Tip: If you have a GoPro that can connect to a phone or tablet it’ll help speed things along by having the GoPro stream what’s going on at the bleeder valve while you pump the brake pedal. You’ll still have to keep an eye on the brake fluid reservoir, but that’s one less thing to check.

Step 5. Bleeding Rear Brakes

1. Start with the rear passenger side brake. Locate the bleeder valve on the brake caliper and remove the rubber protective cover.

2. Attach the hose from the brake fluid catch bottle. This is not as critical for the rear but as a precaution make sure the tube makes a slight upwards arc.

3. Get into the driver seat and turn the ignition to the “ON” position. But do not start the vehicle.

4. Take the weight and position it so that the weight will apply constant pressure to the brake pedal.

5. Using a 10mm wrench open the bleeder valve. At this point, the pump motor should be pumping the brake fluids through the line. You’ll be able to hear the pump cycling, let this run for about 60 seconds. Close the valve and remove the weight from the brake pedal. If the brake fluid in the tube is the same color as the new brake fluid and no air bubble is present then the bleeding is complete, stop and close (Torque: 8 FT-LBS) the bleeder valve and reinstall the rubber protective cover. If not repeat the process again for another 60 seconds.

Note: To reduce the risk of damaging the pump do not exceed 100 seconds of continuous pumping.

6. Top off the brake fluid reservoir and repeat the process again on the rear driver side.

7. Pump the brake pedal to check for pedal pressure and leaks around the bleeder valves.

Step 6. Adjust Brake Master Cylinder Reservoir

Inspect all calipers for leaks and adjust the brake fluid reservoir so the fluid level is between “MIN” and “MAX”.

Final Thoughts

This is pretty easy maintenance and very satisfying to see the difference between the old vs. new fluid. The old brake fluid is on the left and you can visibly see the discoloration, while the new fluid is clean and clear. I also had some small air bubbles come out during this. Definitely worth doing if your 4Runner hasn’t had its brakes bleed in 2 years or 60,000 miles.