DIY: Rear Brake Fluid Change / Bleed Using a Scan Tool
Update: I wrote this before I finished the front brakes. It turns out it doesn't work on the front! I had to do it manually, pumping the brake pedal.
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I changed the brake fluid in my 4runner today, and it was relatively straightforward, but it would be helpful to DIY to make it go quicker. I wanted to do it with a scan tool, but if you want to try it without, see this thread: http://www.toyota-4runner.org/4th-gen-t4rs/145716-brake-bleeding-w-abs-w-o-sst-tool.html The scan tool makes it somewhat easy to do the job alone.
First, why change the brake fluid? Brake fluid is hygroscopic, so it absorbs moisture over time. The system is "sealed", but moisture can still find its way into the reservoir or past the caliper seals as the pistons move. Wet fluid has a lower boiling point, so there is more chance of brake fade during long, hard braking (not that you should be doing that in normal driving anyway). Heat also seems to damage brake fluid, and it may have corrosion inhibiting additives that get used up over time. It's important to have clean, dry fluid to protect the hydraboost unit, and to keep the calipers well lubricated. I suspect that the number of stuck calipers and failed hydraboost units could be reduced by changing the fluid on a regular basis.
For some reason Toyota doesn't recommend any specific interval for brake fluid changes. Honda recommends every 3 years. BMW recommends it every two years.
Parts and supplies needed:
Tools needed:
I set up my scan tool per this thread: http://www.toyota-4runner.org/gener...ta-tis-techstream-8-x-windows-7-8-64-bit.html I got the USB dongle on Amazon, and used software from one of those links (I don't have a CD drive, so I couldn't use the CD that came with it). I have it running on my Mac laptop with Windows XP in a VMWare Fusion virtual machine. VMWare can pass USB devices through, so there's no problem there. One of the instruction sets said to set the region to Europe, but don't do that. I had to set it to North America for it to recognize my 4runner.
1. Make sure the scan tool can connect to your car. Open the VSC ECU, and look for Utilities. There should be an Air Bleed function. That's what I used.
2. Park the vehicle on a level surface, set the parking brake, and chock the wheels. I like to lock the center diff so that the parking brake also locks the front wheels.
3. Loosen the lug nuts on the wheel(s) you want to work on. I did the rear wheels then the front, but you could do all of them at once.
4. Lift up the vehicle and secure it on jack stands. For the rear I put the jack under the differential (careful not to hit the drain bolt) and put jack stands on the axle. For the front I lift by the lift point under the stock skid plate and put jack stands under the frame near the front doors.
5. Remove the wheel(s)
6. Clean the bleed nut, and remove and clean the rubber cap. Open the hood and clean the brake fluid reservoir. It's important not to get contaminants in the brake fluid reservoir.
7. Check the brake fluid level. If it's near min, add some fluid now, otherwise leave it so you don't mix as much old fluid with the new fluid. I couldn't find a way to drain the reservoir since there is a pinhole under the fill cap that keeps fluid from splashing out. I ended up pushing all the old fluid out the brake lines.
8. Turn the ignition to ON. You might want to start the vehicle so you don't drain the battery, but it will work with the engine stopped, too. Set up the scan tool and find the screen to bleed the first wheel. The standard order is to start with the farthest (Rear Right) and move to the closest one last (Front Left). I started with the Rear Left since it was easier to see the laptop and press the brake pedal.
9. Install the fuel line over the bleeder nipple. If you can't find 3/16 ID fuel line, the diameter of the narrowest part of the bleeder is 0.216", and apparently 1/8" ID stretchy silicone tubing or 5/32 ID tubing will work. It should be clear so you can see the color of the fluid. Secure the end of the tubing in your catch container.
10. Put the flare nut wrench on the bleeder, and open it about 1/4 turn.
11. Activate the air bleed function for the wheel you are working on. Fluid will flow out for about 2 seconds, then it will stop. You can close the bleeder once the fluid stops, even though the pump will still be running.
12. The nest step in the software is an annoying 20 second delay, so hit next to start the timer.
13. While you are waiting, check the fluid level in the reservoir. Don't let it get below Min. I think it will beep when the level reaches Min.
14. Repeat until lighter fluid starts to come out. New brake fluid should be very light, almost clear. Brake fluid with some moisture turns amber colored. If it's dark, black, or has stuff floating in it, that's bad. Particles floating in the brake fluid may indicate that a seal somewhere in the system is deteriorating. It's not clear how dark the fluid can be and still be acceptable. https://www.google.com/search?q=brake+fluid+new+old+color&espv=2&source=lnms&tbm=isch
15. Alternate method: For the rear calipers, holding the brake pedal down will pump fluid through. That's a lot faster since you don't have to wait 2 seconds for every 2 seconds of pumping. Just be careful not to run the reservoir empty (I think it will beep and stop pumping when it gets low, but I'm not sure), and give the pump some time to rest periodically.
15 1/2: Note: The scan tool only works to activate the rear brakes. For the front, there is a clicking noise, but no fluid is pushed out. It's weird because I think the system can actuate the front brakes on its own for DAC/TRAC.
16. Clean excess brake fluid, torque the bleeder to 11 N*m (112 kgf*cm, 8 ft.*lbf), and reinstall the rubber cap.
17. Move on to the rest of the wheels. It should only take a few cycles to get clean fluid once you got the old fluid out of the reservoir on the first one.
18. Rinse off any excess brake fluid with water. Reinstall wheels. Tighten with a torque wrench is available.
19. Inspect brake fluid level (procedure from the service manual).
(a) Turn the ignition switch off, depress the brake pedal 20 times or more (until the pedal reaction feels light and pedal stroke becomes longer), and adjust the fluid level to the MAX level.
(b) When the ignition switch is turned to the ON position, brake fluid is sent to the accumulator and the fluid level decreases by approximately 5 mm from the level when the ignition switch is off (normal).
20. Check that everything is installed properly, and go for a test drive around the block.
21. Clearly label used fluid and take it for recycling/disposal.
I pushed almost a full quart of fluid through the left rear brake (I did that one first) in an attempt to get all the old stuff out of the reservoir and pump. It was hard to tell when it turned lighter, so I might have done too much. The old fluid in the reservoir really wasn't that bad. Most of the old fluid that came out was medium yellow.
The next ones only took a couple bleed cycles before lighter fluid came out and a lot less yellow fluid came out, as expected.
Using the scan tool I was able to do the rear brakes by myself. After activating the solenoids, I had enough time to move to the bleeder and close it as soon as it stopped pumping.
Sorry I don't have any pictures. I had just enough time to finish before it got dark. Note that this procedure doesn't really get all the old fluid out of the caliper. Someone posted their way to do that on here, and it was basically open the bleed screw, and press the pistons all the way in to pump out the old fluid. That sounds like it's best done when you change the brake pads.
Update: I wrote this before I finished the front brakes. It turns out it doesn't work on the front! I had to do it manually, pumping the brake pedal.
-----
I changed the brake fluid in my 4runner today, and it was relatively straightforward, but it would be helpful to DIY to make it go quicker. I wanted to do it with a scan tool, but if you want to try it without, see this thread: http://www.toyota-4runner.org/4th-gen-t4rs/145716-brake-bleeding-w-abs-w-o-sst-tool.html The scan tool makes it somewhat easy to do the job alone.
First, why change the brake fluid? Brake fluid is hygroscopic, so it absorbs moisture over time. The system is "sealed", but moisture can still find its way into the reservoir or past the caliper seals as the pistons move. Wet fluid has a lower boiling point, so there is more chance of brake fade during long, hard braking (not that you should be doing that in normal driving anyway). Heat also seems to damage brake fluid, and it may have corrosion inhibiting additives that get used up over time. It's important to have clean, dry fluid to protect the hydraboost unit, and to keep the calipers well lubricated. I suspect that the number of stuck calipers and failed hydraboost units could be reduced by changing the fluid on a regular basis.
For some reason Toyota doesn't recommend any specific interval for brake fluid changes. Honda recommends every 3 years. BMW recommends it every two years.
Parts and supplies needed:
- 1-2 quarts DOT 3 brake fluid. I used 1 quart + 12oz, but I may have used too much. I used Prestone DOT 3. DOT 4 should be compatible, but I read somewhere that the additives may be different, and it't really best to use DOT 3 if that's what it calls for.
- 2 feet of 3/16" ID flexible transparent plastic fuel line ($2.99 at the auto parts store)
- Rags
- Nitrile gloves
- Water to rinse spilled fluid
- Clear container to catch old fluid
Tools needed:
- 10mm flare nut wrench ($6.99 for a cheap one)
- 21mm socket or the lug nut wrench in the trunk
- Safety glasses
- Optional: 10mm socket and a torque wrench set for 11N-m
- Optional: Torque wrench for the lug nuts
- Scan tool, such as a Mini VCI cable and a laptop with the Techstream software.
- A way to lift the car off the wheels, such as a jack and jack stands
I set up my scan tool per this thread: http://www.toyota-4runner.org/gener...ta-tis-techstream-8-x-windows-7-8-64-bit.html I got the USB dongle on Amazon, and used software from one of those links (I don't have a CD drive, so I couldn't use the CD that came with it). I have it running on my Mac laptop with Windows XP in a VMWare Fusion virtual machine. VMWare can pass USB devices through, so there's no problem there. One of the instruction sets said to set the region to Europe, but don't do that. I had to set it to North America for it to recognize my 4runner.
1. Make sure the scan tool can connect to your car. Open the VSC ECU, and look for Utilities. There should be an Air Bleed function. That's what I used.
2. Park the vehicle on a level surface, set the parking brake, and chock the wheels. I like to lock the center diff so that the parking brake also locks the front wheels.
3. Loosen the lug nuts on the wheel(s) you want to work on. I did the rear wheels then the front, but you could do all of them at once.
4. Lift up the vehicle and secure it on jack stands. For the rear I put the jack under the differential (careful not to hit the drain bolt) and put jack stands on the axle. For the front I lift by the lift point under the stock skid plate and put jack stands under the frame near the front doors.
5. Remove the wheel(s)
6. Clean the bleed nut, and remove and clean the rubber cap. Open the hood and clean the brake fluid reservoir. It's important not to get contaminants in the brake fluid reservoir.
7. Check the brake fluid level. If it's near min, add some fluid now, otherwise leave it so you don't mix as much old fluid with the new fluid. I couldn't find a way to drain the reservoir since there is a pinhole under the fill cap that keeps fluid from splashing out. I ended up pushing all the old fluid out the brake lines.
8. Turn the ignition to ON. You might want to start the vehicle so you don't drain the battery, but it will work with the engine stopped, too. Set up the scan tool and find the screen to bleed the first wheel. The standard order is to start with the farthest (Rear Right) and move to the closest one last (Front Left). I started with the Rear Left since it was easier to see the laptop and press the brake pedal.
9. Install the fuel line over the bleeder nipple. If you can't find 3/16 ID fuel line, the diameter of the narrowest part of the bleeder is 0.216", and apparently 1/8" ID stretchy silicone tubing or 5/32 ID tubing will work. It should be clear so you can see the color of the fluid. Secure the end of the tubing in your catch container.
10. Put the flare nut wrench on the bleeder, and open it about 1/4 turn.
11. Activate the air bleed function for the wheel you are working on. Fluid will flow out for about 2 seconds, then it will stop. You can close the bleeder once the fluid stops, even though the pump will still be running.
12. The nest step in the software is an annoying 20 second delay, so hit next to start the timer.
13. While you are waiting, check the fluid level in the reservoir. Don't let it get below Min. I think it will beep when the level reaches Min.
14. Repeat until lighter fluid starts to come out. New brake fluid should be very light, almost clear. Brake fluid with some moisture turns amber colored. If it's dark, black, or has stuff floating in it, that's bad. Particles floating in the brake fluid may indicate that a seal somewhere in the system is deteriorating. It's not clear how dark the fluid can be and still be acceptable. https://www.google.com/search?q=brake+fluid+new+old+color&espv=2&source=lnms&tbm=isch
15. Alternate method: For the rear calipers, holding the brake pedal down will pump fluid through. That's a lot faster since you don't have to wait 2 seconds for every 2 seconds of pumping. Just be careful not to run the reservoir empty (I think it will beep and stop pumping when it gets low, but I'm not sure), and give the pump some time to rest periodically.
15 1/2: Note: The scan tool only works to activate the rear brakes. For the front, there is a clicking noise, but no fluid is pushed out. It's weird because I think the system can actuate the front brakes on its own for DAC/TRAC.
16. Clean excess brake fluid, torque the bleeder to 11 N*m (112 kgf*cm, 8 ft.*lbf), and reinstall the rubber cap.
17. Move on to the rest of the wheels. It should only take a few cycles to get clean fluid once you got the old fluid out of the reservoir on the first one.
18. Rinse off any excess brake fluid with water. Reinstall wheels. Tighten with a torque wrench is available.
19. Inspect brake fluid level (procedure from the service manual).
(a) Turn the ignition switch off, depress the brake pedal 20 times or more (until the pedal reaction feels light and pedal stroke becomes longer), and adjust the fluid level to the MAX level.
(b) When the ignition switch is turned to the ON position, brake fluid is sent to the accumulator and the fluid level decreases by approximately 5 mm from the level when the ignition switch is off (normal).
20. Check that everything is installed properly, and go for a test drive around the block.
21. Clearly label used fluid and take it for recycling/disposal.
I pushed almost a full quart of fluid through the left rear brake (I did that one first) in an attempt to get all the old stuff out of the reservoir and pump. It was hard to tell when it turned lighter, so I might have done too much. The old fluid in the reservoir really wasn't that bad. Most of the old fluid that came out was medium yellow.
The next ones only took a couple bleed cycles before lighter fluid came out and a lot less yellow fluid came out, as expected.
Using the scan tool I was able to do the rear brakes by myself. After activating the solenoids, I had enough time to move to the bleeder and close it as soon as it stopped pumping.
Sorry I don't have any pictures. I had just enough time to finish before it got dark. Note that this procedure doesn't really get all the old fluid out of the caliper. Someone posted their way to do that on here, and it was basically open the bleed screw, and press the pistons all the way in to pump out the old fluid. That sounds like it's best done when you change the brake pads.
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