Brake system flush (1 Viewer)

[zhloea]

Hi, I plan to replace that whole cylinder/booster assembly, so the bleeding process after the replacement should same as what we wrote here right? And how we can tell all the air is bleed out?

And also, if I have a mistake in one of the steps (for example, somehow get air in the system like drain out the brake fluid...,), what I should do? do it all over again or something else?

 

[ZackR]

Hi, I plan to replace that whole cylinder/booster assembly, so the bleeding process after the replacement should same as what we wrote here right? And how we can tell all the air is bleed out?

And also, if I have a mistake in one of the steps (for example, somehow get air in the system like drain out the brake fluid...,), what I should do? do it all over again or something else?

Be sure to keep the reservoir full.... If it runs empty and you get air in the system you have to start over.

 

[OEMGUY0720]

Be sure to keep the reservoir full.... If it runs empty and you get air in the system you have to start over.

Yes this is true, try not to zero out the reservoir, prepare 5-6 liters (at least that’s what I did) of on hand new brake fluid. To drain, bleed and top up the reservoir. When there is no more bubbles coming out of the drain plug when your are bleeding, that means it has no more air on the lines. Good luck

 

[zhloea]

@spressomon - ^ If you can trust them to actually bleed all 4 corners, not strip the bleeders and replace the bleeder caps....



Dont use DOT 5 ( its silicone type) 5.1 is backwards compatible - if you must.

DOT 3 in basic terms will last longer than 4 or 5.1- its less hydroscopic.

I use Toyota DOT 3 if its easy to find otherwise Valvoline synthetic Dot3/4, Prestone Dot 3 is fine too (imo). The change interval is more important than brand selection- 24-36mo +\-. Buy a brake fluid tester and check moisture content regularly (at oil change intervals- )

can we mix up the Toyota Dot3 and Prestone Dot3? or say I bought some Toyotas but not enough for flush, can I add on some Prestone?

 

[ZackR]

can we mix up the Toyota Dot3 and Prestone Dot3? or say I bought some Toyotas but not enough for flush, can I add on some Prestone?

Yes.

 

[abuck99]

can we mix up the Toyota Dot3 and Prestone Dot3? or say I bought some Toyotas but not enough for flush, can I add on some Prestone?

Technically any DOT 3, 4 or 5.1 could be mixed in. But each brand of DOT 3 (4 or 5.1) may have subtle additive differences that make ones fluid properties different from the other, which may impact seal/internal system component service life. Ive read Toyota has its own formula spec- fwiw.

 

[zhloea]

Technically any DOT 3, 4 or 5.1 could be mixed in. But each brand of DOT 3 (4 or 5.1) may have subtle additive differences that make ones fluid properties different from the other, which may impact seal/internal system component service life. Ive read Toyota has its own formula spec- fwiw.

As a crazy people who bought brand new MC, I think I am crazy enough to go to dealer only for two bottles "OEM" brake fluid~

 

[MUDnHUNDY]

Agreed. When you look at the costs of the brake system components (Brake Booster Pump, ABS Unit, Master Cylinder) and the importance of good brakes in a 6000-lb vehicle, OEM is an easy choice.

 

[African100]

As an update to those unfamiliar with brake bleeding process on the hundy's the FSM can be a little confusing so going to try to break it down a little.

1. Use a handheld vacuum pump and remove as much of the fluid from the reservoir as you can. If you have a thin tube you can work it forward and get the fluid down to about half an inch left. Ideally you would get it all out first but unless your removing the whole assembly not really possible with this setup. Then fill back up to the max line and put the cap on. Be sure as you bleed each section your are keeping on eye on the level and adding as necessary.

2. If the fluid has gotten low enough that air is in the lines or you have replaced/rebuilt/etc the booster pump and accumulator the first thing you do is bleed that part of the system. This is accomplished by the first turning the vehicle off and pumping the brake pedal 40-50 times. You will feel it get very soft and can push it to the floor with little resistance. Then turn the vehicle on and time how long the booster pump runs. You're looking for a 30-40 second time frame. If it takes longer than that then do the cycle again.

3. If you have the hand held tester or abs actuator tool then use them to follow the flush procedure. But since most of us don't have one - get an assistant (buddy or one of your kids - my ten year old thinks she is pretty cool helping out). Turn key to on without the engine running, put assistant in the drivers seat, and have them press the brake pedal three times holding it down on the third time.

3. Starting with front left wheel, get brake bleeding line with clear tubing on the bleeder valve and into a container. You can do this without removing the wheel as long as your bleeder valves are reasonably torqued from prior work. With pedal held down crack open the bleeder valve. Fluid should run for 2-3 seconds then should stop. Close the bleeder valve and have assistant pump the pedal three more times holding down on the last and do it again. Repeat until no more air bubbles or fluid runs clear/clean. Follow same procedure for front right, then the rears. The ABS and brake lights may come on during this cycle - as long as you keep the fluid in the reservoir about the min line it will clear

4. Next is to force the abs valves to work. Again if you have the toyota tools they do it for you. But if you don't then you go find some dirt, get a little speed and romp on the brakes. Do this a couple times, then go bleed all four corners again then same way. This second time you shouldn't have to open the bleeder valves more than 2-3 times per wheel.

That's it - you have flushed the brake lines. If you have done this correctly and still have a soft/mushy pedal than time to either rebuild the master cylinder or get ready for the large hit on the wallet and order the new assembly.

Happy wheeling - Scott

As an update to those unfamiliar with brake bleeding process on the hundy's the FSM can be a little confusing so going to try to break it down a little.

1. Use a handheld vacuum pump and remove as much of the fluid from the reservoir as you can. If you have a thin tube you can work it forward and get the fluid down to about half an inch left. Ideally you would get it all out first but unless your removing the whole assembly not really possible with this setup. Then fill back up to the max line and put the cap on. Be sure as you bleed each section your are keeping on eye on the level and adding as necessary.

2. If the fluid has gotten low enough that air is in the lines or you have replaced/rebuilt/etc the booster pump and accumulator the first thing you do is bleed that part of the system. This is accomplished by the first turning the vehicle off and pumping the brake pedal 40-50 times. You will feel it get very soft and can push it to the floor with little resistance. Then turn the vehicle on and time how long the booster pump runs. You're looking for a 30-40 second time frame. If it takes longer than that then do the cycle again.

3. If you have the hand held tester or abs actuator tool then use them to follow the flush procedure. But since most of us don't have one - get an assistant (buddy or one of your kids - my ten year old thinks she is pretty cool helping out). Turn key to on without the engine running, put assistant in the drivers seat, and have them press the brake pedal three times holding it down on the third time.

3. Starting with front left wheel, get brake bleeding line with clear tubing on the bleeder valve and into a container. You can do this without removing the wheel as long as your bleeder valves are reasonably torqued from prior work. With pedal held down crack open the bleeder valve. Fluid should run for 2-3 seconds then should stop. Close the bleeder valve and have assistant pump the pedal three more times holding down on the last and do it again. Repeat until no more air bubbles or fluid runs clear/clean. Follow same procedure for front right, then the rears. The ABS and brake lights may come on during this cycle - as long as you keep the fluid in the reservoir about the min line it will clear

4. Next is to force the abs valves to work. Again if you have the toyota tools they do it for you. But if you don't then you go find some dirt, get a little speed and romp on the brakes. Do this a couple times, then go bleed all four corners again then same way. This second time you shouldn't have to open the bleeder valves more than 2-3 times per wheel.

That's it - you have flushed the brake lines. If you have done this correctly and still have a soft/mushy pedal than time to either rebuild the master cylinder or get ready for the large hit on the wallet and order the new assembly.

Happy wheeling - Scott

2. If the fluid has gotten low enough that air is in the lines or you have replaced/rebuilt/etc the booster pump and accumulator the first thing you do is bleed that part of the system. This is accomplished by the first turning the vehicle off and pumping the brake pedal 40-50 times. You will feel it get very soft and can push it to the floor with little resistance. Then turn the vehicle on and time how long the booster pump runs. You're looking for a 30-40 second time frame. If it takes longer than that then do the cycle again.

Hi Scott,
I've tried doing this but every time the pump takes way longer than the 30-40sec to stop and the ABS light and alarm come on every time. It's takes a couple of minutes for the pump to stop and the ABS light and alarm to go off. Do I need to this repeatedly in order to achieve the 30-40 sec time frame?