Mobil 1 EP vs Castrol EDGE w/Titanium

[kohnen]

Originally Posted By: The Critic
Friend is coming over... It will probably turn into a brake flush... 2006 Prius

Thanks.


Please, unless you fully understand what you're doing, DON'T try to do a brake fluid flush. There are two very good reasons for this:

1) Because it's a hybrid, the Prius braking system is NOTHING like a typical braking system. The brake pedal is used to control the computer (for regenerative braking) before it actually puts on the brakes. There is a stroke simulator and lots of various computer controlled valves on that system. You need the dealer computer to control the valves to actually get it to release fluid.

2) The brake fluid almost never sees elevated temperatures (because of the regenerative braking). The car tries to capture as much energy and put it back into the battery as possible. As a result, the brakes are actually used very little. This causes brake fluid to last quite long.

I have an '07 Prius (same generation) with 120 kmiles and the brake fluid looks absolutely pristine.

Go look on priuschat if you want more info on the brake flushes. Most DIY flushes on that board eventually involve tow trucks.

Good Luck!

 

[The Critic]

Originally Posted By: kohnen
Originally Posted By: The Critic
Friend is coming over... It will probably turn into a brake flush... 2006 Prius

Thanks.


Please, unless you fully understand what you're doing, DON'T try to do a brake fluid flush. There are two very good reasons for this:

1) Because it's a hybrid, the Prius braking system is NOTHING like a typical braking system. The brake pedal is used to control the computer (for regenerative braking) before it actually puts on the brakes. There is a stroke simulator and lots of various computer controlled valves on that system. You need the dealer computer to control the valves to actually get it to release fluid.

2) The brake fluid almost never sees elevated temperatures (because of the regenerative braking). The car tries to capture as much energy and put it back into the battery as possible. As a result, the brakes are actually used very little. This causes brake fluid to last quite long.

I have an '07 Prius (same generation) with 120 kmiles and the brake fluid looks absolutely pristine.

Go look on priuschat if you want more info on the brake flushes. Most DIY flushes on that board eventually involve tow trucks.

Good Luck!


Thanks for the warning, but I have Techstream Lite and have already flushed the brake fluid twice on my 2011 Prius. Appearance has little correlation to the condition of the brake fluid, since brake fluid is hygroscopic and should be replaced periodically in order to maintain an adequate boiling point and to prevent corrosion. Granted, the Prius brake system sees far less use than a conventional brake system, but this does not exempt it from the moisture issue.

 

[fdcg27]

This really makes no sense, no more than saying that you can't bleed an ABS brake system without special tools.
The master cylinder of the car must push fluid out to each corner, which then applies braking force.
The calipers must have bleed valves.
Therefore, you could simply gravity flow fresh fluid through the system starting with the right rear and going from there.
The regen braking setup wouldn't be of any relevance.
As long as you make sure not to run the resovoir dry, no worries.

 

[The Critic]

Originally Posted By: fdcg27
This really makes no sense, no more than saying that you can't bleed an ABS brake system without special tools.
The master cylinder of the car must push fluid out to each corner, which then applies braking force.
The calipers must have bleed valves.
Therefore, you could simply gravity flow fresh fluid through the system starting with the right rear and going from there.
The regen braking setup wouldn't be of any relevance.
As long as you make sure not to run the resovoir dry, no worries.


The system is brake-by-wire, so pushing the pedal has no effect. When I flushed the brake fluid on my 2011, Techstream would send the proper signals to the control system when it was time for a particular wheel.

The rear wheels are bled by the accumulator pump (think that's the correct name): when prompted, you push and hold the pedal, loosen the screw at the appropriate wheel, then the brake fluid is pumped out very quickly.

To do the fronts, when prompted by Techstream during the air bleed procedure, they are bled in a somewhat conventional manner.

I have never tried to do this job without Techstream. The service manual does outline a way of doing it without Techstream on the Gen III Prius, but it is very sketchy because in the event of a hiccup that triggers a code, the car may be undrivable.