Brake Fluid System
From Boxster Tech
[edit] Flushing the Brake System
Since brake fluid is hygroscopic, Porsche recommends flushing the brake fluid system with new fluid every two years. Flushing involves pushing the old fluid out at each brake caliper with new fluid that is injected in from the brake fluid resevoir in the front trunk (usually under slight pressure).
Instructions can be found on Trygve's Boxster Project: Brakes: Bleeding and Flushing page. Typically, one switches between Ate (pronounced "ah-tay") Gold Typ 200 and Ate Super Blue Racing brake fluids (Manufacturer: Continental Teves). The two fluids have identical performance and by switching colors, one can tell when the old fluid has been replaced with new.
Brake fluid will cause paint to bubble and peel, and therefore must not touch any painted areas.
The job is made easier with a Motive Power Bleeder (Typically $49), which attaches to the brake fluid resevoir and pushes the new fluid through the brake system and out at each of the eight brake bleeder screws at the calipers (two at each wheel) using a few pounds of pressure.
[edit] Flushing the Clutch
As the clutch uses the same brake fluid system for its operation, it is also recommended that the clutch is bled at the same time as the brake system is flushed. Some have reported a better feel of the clutch after bleeding it. The clutch bleed screw is a difficult to get to, located on the left rear side of the transmission. It can be accessed from the rear of the car once it is safely up on jacks:
The bleeder valve has a ribbed rubber cap that comes all the way off.
Flushing the clutch requires two people, because the clutch pedal must be pressed all the way down to the floor before fluid will flow through the clutch bleed valve. It may work better by pumping the clutch pedal up and down. Again, safety is paramount because one person will have to be under the rear of the car opening and closing the bleeder screw.
Once completed, the clutch pedal may not spring back up on its own. If not, it will need to be exercised several times while shifting through gears by carefully driving in a safe area in order to get the pedal to respond properly.
Note that the clutch bleeder uses a 9MM wrench while the brake bleeder valves use an 11 MM wrench.
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