afonseca

So I just replaced the pads/rotors on my '08 Cayenne and everything seemed to go smooth until I tried to flush out the brake fluid. I'm now stuck with no brake pedal (goes to the floor when pressed).

Here's what happened:
I tried using the Motive Power Bleeder since I'd used it with success in the past on other cars and read that others had used it on the Cayenne just fine. I filled the Motive with fresh fluid and pressurized the system. I went to the right/rear to start the bleeding and only had a little bit of fluid slowly ooze out then stop. I tried the other bleeder on the same wheel and the same result. The fluid that did come out looked okay, not particularly dirty or anything.

So I depressurized the system to see what was going on in the reservoir. It was full of fluid but the Motive level didn't go down much at all so it looked like it wasn't working. I then went to try a pedal bleed with some help and again, only got a little bit of fluid out and then just started getting air. I looked in the reservoir again and this time the fresh fluid was now mixed with some pretty dirty fluid. I suctioned it out as the fluid that was originally in there wasn't that dirty looking to begin with. I refilled it with clean fluid and tried to pedal bleed again with no luck. The caliper is dry and only air comes out now and I get no pressure at the pedal (falls to the floor).

I tried turning on the ignition thinking maybe the ABS system is preventing the fluid from flowing to the rear but that didn't make a difference and I get a low brake fluid warning.



The brake fluid is at Max in the reservoir but it just doesn't drain/flow when I push the brake pedal down with the bleeder open. I have the car on jack stands so I'm going to try putting the wheels back on so I can start it and see if that gets things flowing again.

I'm out of ideas to try so if anyone has some thoughts on what's going on or suggestions I should try next I'd really appreciate it!

knfeparty

Not to be a smartass, but you didn't accidentally put the Motive on the power steering reservoir instead of the brake fluid reservoir did you? I just bled my 955 with the motive. I use the dry technique and am careful not to get it too dry, but the wet technique should definitely work. Even at 8 psi I get good flow out of the bleeders. I did not have to use durametric to activate ABS or anything like that.

wrinkledpants

Oof. That was my first guess. I'm not sure how one could easily suction out all the old brake fluid with that screen in the way, and it won't be "dirty." Maybe a bit murky from mixing with moist air, but by no means dirty.

afonseca

Okay, so that was an idiot move on my part.

I suctioned out all the fluid in the PS reservoir now and wiped the inside down as best I could. I'm thinking I should probably flush whatever might have gotten in the system out to hopefully prevent any damage. I'm starting to search online, anyone have some flush instructions?

knfeparty

Well fortunately the correct fluid, ch202, is cheap and available at most regular auto parts stores. I would buy several pints of it, find a low point in the system to disconnect a hose, and drain out all the fluid you can. Reconnect everything, refill, start the car and cycle the steering, then repeat. It's gonna take a few flushes to clean out all that brake fluid. How much did you put in?

afonseca

Thanks, I don't know how much made it in but guessing not much as my "problem" was that it wasn't draining at all. Although I did suction out some fluid that looked dirty as mentioned so some mixing took place.

I've got some CHF202 now so will have to figure out what hose to disconnect as I haven't found any references online yet.

John Welch.

I know firsthand that you are not the first person to think the power steering reservoir was for the brakes. ;-)

afonseca

Thanks, yeah, I feel pretty stupid making that mistake but at least I know I won't make THAT one again.

MJG911

Don't feel bad. Several years back when I restored a 240Z I couldn't bleed the brakes, so I took it to a shop and I had the calipers swapped left to right with the bleed screws on the bottom. Fortunately, it took a while for the shop to even figure out why it wouldn't bleed!

afonseca

Thanks, it's my first time doing brakes on this car. The CHF202 is a blue/green'ish color and looks different than what was in there but I'm not making excuses.

afonseca

So quick update, I've completed the actual brake fluid flush with the Motive and it went smooth. As expected there was some air in the lines but all clear now and I get a firm pedal.

So now I have the undertray off and I'm looking for a power steering hose to disconnect down there to flush that system. I'm having a hard time finding any pictures online that might explain how to get at one. Anyone have experience doing that?

hahnmgh63

You may have had CHF11S in there, more greenish. Although your year should have had the CHF202. They are both interchangeable but Porsche swapped from the 11S to the 202 in 2005, so pretty much the 2006 model year on came with the 202.