DWS964

Completed my first brake fluid change/flush last night, including the ABS accumulator (thanks to Adrian's recommendations in his book) and the clutch slave cylinder. I was surprised at the volume of fluid flushed out of the hydraulic accumulator (for both the ABS and the PDAS on my C4). The fluid didn't look too bad coming out of the calipers, but I was also surprised to see quite a few bubbles coming out of two of the calipers. I have owned the car for about 6 months, and the PO's records showed that the last time the brake fluid was changed was several years ago (but only 9,000 miles ago). Then, I flushed the clutch slave cyl. My clutch pedal had been feeling notchy, stiff, and hanging on the return. I found the clutch bleeder valve without too much problem, thanks to all of the posts here on Rennlist, but it was still a pain. Anyway, here is a pic of what oozed out. I only drove the car a short sanity-check trip last night, but the clutch seems to feel better. Well, it has to be better after getting that sludge out of there. We will see how it performs this week. Given the ugly nature of what was in there, I will probably flush it again soon. By the way, I used a Motive pressure bleeder for the first time - amazingly simple bleeding job; I don't know why I haven't used one before. Plus, as Adrian points out - you have to use a pressure bleeder on the 964's with the hydraulic assist.

DWS964

Per Adrian, the PDAS differential lock slaves should also be bled when changing the fluid. Of course, I did not have access to a Hammer to activate the solenoids to be able to accomplish this. After seeing the state of the clutch slave fluid, I suspect that the PDAS slaves are in equal condition.
The last brake fluid change was done by an independent, but well-known shop; but I wonder how many dealers and shops perform the full, proper fluid change on C4's (brakes, booster, clutch, PDAS)?

Does anyone have an alternative method for activating the PDAS to enable flushing of the differential lock slaves?

Darrell