993 brake and clutch problems

[xerxes5]

Hi all,

A couple weeks back I posted a question about the ABS pump on my 993. As I've discovered, old fluid had caused more than one person to replace their ABS pump, and brake/clutch cylinders.

Before replacing mine, I flushed the system with some cheap Dot 3 fluid. Sure enough, the fluid looked like molasses with whip cream.. and the reservoir had the telltale gunk in the bottom. bad bad bad. The rubber nipple covers still had black lacquer on them... I had been running 10 year old brake fluid!

Immediately after flushing the system, the clutch pedal no longer hung, but the brakes still got soft. Now for the amazing part. After a week of driving, the problem was gone! The brake pedal suddenly firmed up again and didn't sag.

This weekend, I went ahead and tor the system apart (I'd already gotten the parts) and the gunk that HAD been in the reservoir was gone! The Dot 3 dissolved out whatever had been causing the problem!

Since I already have the parts, I'm going ahead and replacing stuff, but it looks like this might be a simple fix to an expensive problem. My theory is that the gunk that settles out is the silicone added to Dot 4 fluids to raise the boiling point. The Dot 3, which doesn't have this, might be dissolving it back into solution. If someone else with this problem wants to try it, I'd love to hear back if it works.

Good luck,

-Mark Flaming
San Rafael, CA

[kang]

Interesting idea. Why don't you post this in the 993 area?