986 Forum - The Community for Porsche Boxster & Cayman Owners - View Single Post - Brake pedal stops normally then slowly fades to floor. Master cylinder? Booster?

michaelpetersen3 · 10-18-2020, 04:45 PM

Just wanted to close out on my issue above. Thanks to eBay and $75 I replaced the ABS unit with an identical part number, i.e. had the same stamped part number and was from the same model year vehicle ('01 986 S).

After replacing the ABS unit and a brake fluid flush to all four corners, the brakes feel like new. No sponginess and they do not slowly compress after the initial contact.

When it failed, I was running stock pads but with race class slick tires (Toyo Proxes RR), and intentionally pushing the brakes to threshold several times on every lap (including occasional ABS activation). I suspect I was pushing the ABS to its limits. It would have had max pressure and coefficient of frictions of the tires was beyond what the engineers tested for 20 years ago.

Hope this helps the next guy...

(BTW, as most of you know, the brakes on the 986 and 996 are virtually identical other than tuning)

10-18-2020, 04:45 PM	#46
michaelpetersen3 Registered User Join Date: May 2019 Location: Deephaven, MN Posts: 21	ABS replacement worked. Just wanted to close out on my issue above. Thanks to eBay and $75 I replaced the ABS unit with an identical part number, i.e. had the same stamped part number and was from the same model year vehicle ('01 986 S). After replacing the ABS unit and a brake fluid flush to all four corners, the brakes feel like new. No sponginess and they do not slowly compress after the initial contact. When it failed, I was running stock pads but with race class slick tires (Toyo Proxes RR), and intentionally pushing the brakes to threshold several times on every lap (including occasional ABS activation). I suspect I was pushing the ABS to its limits. It would have had max pressure and coefficient of frictions of the tires was beyond what the engineers tested for 20 years ago. Hope this helps the next guy... (BTW, as most of you know, the brakes on the 986 and 996 are virtually identical other than tuning)