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

Rotmilky · 07-04-2017, 06:22 PM

As it turns out, I had a new set of steel braided brake lines ready to install. I meant to install them during the master cylinder replacement a few days ago. After I installed the new master cylinder, I got excited, bled the system and then realized I forgot to install the brake lines. I was too lazy to crack open the hydraulic system again, so I put them on a shelf in the garage. After several suggestions to replace the brake lines above, I decided to get unlazy and install them. Did that this afternoon and bled the system. Still the same problem...seems to be completely unfazed by the new master cylinder or the new brake lines.

Certainly, I've now got 8 new fittings that maybe I didn't get tightened correctly that might cause a small leak. I can't see fluid leak and I tightened the fittings until I started to get nervous that I was going to stretch the threads. I used flare wrenches on both fittings, so I could get them pretty darned tight.

New booster will be in tomorrow. I'll install that. In the interim, is there any way the clutch hydraulics can affect the brakes? For example, is it possible that a bad slave cylinder would feed back into the brakes?

07-04-2017, 06:22 PM	#16
Rotmilky Registered User Join Date: Feb 2017 Location: New Mexico Posts: 42	As it turns out, I had a new set of steel braided brake lines ready to install. I meant to install them during the master cylinder replacement a few days ago. After I installed the new master cylinder, I got excited, bled the system and then realized I forgot to install the brake lines. I was too lazy to crack open the hydraulic system again, so I put them on a shelf in the garage. After several suggestions to replace the brake lines above, I decided to get unlazy and install them. Did that this afternoon and bled the system. Still the same problem...seems to be completely unfazed by the new master cylinder or the new brake lines. Certainly, I've now got 8 new fittings that maybe I didn't get tightened correctly that might cause a small leak. I can't see fluid leak and I tightened the fittings until I started to get nervous that I was going to stretch the threads. I used flare wrenches on both fittings, so I could get them pretty darned tight. New booster will be in tomorrow. I'll install that. In the interim, is there any way the clutch hydraulics can affect the brakes? For example, is it possible that a bad slave cylinder would feed back into the brakes? __________________ V.H. Whitley Owner of Waaay too many vehicles Non Porsche :1959 International B120, 1960 International B120, 2015 BMW M3 Porsche: 1997 986, 2001 986S, 1968 911L, 1968 911S, 2005 911, 1984 928, 2008 Cayenne S.