Carpokes Porsche Forum

hey all, I went to flush all the brake fluid from my car yesterday and now the pedal is softer and travels way further than it did before. Early on in the process I didn’t keep an eye on the reservoir and some air got into the system. When that happened I started leaking fluid between the master cylinder and the brake booster. After bleeding what seems like all the air out, the leak stopped. Did I break my master cylinder or is there just still air in the lines?

There's only one way it can leak. In my experience the master needs replaced. If it leaked once, it will again. Unless maybe there is some voodoo going on with Porsche masters that I'm not aware of. I'm sure you know, but make sure to clean up the fluid or paint will start coming off.
When I flushed my lines, making sure no air got in, I also had a softer pedal afterwards. I then went through the process again with my power bleeder and it seemed to help. Although it still doesn't feel as still as I think it should. Some of that I am attributing to the old rubber lines. My plan is to replace them with braided at some point. I will likely do that master then too since I have no idea how old it is.

Dang, not the answer I was hoping to hear You’re probably right though, I’ll try bleeding the system again and evaluating after that. I also noticed on my front left caliper I kept getting pinhole sized bubbles that just wouldn’t go away. Not sure if it was from in the system or air coming through between the bleeder nipple and hose.

I read the following last night in the new issue of Panorama. May not apply but it is plausible.

PSU_Crash wrote: Sun Oct 19, 2025 1:55 pm There's only one way it can leak. In my experience the master needs replaced. If it leaked once, it will again. Unless maybe there is some voodoo going on with Porsche masters that I'm not aware of. I'm sure you know, but make sure to clean up the fluid or paint will start coming off.

The 944 master cylinder is a Muggle -- no voodoo magic at all. If it has or had an external leaked, I'd replace it too.

Poorsche44 wrote: Sun Oct 19, 2025 1:39 pm hey all, I went to flush all the brake fluid from my car yesterday and now the pedal is softer and travels way further than it did before. Early on in the process I didn’t keep an eye on the reservoir and some air got into the system. When that happened I started leaking fluid between the master cylinder and the brake booster. After bleeding what seems like all the air out, the leak stopped. Did I break my master cylinder or is there just still air in the lines?

You probably damaged the master cylinder by running it dry. The leak you saw is a classic sign. Re-bleed the brakes thoroughly. If the pedal is still soft, the master cylinder needs to be replaced.

Tom wrote: Sun Oct 19, 2025 3:47 pm The 944 master cylinder is a Muggle -- no voodoo magic at all. If it has or had an external leaked, I'd replace it too.

"The power of voodoo. Who do? You do." Seems applicable with some of these German engineered wonders