Do turbos have a valve protecting the Master Cylinder?

[douglas vincent]

So my brakes are going. In the sense of the pedal needs to be pumped once before they firm up. This just started yesterday.

There is no dripping fluid, the fluid level is just right, and all the pads and rotors are less than 10k old. There is no way I can think of air getting in the system.

Could I have damaged my master cylinder by running boost into it versus vacumn? Was I stupid and didnt install a 99 cent part? Or is it something completely unrelated?

[jake15]

i think turbos do have a special host the connects to the brake booster that has some type of one way valve or something in it..... i dont know if that is your problem but i could be related in some way.

[vrg3]

Quick clarification: the vacuum hose goes to the brake booster. The booster actuates the master cylinder.

Almost all cars have a check valve in the brake booster vacuum hose; our Legacies have it built into the hose, turbo and non-turbo alike.

Your problem is most likely that the master cylinder is on its way out. Even if you service your fluid regularly (which most people don't), master cylinders do eventually fail.

Thankfully they're not too hard to replace. Drain the fluid, disconnect the level sensor connector, undo the four 10mm pressure lines with a flare nut wrench, undo the two 12mm-hex nuts holding the master cylinder to the brake booster, and then pull the master cylinder out.

Installation is basically the reverse of removal. Be sure that the inverted flare fittings are clean, both the pipe and the threads. And you should prime the master cylinder by bench bleeding it, bleeding it on the car before connecting its pipes, vacuum bleeding the brakes, or just bleeding with the engine running and pushing really hard.

[Legacy777]

I've tried bench bleeding and bleeding it on the car before connecting the lines.....it's a complete mess, and really doesn't work well. Just bleed it well with the engine running.