monsterness

- 98.5 avant quattro wagon

Doing the brakes today, replaced all of the pads and rotors, and hooked up a motiv power-bleeder to the reservoir. Pumped it up to ~10PSI to check the seals, it was fine for a few minutes, then there was a hissing/bubbling sound. A close inspection shows slight cracking in my reservoir. Does this need to hold pressure?

CC Rider

There are rubber seals in the cap with some room to expand under pressure. It's not so much a pressurized system as a way to keep air out of the brake lines.

When using your pressure bleeder, I think you are supposed to loosen the cap to prevent a buildup of pressure. At the same time, you have to keep an eye on the fluid level in the resevoir and replace it as necessary during the bleeding procedure.

I'm not sure but it sounds like you may hvae pushed it beyond it's expected pressure level.

pointby

Same thing happened to mine with a pressure bleeder. Its OK to run with it cracked if it doesn't leak until you can replace it.

Shep 1.8T

fluid.

It sucks, BTDT, siphon (NOT with YOUR MOUTH) all the fluid out as best as you can, then lay a bunch of rags around the resivour and yank up. You should catch the majority of the fluid on the rags, and daub up the rest. Put the new resivour in, and fill with fluid. I wouldn't exceed 5 psi, but that's just me.

monsterness

replacing the reservoir. I used 10 PSI because that's what the instructions said. 10 PSI is also a very small amount of pressure - its clear that the reservoir was not in good shape to begin with if 10 PSI was enough to cause it to leak. The brakes work just fine for now, and I'll replace it and all the fluid next weekend. Thanks for your thoughts.
-Rich