Brake Fluid Mystery

[DeUddah]

Problem is with a 2008 Toyota Blade (I guess similar to an Auris I guess). Brake fluid in the master cylinder reservior has been disappearing.

There are no visible signs of leaks on the floor, rims lines etc.

The strange thing is that because of this problem the car has not been driven for two weeks but I have been keeping an eye on the fluid in the master cylinder and even though the engine has not been started the fluid still disappears in a day or so. So I top the fluid up again and about a day and half later it has fallen in the reservoir again without any driving.

I have noted that fall in the fluid stop just below the min mark and just in line with the level where the vacuum line leaves the brake booster.

There is no sign of leakage into the vaccum line from the brake booster, no mushy paint.

All mechanisms I checked are stumped on this one. Dealer suggest a new master cylinder but that will take few weeks on order.

Any thoughts

[Brian R.]

In case you haven't done this, I would check the tightness and dryness of all the connections in the brake lines that you have access to. Replacing the master cylinder is the last resort.

[DeUddah]

Thanks Brian R. The now-three week search and checks continue with no sign of any obvious problems or leaks.

[harleyguy]

I don't really think it's the problem but I have seen on 90's gm fluid leaking into the booster. Is this a manual trans and if so does it run off the same resivor?