Missing Brake fluid?

[liquidlunch1812]

I have a 1988 2.0 Sierra and it seems to be eating brake fluid. I dont see any leaks comming from anywhere. I seem to have to refill the fluid to get it back to the correct level about monthly. I have blead the brakes and all, any information would be helpful.
Thanks

[KimMG]

How much are you losing? As the brake pads wear, it takes more fluid in the system to keep the pistons extended in the calipers.

[liquidlunch1812]

i'm missing about 1 pint every month and a half or so.

[KimMG]

Have someone step on the brake pedal while you check all the lines for leaks. Check the rear brakes to make sure the wheel cylinders for leaks.

[rhandwor]

If you haven't found it checking the lines and calipers,and wheel cylinders look at the back of the master cylinder at the vacuum booster to see if it is wet.
This is a area a lot of leaks happen.

[scoinzy]

i have had cars in the past that leak fluid down the bulk head ending up under the carpet in the drivers footwell it may be worth checking.Good luck.

[snupytcb]

also check vacume line connected to brake booster. if your master cyl. is leaking it may be getting back into the motor.

[festiva1]

i have a ford festiva that leaks when setting and when u start engine white billows out the exaust

[rhandwor]

After you park for the evening disconnect the vacuum line to the vacuum canister. Plug the hose with a bolt. Start the car in the morning if it still is smoking check for a leaking head gasket. Leaking valve seals will also cause smoke. Put your car on jack stands and use a flashlight hunting for brake fluid. Check from the master cylinder and follow the brake tubing to each wheel.
Normally a leaking master cylinder will drip down the back as the vacuum booster if not leaking won't pickup brake fluid.