i have got a 90 thunderbird and i have to add brake fluid at least once a week. i checked all the lines and the wheel cylinders and can't find any leaks. anyone know what to check now? thanks

 

Check the master cylinder and see if the fluid is leaking out the back and into the booster. If you're adding once a week, that's a big leak and should be relatively easy to spot.

 

I had a 94 Thunderchicken and had the same delema. I hunted for months, finally found out it was leaking from the front left caliper. just a slight drip only when the brakes where pushed firmly. What I had to do was pull it somewhere that you can lay paper down under the tires/ lines ect. and pump the brakes and look for drips/leaks.

Good luck

 

Sometime when the master cylinder leaks the leaking fluid is sucked into the engine through the vacume hose and you never see any dripping . That's where I would start looking ( the inside of the hose will be wet ) , then if all is ok there pull the tires off and look at the calipers ....But my money ( what there is of it ! ) is on the master cylinder .

 

ok i will pull the hose and check it thanks