Where is my master cyl. fluid going?
 

A couple days ago I filled my master cyl.. Since then I only drove ~4 mi. Checked this morn and it's all gone! There's no wet spots on the drive where it's been sitting since. No wet signs anywhere in the area under the hood. I'm thinking I have a bad master cyl. but I don't see anything wet in the brake booster through the vacuum connection or in the vacuum line to the booster itself. Your help is gratefully appreciated! Larry PS: This in for a '88 Eldorado w/4.5

check your carpet just by the brake pedal ...



.

Yup, even get your head up under the dash with a flash light and you'll probably see brake fluid trailing down from the firewall.

If you've lost that much fluid in that short amout of time, not likely it's leaking outside anywhere else you would see it. Either on the ground or backside of a tire or something. So it's probably leaking inside the car the only place it can, where the master cylinder bolts to the firewal.