According to the 1996 Mercury Cougar Owner Guide :
( DOT 3 brake fluid , meeting Ford specification ESA-M6C25-A )
A 1993 Mercury Cougar takes ( DOT 3 brake fliud )
On a 2000 Mercury Cougar : The brake fluid reservoir is also the clutch fluid reservoir
The brake and clutch fluid systems are supplied by the brake fluid reservoir ( according to the 2001 Mercury Cougar Owner Guide )
The master cylinder is shot. The seals inside are allowing the fluid to by-pass.
DOT ( 3 ) brake fluid in North America , DOT ( 4 ) in Europe
you can only fill your brake fluid from the reserve.
According to the Owner Guide , the brake and clutch fluid systems are supplied by the same reservoir on a 1999 Mercury Cougar
On a 2000 Mercury Cougar : The brake fluid reservoir is also used as the clutch fluid reservoir
DOT 3 will work just fine
it probably has a leak...
For a 1996 Ford Bronco : DOT 3 brake fluid ( meeting Ford specification ESA-M6C25-A )
Is the brake fluid level low in your brake master cylinder in the engine compartment ?