Brakes problem
1994 Toyota 4Runner 6 cyl Two Wheel Drive Automatic 195000 miles
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brakes fail , replace master cylinder,blead brakes, and master cylinder. Still have no brakes. requires excessive force unbrake pedal to stop vehicle. No leaks.

Excessive force = test vacuum booster and check valve. Shut off the truck, pump pedal until all air is bled out(if any) hold pedal dwn, start truck, pedal should sink a bit, if not booster or valve on the vacuum line is bad. Check the valve by sucking through both ends, air should pass in one direction only!