2008 Ford F 250 This Truck 6 4l Diesel Hydro Boost Brakes Power Steering Works

2008 FORD F-250
50,298 MILES
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RLEWIS1945
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  • 1 POST
This truck is a 6.4L diesel with hydro-boost brakes. The power steering works fine. If I hit the brakes it stops fine. However, if the brake pedal is pushed down hard the pedal will gradually sink to the floor. With the key off the pedal never sinks to the floor. If I hold the pedal down hard and start the motor the pedal drops right to the floor. What's wrong?
Oct 16, 2012 at 7:10 PM
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HMAC300
  • ✓ASE Certified Mechanic
  • 48,601 POSTS
  • ASE Certified Mechanic
soundslike the master cylinder is bad or air in system.
Oct 16, 2012 at 7:53 PM
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