1997 Ford F350 Brake Problem

1997 FORD F-350
208,000 MILES • V8 • 2WD • AUTOMATIC
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DUKEBMX
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  • 1 POST
Brakes pedal became very hard?

Brakes are there but feels like no power assist suddenly. Sometimes brakes will feel ok but then problem comes right back?

Also lost AC about the same time?

Could there be any relation?

Thanks, Jon
Oct 12, 2008 at 11:33 AM
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RASMATAZ
  • ✓ASE Certified Mechanic
  • 75,992 POSTS
  • ASE Certified Mechanic
HARD BRAKE PEDAL

Lack of power assist may be due to low engine vacuum, a leaky vacuum hose or a defective booster. Sometimes a faulty check valve will allow vacuum to bleed out of the booster causing a hard pedal when the brakes are applied. This condition can be diagnosed by starting the engine (to build vacuum), shutting it off, waiting four or five minutes, then trying the brakes to see if there is power assist. No assist means a new check valve is needed.

A quick way to check the vacuum booster is to pump the brake pedal several times with the engine off to bleed off any vacuum that may still be in the unit. Then hold your foot on the pedal and start the engine. If the booster is working, the amount of effort required to hold the pedal should drop and the pedal itself may depress slightly. If nothing happens and the vacuum connections to the booster unit are okay, a new booster is needed (the vacuum hose should be replaced, too).
Oct 12, 2008 at 11:38 AM
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