1997 Ford F150 sticking front brakes

1997 FORD F-150
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JJDOGWOODKNOB
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  • 3 POSTS
Brakes problem
1997 Ford F150 6 cyl Four Wheel Drive Manual 150k miles

I have a 97 f150 4x4. I had a problem with the front brakes, when you drove the truck it started out fine, the longer I drove, the harder the pedal would get, It would eventially lock the front brakes to the point I could not drive it.
I then replaced the front brake lines and hoses, rebuilt the calipers and put on new pads.
I thought with what I did, it would fix the problem, however during the test drive after these repairs, the problem is still there. The longer you drive, the harder the pedal gets and I know the front brakes are dragging badly. Any ideas what to try next??
Thank You in advance
Nov 1, 2009 at 12:30 PM
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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).
Nov 1, 2009 at 1:24 PM
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