SOFT BRAKE PEDAL

  • Tiny
  • yacadee
  • 2000 Ford F-150
  • V8
  • 4WD
  • automatic
  • 90,000 miles

My ford f-150, 4 double piston disc brakes and abs (yr-2000, 4wd) when stopped with pressure on brake pedal starts to creap forward when in drive. Changed primary and secondary lines at master cyclinder. Changed master cyclinder three times and also front calipers and pads. It still creaps forward. Next i'll be changing rear calipers. I feel i'm still sucking air from somewhere or there is still air in the system which I can't get out. I've gravity bleed, vacuum bleed and the 2 person, pump it up 6 times, keep pressure on brakes and open up line routine. With enging off and also on. Whats going on ----please let me know----. Vin#1FTRX18WXYNA26038.

Friday, November 26th, 2010 AT 12:51 AM

7 Answers

  • Tiny
  • Dr Loot
  • Expert
  • 2,332 posts

Explain to me how you bleed the master cylinder?

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Friday, November 26th, 2010 AT 5:08 AM
  • Tiny
  • yacadee
  • Member

Bench bleed: using plastic lines and nylon fittings with master cylinder from primary and secondary exits to resevoir with this setup. Using a full stroke on plunger to a short stroke both fast and slow, waiting seconds between strokes. Also bleed when lines were attached by cracking open the line at the master with help on the brake after finding tk. Still would creap. One remanufactured and two new masters were used and all made by fenco.

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Monday, November 29th, 2010 AT 1:33 AM
  • Tiny
  • Dr Loot
  • Expert
  • 2,332 posts

I am glad to hear that you've bleed the master cylinder property, now I have another question how much pedal travel do you have before you can feel the master cylinder activating?

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Monday, November 29th, 2010 AT 1:43 AM
  • Tiny
  • yacadee
  • Member

3" to4"

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Thursday, December 2nd, 2010 AT 3:07 PM
  • Tiny
  • Dr Loot
  • Expert
  • 2,332 posts

Thats to much, do you still have the old masters cylinder? You will have to measure the depth of your old master cylinder, remove the current one make sure they are the same, if not adjust Rod on brake pedal to master cylinder.

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Thursday, December 2nd, 2010 AT 5:24 PM
  • Tiny
  • yacadee
  • Member

The old one did the same as the others. Thats one other reason why I changed the master 3 times. Could it be the rabs valve needs to be bled and if so where can I find it.

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Friday, December 3rd, 2010 AT 4:02 AM
  • Tiny
  • Dr Loot
  • Expert
  • 2,332 posts

You stated 3" to4" before the break pedal made contact, you do not need to remove any of the brake lines on bolt the master cylinder, move it forward you can bend the lines a little bit just make sure you do not kink them, you see the rod that goes into the master cylinder with a nut on the end it is adjustable bring out about a 1" reinstall Master and see how much play you have, you should only have about a half an inch at the pedal before contact.

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Friday, December 3rd, 2010 AT 4:42 AM

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