4700 2 Wheel Hydraulic Brake Drag

Discussion in 'International Forum' started by aawil, Oct 29, 2021.

  1. aawil

    aawil Bobtail Member

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    Feb 2, 2021
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    My 4700 rear brakes were dragging, you could hear them squeaking when first starting the truck and driving. I replaced the calipers, pads, and had the rotors turned. The old calipers were junk the boots were falling apart and the pistons weren't in very good shape. Since then I drove the truck about 80 miles round trip and when I got back I could put my hand on the front rotors and they were cold, the rear rotors were hot and I could put my hand on them but if I left it there for long I would burn myself. I removed the rubber brake hoses from the frame to the rear calipers and can blow through them each way with my mouth. Could the Master Cylinder be keeping the rear brakes applied? Where should I look next?
    Thanks
     
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  3. feldsforever

    feldsforever Road Train Member

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  4. aawil

    aawil Bobtail Member

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    Feb 2, 2021
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    I jacked up the front and rear of the truck and spun all the wheels and the fronts spin with almost no friction and they continue spinning when I stop turning them. The rears turn but stop very quick after I stop spinning them. I also loosened the master cylinder bolts about halfway in case it was being slightly depressed and that didn't change anything either. Is it possible the new pads need worn in and will loosen up in time?
     
  5. Dino soar

    Dino soar Road Train Member

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    I never worked on disc brakes on trucks but on cars most of them have pins that have to be greased for the calipers to slide on.

    If they are not greased the caliper won't release properly and the brakes will drag.
     
  6. aawil

    aawil Bobtail Member

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    Feb 2, 2021
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    This is my first time with these, they have a strange mounting setup with a wedge and a spring. I thought I greased them up good, My uncle says he's worked on them before on an old ford, I'm going to have to take these back apart and see if I can see something binding and have him take a look.
     
  7. Inderjit

    Inderjit Medium Load Member

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    I don't think there is a problem. If your brakes were dragging you would
    not dare touch the rotors. Do the front brakes apply? The front rotors should not be cold.
     
  8. Goodysnap

    Goodysnap Road Train Member

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    I would keep driving it and shoot the rotors with a temp gun after some time at work. Rears will do more of the stopping power and also come on first. If the steer axle is light and not doing a lot of the braking it will be cooler.

    Did the slides go in fairly easy, but snug? Crappy design and old technology really........
     
  9. aawil

    aawil Bobtail Member

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    Feb 2, 2021
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    Okay, I had to tap the slides in with a hammer, they went in pretty easy once they were at the right angle and lined up correctly. I can move the front calipers up and down a little bit when the brakes are released but not the rears. The front brakes do apply.
     
    Last edited: Oct 31, 2021
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