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90 F250 rear brakes lock up

Discussion in 'Ford Trucks' started by F250BLUES, Sep 26, 2005.

  1. F250BLUES

    F250BLUES Junior Member
    Messages: 2

    Rear brakes slowly apply and lock up while driving...have replaced shoes, wheel cyls. hardware, antilock light is on. Only thing I haven't replaced is brake hose in rear...any suggestions?
  2. Frozen001

    Frozen001 Senior Member
    from Rome NY
    Messages: 908

    Have you checked the proportioning valve??? just a thought...
  3. F250BLUES

    F250BLUES Junior Member
    Messages: 2

    I will try that...Is there an actual valve in there? never had one apart, Thanks.
  4. 84deisel

    84deisel Senior Member
    Messages: 697

    if the shoes are adjusted too tight the hotter they get the more they will apply. The proportioning valve is located on the frame under the master cylinder.
  5. ironworks01

    ironworks01 Member
    Messages: 48


    Big shoe towards the front? Or adjusted to tight. Or leaky axle seal. That's my 3 cents.
  6. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    I have an 89,it should be the same system as mine.
    Any brake pedal pump when applied? Did you have the drums machined and checked? Fronts are working and not needing bled or pins rusted bad? The emergency brake cables tend to stick, holding the brakes on more then needed. Smelling brakes all the time?

    One key is the antilock light is lit. Look at the wiring at the sensor on top of the axle,also it switches off when in 4X4, so look at those wires too. I did a wiggle test while the ignition was on and my son watched the light. It was in the pig tail off the axle sensor,broken wire.