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  1. #1
    Join Date
    Dec 2009
    Location
    Hawkhurst, Kent, UK
    Posts
    49

    Default ABS Hydraulic Pump?

    XC70 2001. Recently a "pump like" noise was heard at low speeds which became greater when turning left but disappeared when the lightest brake pressure was applied.

    After a great deal of chin scratching the problem area was identified (by a friend sitting on the engine as we went around in tight lh circles!), the noise was the pump on top of the abs modulator cutting in. Why it whould do it when we turn left is a mystery. My understanding of the abs system is that the hydraulic modulator regulates pressure in the braking system.

    So, whilst I think I have identified where the noise comes from - the car brakes normally and the abs system works (we tried on gravel, the abs pulsing is felt and the wheels lock at <5mph), I am now completly at a loss as what to do next...and am open to advice........

    Many thanks in advance for your help.

    John

  2. #2
    Join Date
    Apr 2003
    Location
    Devon PA
    Posts
    11,409

    Default

    I may still have a good used pump if that's what you wind up needing,
    I think it will work on an 01 (not sure)
    Let me know.

    EDIT
    Whilst means you're across the pond. These are very heavy so shipping may rule it out.
    Nevertheless let me know as it would cost WAY less then new (which is big $$$$$)

  3. #3
    Join Date
    Dec 2009
    Location
    Hawkhurst, Kent, UK
    Posts
    49

    Default

    Many thanks JRL, I' have a feeling that that is just what I am goild to need!!

  4. #4
    Join Date
    Feb 2010
    Location
    Virginia Beach
    Posts
    4,116

    Default

    Quote Originally Posted by JohnBuckles View Post
    XC70 2001. Recently a "pump like" noise was heard at low speeds which became greater when turning left but disappeared when the lightest brake pressure was applied.

    After a great deal of chin scratching the problem area was identified (by a friend sitting on the engine as we went around in tight lh circles!), the noise was the pump on top of the abs modulator cutting in. Why it whould do it when we turn left is a mystery. My understanding of the abs system is that the hydraulic modulator regulates pressure in the braking system.

    So, whilst I think I have identified where the noise comes from - the car brakes normally and the abs system works (we tried on gravel, the abs pulsing is felt and the wheels lock at <5mph), I am now completly at a loss as what to do next...and am open to advice........

    Many thanks in advance for your help.

    John
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  5. #5
    Join Date
    Dec 2009
    Location
    Ashford Kent UK
    Posts
    48

    Default

    Sounds like the cable to the sensor is at fault , or it's pulling the sensor away as the steering is turned .

  6. #6
    Join Date
    Dec 2009
    Location
    Hawkhurst, Kent, UK
    Posts
    49

    Default

    Thanks,

    I'll check and let you know

    John

  7. #7
    Join Date
    Dec 2009
    Location
    Hawkhurst, Kent, UK
    Posts
    49

    Smile Resolution

    After a serious amount of chin scratching the ABS problem has been solved.

    The Pulse Wheel (the toothed wheel that generates current pulses to the computer to indicate wheel speed) had cracked - it fell off the hub when I removed the brake disk. I'm so pleased it was not the ABS modulator!!!!


    Interestingly I also had the spring fail on that side as well as having various suspension anomalies there.........I suspect a smash at some time although its clean on the check....

    Thought I would let you know........

    John

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