Brake rotor rust opinions

Discussion in 'General Motoring' started by BF, Jan 6, 2005.

  1. BF

    BF Guest

    04' Pacifica that's used mainly for trips and sits for long periods in
    between. (and it's been very rainy for the last week or two)
    This afternoon, I headed out in the car and at the end of the block applied
    the brakes for the stop sign. Felt like all four rotors had warped half an
    inch. Got back up to speed and applied the brakes a bit more aggressively a
    couple of times. Still had bad vibrations.
    Drove about 15 minutes at highway speed to my first stop. At speed, it felt
    like tire(s) out of balance. Still had braking vibration. Checked the rotors
    and they were badly rusted, as expected. By my next stop, another 15 minutes
    at speed both the tire imbalance feeling and braking vibrations had gone.

    recommendations / opinions about how best to resolve this rust on rotors

    Just drive normally?
    Drive fast with quick stops until clear?
    Drive slow with slow / low pressure stops until clear?
    Reverse of either of the above two?
    Doesn't matter, no harm is done either way?
    Doesn't matter the same harm is done no matter what?
    Other opinions?
    Crackpot opinions?

    BF, Jan 6, 2005
  2. I doubt they were "badly" rusted. Surface rust appears on rotors almost
    instantly in humid locations, and it can build up to coat the entire
    surface of the rotor (except where the pad physically prevents water
    access) quickly. This is why it felt like the rotors had warped; there was
    a non-rusty patch on each of the four rotors. The proliferation of
    open-frame alloy wheel designs that let you (and every raindrop) see the
    pretty brakes has greatly aggravated the condition in recent times, though
    it can occur with any kind of wheel.

    It doesn't mean there's anything wrong with the car or the brakes. It does
    mean you need to get in the habit of dragging your brakes the first few
    hundred feet when the car's been sitting long enough for the condition to
    occur. Don't drive especially slowly or quickly, just drag the brakes
    until they clean up, then use them normally after that.

    Daniel J. Stern, Jan 6, 2005
  3. BF

    maxpower Guest

    I have no idea what Chrysler did to the Pacifica front and rear rotors, they
    are really junk metal, they will pit really bad if sat for awhile. I had a
    set already machined at work on my bench and threw them away because the
    humidity in the shop ruined them, normally driving the vehicle will clean em
    up but in some cases we have been replacing them. There are no TSBs for this
    Glenn beasley
    Chrysler Tech
    Do not replace the rotors for an appearance concern...Unless a customer is
    experiencing brake noise or brake related roughness / vibration issues DO
    NOT REPLACE a rotor(s) based on appearance only. The lining material
    selected for this vehicle may pick up iron which becomes embedded in the
    friction material resulting in scoring of the rotor surface. Rotor scoring
    does not necessarily contribute to roughness, vibration, noise or any other
    type of degraded brake performance.
    maxpower, Jan 6, 2005
  4. BF

    BF Guest

    Didn't mean to imply that I was worried about the rotors. But was wondering
    if people had concerns about pads or other components and how they would
    best to try protect them.
    The rotors are just great chunks of cast mild steel, so it would take
    decades for corrosion to do any real damage to them. But I don't know if
    there are other considerations to worry about.
    BF, Jan 7, 2005
  5. Nope.
    Daniel J. Stern, Jan 7, 2005
  6. BF

    Sam Steele Guest

    Some of the shops I deal with use a zinc rich weld through primer that body
    shops use to spray into the vented slots of the rotors and thus provide a
    sacrificial anode that will prevent surface rust.
    Sam Steele, Jan 7, 2005
  7. BF

    Joe Guest

    You may not need this info, but you mentioned tire balance. You should
    expect your tires to thump also if you don't drive for a long time. It might
    take several miles to take the flat spot out of them, but eventually they
    should get round again.
    Joe, Jan 7, 2005
  8. BF

    BF Guest

    Thanks Joe,
    Could be part of it but I suspect most was the rust intermittently hitting
    the calipers.
    BF, Jan 7, 2005
  9. That's a pretty cool idea..
    Going to have to remember that one when the wheels come off in the
    spring, to put on the summer tires.
    Sportster4Eva, Jan 14, 2005
  10. BF

    KaWallski Guest

    There are 2 (two) things to consider in the makeup of the brake rotors and
    drum's material. Beyond basic metalurgy and wear, the chemical makeup of the
    material and the location of use create the circumstance. However the metal
    fails to remain inert for more than the two reasons as I implied earlier.
    Chemical and Biological reasons. Look it up. The Titanic is rotting away
    faster than so-called experts (or had previously) explained. Ask any
    MicroBiologist. Rust can happen due to many reasons but there is a third
    that is often overlooked. Iron eating bacteria. It exists in more situations
    than discussed.

    Many times I wondered why a so-called dry block rotted away after only a few
    months while only a few feet away another block looked pristeen.

    So don't discount the obvious but don't dismiss the remote until you know
    all the reasons...
    KaWallski, Jan 18, 2005
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