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Brake issue in non-Prius. Idea?

Discussion in 'Fred's House of Pancakes' started by Skoorbmax, Jan 29, 2011.

  1. Skoorbmax

    Skoorbmax Senior Member

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    I have another car with disc brakes. This summer rears were changed (rotors and pads).

    A few thousand miles later I got a bad rubbing sound on the right rear only when it's hot and when the brakes are not applied. Even a tiny application of brake force removes the sound.

    I replaced only the rear rotor. 6 weeks later (today) sound is coming back again.

    Clearly two bad rotors is not likely. That side is noticeably hotter than the left side. This leads me to think a bad caliper. I do know that when I had the car jacked up and I'd apply brakes then feel the wheel for spin it seems to spin ok.

    Is it possible the rear bearing or wheel is off in some manner? When the rubbing sound is on and I go around a corner the sound stops while cornering, but I've had this in the past in brakes before, since even a mild lean does force a good wheel to "tilt" a bit, thus changing the forces on the rotor.

    At this point I guess caliper, though but hate wasting time :)
     
    #1 Skoorbmax, Jan 29, 2011
  2. dogfriend

    dogfriend Human - Animal Hybrid

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    Sticking caliper or sticking slider pins so the caliper doesn't "float"

    Edit: In fact, since you are in Western NY where everything rusts like crazy, I would bet that the slider pins and/or the slider pin holes in the caliper are corroded.
     
    #2 dogfriend, Jan 29, 2011
  3. SPEEDEAMON

    SPEEDEAMON Professional Car Nut

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    When was the last time brake fluid was flushed and changed? Should also check sticking parking brake
     
    #3 SPEEDEAMON, Jan 30, 2011
  4. Skoorbmax

    Skoorbmax Senior Member

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    Never done the fluid. Have meant to for years. In this vehicle the parking brake is a separate drum system so it's not related to the disc problem. I think other than a caliper pin or caliper itself, now that I remember--when I changed the brakes with non-oem pads they were VERY stiff in the calipers, even though I greased the points they make contact. I think the pads themselves are not sliding easily within the caliper and I may very slightly grind down their "ears" that hold them in the caliper so that they can slide better in and out.
     
    #4 Skoorbmax, Jan 30, 2011
  5. Darwood

    Darwood Senior Member

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    What kind of car?
    Who did the rotors? Did they lube the pins or not?
    The slider pins are the most likely culprit, but there are other possibilities. I had a Ford Taurus that kept doing this and I eventually found that the brake lines had rusted, causing constriction in the brake lines, which eventually led to a leak in the line. Also, the wheel bearing could be going, leading to increased heat and warping on that rotor. You should not need to replace brake fluid, only to bleed the lines to make sure there is no air in the line. It's easy enough to do and it pushes out the tainted fluid at the end of the line in the process.
     
    #5 Darwood, Jan 30, 2011
  6. Skoorbmax

    Skoorbmax Senior Member

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    mazda MPV, I did the pins. :) Will try and find time this week to take apart again...

    Have never bled the lines but have meant to for a long time on the car (years) hehe
     
    #6 Skoorbmax, Jan 30, 2011
  7. SPEEDEAMON

    SPEEDEAMON Professional Car Nut

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    Without more info, such as how old is the car, mileage, accidents? its difficult to diagnose. For instance if you bought it used, you don't know if the previous owner could have hit the curb with the wheel, in which case bearings will be out of whack. Or worse yet if it had an accident, the rear alignment will be off. Usually wear on the tires will indicate this.
    Good luck on finding the source.
     
    #7 SPEEDEAMON, Feb 2, 2011
  8. Skoorbmax

    Skoorbmax Senior Member

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    No accidents or issues. I've owned it most of its life...
     
    #8 Skoorbmax, Feb 2, 2011
  9. Darwood

    Darwood Senior Member

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    Inspect the brake lines for rust or damage and bleed the brakes to make sure there is no air in the lines. Also, feel the temperature of the lug nuts after driving and see if one side is significantly hotter than the other, It's easy to do and will eliminate some of the possible causes.

    The next step is to replace the bearings.
     
    #9 Darwood, Feb 2, 2011
  10. cit1991

    cit1991 New Member

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    Master cylinder sticking? I had an Audi do that once. MC stuck enough that the internal return spring didn't push the piston back far enough to re-uncover the vent hole. As the calipers got hot, the fluid couldn't pressure back out to the reservoir, so the pressure went up..more friction...etc.

    To test, get it hot enough to have the brake drag problem..not rolling freely. Loosten the brake line fittings at the MC one by one. If it frees up with a little squirt of fluid, then the MC is holding fluid pressure out and is sticking.
     
    #10 cit1991, Feb 3, 2011
  11. Skoorbmax

    Skoorbmax Senior Member

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    Last night I finally got around to this. I believe the problem is that the aftermarket pads were not sliding properly in the caliper brackets. I had a different pair of pads (diff brand) doing the same thing when I put them in last night. Both were just so stiff in the brackets that they had to be tapped/hammered out to even get them to move in and out. This was causing excessive rubbing, as the caliper would compress them around rotor but they'd not release sufficiently. I recall in the past on other brake jobs that the pads should be lose enough in there that they can move quite freely if not even "fall over" if you tilt the bracket horizontal after putting them in place. I used my grinder (seriously useful tool for $20-30) to very slightly shorten their length so that they could move better in the brackets and drove to work, so far without the sound.

    Thanks for the posts!
     
    #11 Skoorbmax, Feb 16, 2011
  12. Rebound

    Rebound Senior Member

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    This is really good information. Thanks!
     
    #12 Rebound, Feb 17, 2011
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