front brakes locking up

has anyone had or known of any problems with mercedes ml front brakes locking up the front wheels. I have a 2000 model ml and the front brakes keep locking up. Have fitted new discs and pads but as soon as
you depress the pedal the wheels lock up and will not free off when the pedal is released.
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A malfunction with the BAS system, perhaps?
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It is probably a sign of binding caliper... you need to replace the caliper.
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Yes, sounds like either bad calipers or else something was not assembled correctly when you installed the new pads. If calipers are on the way out, then failing after new rotors and pads is common, because that's when the corroded piston gets pushed all the wa back in.
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wrote:

It would seem strange that both front wheel swould lock up because of a binding caliper. For both to fail simultaneously this soon seems really strange to me. If I am reading this correctly, and BOTH front wheels are locking up and not releasing, I'd suspect something else. In older cars I'd go with a bad proportioning valve, but I'm not sure the M class has them. However, if it is only one wheel, then I'd go with the caliper diagnosis. just my two cents.
Bill
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It could be the soft brake lines. They have a date code on them. What does it say ? 5 yrs or older means replace them right now.
When they get old they can swell, and accept hydraulic pressure but they won't release it and the calipers stay "on".
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That was the first thing that came to mid. That happened on a '75 2002 I had. But I figured materials technology would have progressed far enough by now that lines should last longer than 7 years. Especially on a Mercedes. That seems really short. Oh well.
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Nah, rubber swells. And it's still the thing to use. Just change 'em on schedule and you should be ok.
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Richard Sexton wrote:

IF the system is still a vacuum actuated one, check the vacuum check valve on the booster, especially if there are separate valves for front and rear.
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question what would be the cause and effect if the caliper was left as is for some time ie how long can it be used in this state (curious
"trader4" wrote
> > It is probably a sign of binding caliper... you need to > replace the caliper. > > > Yes, sounds like either bad calipers or else something was not > assembled correctly when you installed the new pads. If > calipers are > on the way out, then failing after new rotors and pads is > common, > because that's when the corroded piston gets pushed all the wa > back > in.
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Causes have already been suggested. As to how long it can be used in this state:
"as soon as you depress the pedal the wheels lock up and will not free off when the pedal is released. "
the answer to that should be obvious. It shouldn't be used at all, unless maybe you were fleeing a volcano about to explode.

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It will heat up your rotor unitl hot orange. Warp your rotor... cook your brake pads... may start a fire on rubber parts if hot enough... and as usual... smokes coming out of your wheelwell.
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