2002 Mercedes Benz 500sl Brakes

2002 MERCEDES BENZ 500SL
264,000 MILES • 5.0L • V8 • RWD • AUTOMATIC
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JOSEPH ANNOH
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The brake pedal goes flat on the floor every morning when the weather temperature is between 12c and 13c. But it works perfect when the weather warms up. What's the problem?
Jul 28, 2015 at 5:57 PM
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MHPAUTOS
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There is nothing that would cause this that is temp related, if the pedal sinks to the floor you may have a by passing master cylinder, this can happen with light brake pressure with heavy pressure the seals in the master cyl will seal against the bore with more efficiency, if you had air in the system, the pedal would not recover, I would be checking the master first.
Jul 29, 2015 at 3:27 AM
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JOSEPH ANNOH
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But I just changed the master cylinder
Jul 29, 2015 at 12:48 PM
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MHPAUTOS
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Did you bleed it on the bench before fitting,
Jul 30, 2015 at 3:36 AM
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JOSEPH ANNOH
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I don't know if my mechanic did. Was he supposed to do that before fitting the master cylinder?
Jul 30, 2015 at 8:36 AM
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MHPAUTOS
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You should always bench bleed a master cyl before fitting, I would be looking at air still trapped in the system.
Jul 30, 2015 at 2:45 PM
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JOSEPH ANNOH
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Is it possible to take out the master cylinder, bleed it on the bench and fit it back. If so, how much will be your labor to get it done right?
Jul 30, 2015 at 7:21 PM
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MHPAUTOS
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Don't take it off now it is fitted, just bleed it in the car at the pipe unions at the master cyl.
Aug 1, 2015 at 1:14 AM
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JOSEPH ANNOH
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Thank you so much
Aug 2, 2015 at 6:45 AM
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MHPAUTOS
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OK, hope all works well.
Aug 2, 2015 at 2:34 PM
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JOSEPH ANNOH
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Where are you guys located?
Aug 9, 2015 at 5:35 PM
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MHPAUTOS
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I am in Australia, all other techs are based in the US
Aug 11, 2015 at 2:40 AM